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CHAPTER 16 Blood

STUDENT LEARNING OBJECTIVES

At the completion of this chapter, you should be able to do the following:

1.Summarize the basic functions of blood.

2.Describe the components of blood and discuss their functions.

3.List the formed elements of blood and discuss their functions.

4.Discuss the origin and significance of sickle cell anemia in the world.

5.Outline the formation of erythrocytes, leukocytes, and thrombocytes from the stem cell hemocytoblast.

6.Discuss how blood doping could be dangerous.

7.List the different leukocytes and describe their functions.

8.Describe in detail the ABO blood group system and discuss its significance.

9.Discuss the physiological significance of the Rh system.

10.List the major components of blood plasma.

11.Outline the basic mechanism of blood clotting.

LANGUAGE OF SCIENCE AND MEDICINE

Before reading the chapter, say each of these terms out loud. This will help you avoid stumbling over them as you read.

agglutinate

(ah-GLOO-tin-ayt) [agglutin- glue, -ate process]

agranulocyte

(ah-GRAN-yoo-loh-syte) [a- without, -gran- grain, -ul- little, -cyte cell]

anemia

(ah-NEE-mee-ah) [an- without, -emia blood condition]

anticoagulant drug

(an-tee-koh-AG-yoo-lant) [anti- against, -coagul- curdle, -ant agent]

antigen

(AN-tih-jen) [anti- against, -gen produce]

antigen A

(AN-tih-jen) [anti- against, -gen produce]

antigen B

(AN-tih-jen) [anti- against, -gen produce]

antiplatelet drug

(an-tee-PLAYT-let) [anti- against, -plate- flat, -let small]

basophil

(BAY-soh-fil) [bas- foundation, -phil love]

blood boosting

blood doping

blood serum

(SEER-um) [serum watery fluid] pl., sera (SEER-ah)

blood type

[tupos- impression]

B lymphocyte

(B LIM-foh-syte) [B bursa-equivalent tissue, lympho- the lymph, -cyte cell]

coagulation

(koh-ag-yoo-LAY-shun) [coagul- curdle, -ation process]

complete blood cell count

(CBC)

coumarin

(KOO-mar-in) [coumarou- tonka bean tree]

diapedesis

(dye-ah-peh-DEE-sis) [dia- apart or through, -pedesis oozing]

differential white blood cell (WBC) count

(dif-er-EN-shal)

electrolyte

(eh-LEK-troh-lyte) [electro- electricity, -lyt- loosening]

eosinophil

(ee-oh-SIN-oh-fil) [eosin- reddish color, -phil love]

erythroblastosis fetalis

(eh-rith-roh-blas-TOH-sis feh-TAL-is) [erythro- red, -blast- bud, -osis condition]

erythrocyte

(eh-RITH-roh-syte) [erythro- red, -cyte cell]

erythropoiesis

(eh-rith-roh-poy-EE-sis) [erythro- red, -poiesis making]

erythropoietin (EPO)

(eh-rith-roh-POY-eh-tin) [erythro- red, -poiet- make, -in substance]

extrinsic pathway

(eks-TRIN-sik PATH-way) [extr- outside, -sic beside]

fibrinolysis

(fye-brin-OL-ih-sis) [fibr- fiber, -lysis loosening]

formed element

(EL-em-ent)

globin

(GLOH-bin) [glob- ball, -in substance]

granulocyte

(GRAN-yoo-loh-syte) [gran- grain, -ul- little, -cyte cell]

hematocrit

(hee-MAT-oh-krit) [hemato- blood, -crit separate]

hemocytoblast

(hee-moh-SYE-toh-blast) [hemo- blood, -cyto- cell, -blast embryonic state of development]

hemoglobin

(hee-moh-GLOH-bin) [hem- blood, -globus ball]

hemolysis

(hee-MAHL-ih-sis) [hemo- blood, -lysis loosening]

hemostasis

(hee-moh-STAY-sis) [hemo- blood, -stasis standing]

heparin

(HEP-ah-rin) [hepar- liver, -in substance]

intrinsic pathway

(in-TRIN-sik) [intr- within, -sic beside]

leukocyte

(LOO-koh-syte) [leuko- white, -cyte cell]

leukocytosis

(loo-koh-sye-TOH-sis) [leuko- white, -cyt- cell, -osis condition]

leukopenia

(loo-koh-PEE-nee-ah) [leuko- white, -penia lack]

lymphocyte

(LIM-foh-syte) [lymph- water (lymphatic system), -cyte cell]

monocyte

(MON-oh-syte) [mono- single, -cyte cell]

myeloid tissue

(MY-eh-loyd TISH-yoo) [myel- marrow, -oid like, tissue- fabric]

neutrophil

(NOO-troh-fil) [neuter- neither, -phil love]

nonelectrolyte

(non-ee-LEK-troh-lyte) [non- not, -electro- electricity, -lyt- loosening]

physiological polycythemia

(fiz-ee-oh-LOJ-ih-kal pol-ee-sye-THEE-mee-ah) [physi- nature, -o- combining form, -log- words (study of), -y activity, poly- many, -cyt- cell, -emia blood condition]

plasma

(PLAZ-mah) [plasma substance]

plasminogen

(plaz-MIN-oh-jen) [plasm- substance (plasma), -in- substance, -gen produce]

platelet

(PLAYT-let) [plate- flat, -let small]

platelet plug

(PLAYT-let) [plate- flat, -let small]

prothrombin

(pro-THROM-bin) [pro- first, -thromb- clot, -in substance]

Rh antigen

(R-H AN-tih-jen) [Rh Rhesus (monkey), anti- against, -gen produce]

streptokinase

(strep-toh-KIN-ayz) [strepto- twisted, -kin- motion, -ase enzyme]

thrombopoiesis

(throm-boh-poy-EE-sis) [thromb- clot, -poiesis making]

thrombosis

(throm-BOH-sis) [thromb- clot, -osis condition]

T lymphocyte

(LIM-foh-syte) [T thymus gland, lymph- water (lymphatic system), -cyte cell]

transfusion reaction

(tranz-FYOO-zhun ree-AK-shun) [trans- across, -fus- pour, -sion process, re- again, -action action]

whole blood volume

DUNCAN was slicing a bagel to put in the toaster. When the microwave beeped, he glanced in that direction, taking his eyes off the bagel. In that split second, the knife slipped and cut deeply into his finger. Immediately blood started spurting out of the damaged blood vessels. Duncan grabbed a towel and wrapped it tightly around the cut while holding his hand above his heart.

We’ve all done something similar by not paying attention, but did you ever wonder about all the complex physical and physiological processes that take place immediately after we cut ourselves? In this chapter, as you follow Duncan’s story, you’ll find out what really happens.

Now that you have read this chapter, try to answer these questions about Duncan’s cut from the Introductory Story.

1. What is the main component of the blood coming out of Duncan’s finger?

a. Erythrocytes

b. Leukocytes

c. Plasma

d. Thrombocytes

Because of the damage to his blood vessels, Duncan’s body will immediately start the blood clotting process.

2. What’s the first step in hemostasis (stopping bleeding)?

a. Vascular spasm

b. Platelet plug

c. Coagulation

d. Leukocytic plug

3. What is the last step in clot formation?

a. Fibrinogen converted to fibrin

b. Prothrombin converted to thrombin

c. Profibrin converted to fibrin

d. Collagen fibers trap RBCs

4. If Duncan were missing factor VIII, what condition would he have?

a. Thrombocytopenia

b. Pernicious anemia

c. Polycythemia

d. Hemophilia

To solve a case study, you may have to refer to the glossary or index, other chapters in this textbook, A&P Connect, Mechanisms of Disease, and other resources.

You have undoubtedly seen blood, but have you ever wondered about its properties? Blood is a wonderfully fluid transport medium that serves as a pickup and delivery system that services the entire body. For example, it picks up food and oxygen from the digestive and respiratory systems and delivers these vital elements to the cells throughout the body. At the same time it picks up wastes from cells for delivery to excretory organs. But blood does more than this. It also transports hormones, enzymes, buffers, and other important biochemicals. Finally, the flow of blood is vital to temperature regulation in our bodies. Blood exhibits a physical property called specific heat, which allows it to absorb heat energy while at the same time resisting significant temperature change. This property permits blood temperature to remain relatively constant and within very narrow limits even when burdened with a signifcant heat load. Because of its high specific heat, blood can efficiently absorb and then safely transfer large amounts of heat energy from metabolism to the body’s surface where it is dissipated by evaporation, convection, and radiation to the environment (see box on p. 127 for a review of this process).

BLOOD COMPOSITION

First and foremost, blood is a liquid connective tissue consisting not only of fluid plasma, but also of cells. Plasma is the third major fluid in our bodies (the other two are the interstitial fluids and intracellular fluids). Our blood volume is often expressed as a percentage of our total body weight. However, the measurement of the plasma and formed elements is typically expressed as a percentage of the whole blood volume. Using this method, whole blood is equal to about 8% of total body weight. Plasma accounts for 55% and formed elements such as various blood cells account for 45% of the total volume (Figure 16-1).

Blood Volume

Males have about 5 to 6 liters of blood circulating in their bodies and females have about 4 to 5 liters. In addition to gender differences, blood volume varies with age and body composition. A unit of blood (about 0.5 liter or 1 pint)

FIGURE 16-1 Composition of whole blood. Approximate values for the components of blood in a normal adult.

is the amount collected from blood donors for blood transfusion. One unit is equal to about 10% of the total blood volume for an average adult. There are several methods of measuring blood volume. Regardless of which method is used, it is important to have an accurate measurement in case blood volume must be replaced for a variety of conditions, including hemorrhage and shock.

One of the most important variables influencing blood volume is the amount of body fat. Blood volume per kilogram of body weight varies inversely with the amount of excess body fat. This means that leaner people have more blood per kilogram of body weight than obese people. Because females typically have somewhat more body fat than males (per kilogram of weight), they have slightly lower blood volumes.

FORMED ELEMENTS OF BLOOD

As you can see from Figure 16-1, blood consists of about 55% plasma and 45% of a variety of formed elements. These include erythrocytes (red blood cells or RBCs), thrombocytes (platelets), and leukocytes (white blood cells or WBCs). The leukocytes are further broken down into granular leukocytes, whose cytoplasm appears granular, and nongranular leukocytes, whose cytoplasm lacks granular components (Table 16-1).

In Figure 16-2, A, you see the results of centrifuging whole blood (spinning a vial at a high rate of speed). The lighter

FIGURE 16-2 Hematocrit tubes showing normal blood, anemia, and polycythemia. Note the buffy coat located between the packed RBCs and the plasma. A, A normal percentage of red blood cells. B, Anemia (a low percentage of red blood cells). C, Polycythemia (a high percentage of red blood cells).

plasma remains at the top, and the middle-weight leukocytes and platelets form a so-called buffy coat in the middle. Erythrocytes are heavier and concentrate at the bottom of the test tube. The volume of packed red blood cells at the bottom of the test tube is called the hematocrit.

TABLE 16-1 Classes of Blood Cells

CELL TYPE

DESCRIPTION

FUNCTION

LIFE SPAN

Red Blood Cells

Erythrocyte

7 microns (μm) in diameter; concave disk shape; entire cell stains pale pink; no nucleus

Transportation of respiratory gases (O2 and some CO2)

105-120 days

Granular White Blood Cells

Neutrophil

12-1 5 μm in diameter; spherical shape; multilobed nucleus; small, pink–purple–staining cytoplasmic granules

Cellular defense–phagocytosis of small pathogenic microorganisms such as bacteria

Hours to 3 days

Basophil

11-14 (μm in diameter; spherical shape; generally two-lobed nucleus; large purple-staining cytoplasmic granules

Secretes heparin (anticoagulant) and histamine important in the inflammatory response)

Hours to 3 days

Eosinophil

10-12 μm in diameter; spherical shape; generally two-lobed nucleus; large, orange–red-staining cytoplasmic granule

Cellular defense-phagocytosis of large pathogenic microorganisms, such as protozoa and parasites; releases anti-inflammatory substances in allergic reactions

10-12 days

Nongranular White Blood Cells

Lymphocyte

6-9 μm in diameter; spherical shape; round (single-lobed) nucleus; small lymphocytes have scant cytoplasm

Humoral defense–secretes antibodies; involved in immune system response and regulation

Days to years

Monocyte

12-17 μm in diameter; spherical shape; nucleus generally kidney bean or horseshoe shaped with convoluted surface; ample cytoplasm often “steel blue” in color

Capable of migrating out ofthe blood to entertissue spaces as a macrophage–an aggressive phagocytic cell capable of ingesting bacteria, cellular debris, and cancerous cells

Months

Platelets

Thrombocyte

2-5 μm in diameter; irregularly shaped fragments; cytoplasm contains very small, pink-staining granules

Releases clot-activating substances and helps in formation of actual blood clot by forming platelet “plugs”

7-10 days

Average hematocrits vary but are normally around 45% for men and 42% for women. Conditions that result in decreased RBC numbers (Figure 16-2, B) are anemias. A reduced hematocrit number characterizes these disorders. However, healthy individuals living and working in high altitudes may have elevated RBC numbers and hematocrit values—a condition called physiological polycythemia (Figure 16-2, C).

Note that leukocytes and platelets make up less than 1% of blood volume.

1. What is the fluid portion of whole blood?

2. What constitutes the formed elements of whole blood?

3. What factors might influence blood volume?

4. What are the average component percentages of a normal hematocrit?

Red Blood Cells (Erythrocytes)

A normal, mature erythrocyte (RBC) is only about 7.5 μm in diameter. Amazingly, more than 1,500 of them can fit side by side in a 1-cm space. Before the cell reaches maturity in the bone marrow, it loses its nucleus. Unlike other cells, it also loses its ribosomes, mitochondria, and other organelles. In their place, nearly 35% of its volume is filled with hemoglobin, the protein responsible for transporting oxygen in the blood.

As you can see in Figure 16-3, erythrocytes are shaped like tiny biconcave disks. The microscopic depression on each flat surface of the cell creates a cell with a thin center and thicker edges. This unique shape gives an erythrocyte a very large surface area relative to its volume. RBCs can passively change their shapes as they are forced through capillaries under pressure. This ability is vital to the survival of RBCs, which are under almost constant mechanical stress and strain as they rush through the capillaries of our bodies. Their shape also allows faster blood flow throughout the circulatory system.

RBCs are the most numerous of all the formed elements of blood. In men, RBC counts average about 5.5 million per

FIGURE 16-3 Erythrocytes. Color-enhanced scanning electron micrograph shows normal erythrocytes. Note the biconcave shape.

cubic millimeter (mm3) of blood. In contrast, women have about 4.8 million/mm3.

Function of Red Blood Cells

RBCs play a critical role in the transport of oxygen and carbon dioxide in the body (this topic is discussed more fully in Chapter 18).

Altogether, the total surface area of all the RBCs in an adult is equivalent to an area larger than a football field. This is an enormous area for the efficient exchange of the respiratory gases between the RBCs (via their hemoglobin) and the interstitial fluid that bathes our body cells. (This is yet another excellent example of the relationship between form and function.)

Hemoglobin

Within each RBC are an estimated 200 to 300 million molecules of hemoglobin. Hemoglobin molecules are composed of four protein chains, each called a globin. Every globin molecule is bound to a heme group, each of which contains one atom of iron. This means that each hemoglobin molecule contains four iron atoms. Because of this arrangement, one hemoglobin molecule chemically bonds with four oxygen molecules to form oxyhemoglobin. This is a reversible reaction. Hemoglobin can also combine with carbon dioxide to form carbaminohemoglobin (also reversible). However, in this reaction, it is the globins, not the heme groups, that allow carbon dioxide to bond.

As we’ve seen, a man’s blood usually contains more RBCs (and thus more hemoglobin) than a woman’s blood. This is because higher levels of testosterone in men tend to stimulate erythrocyte production and cause an increase in RBC numbers. Normally, a man has 14 to 16 grams of hemoglobin for every 100 milliliters of blood in his system. An adult male who has a hemoglobin content of less than 10 g/100 ml of blood is diagnosed as having anemia (literally, a lack of blood). The term anemia is also used to describe a low RBC count. Anemias are classified according to the size and hemoglobin content of RBCs. Box 16-1 describes a specific type of anemia—sickle cell anemia—that is caused by the production of an abnormal type of hemoglobin due to a genetic error.

Formation of Red Blood Cells

The term erythropoiesis describes the entire process of RBC formation. Erythrocytes begin their maturation process in the red bone marrow from nucleated hematopoietic stem cells called hemocytoblasts (Figure 16-4). These adult stem cells have the ability to maintain a constant population of newly differentiating cells of a specific type. Note, however, that adult stem cells are not the same as embryonic stem cells (see Chapter 26), which are involved in embryonic and fetal development. Adult blood-forming stem cells divide by mitosis. Some of the daughter cells remain as undifferentiated adult stem cells. Others continue to develop into erythrocytes. You can follow this transformation in Figure 16-4.

FIGURE 16-4 Formation of blood cells. The hematopoietic stem cell, called the hemocytoblast, serves as the original stem cell from which all formed elements of the blood are derived. Note that all five precursor cells, which ultimately produce the different components of the formed elements, are derived from the hemocytoblast.

The entire maturation process requires about 4 days, after which the maturing cells lose their nuclei and become reticulocytes. Once released into the circulating blood, reticulocytes mature into erythrocytes in about a day. You should note in Figure 16-4 that overall cell size decreases as development proceeds from the stem cells to the mature erythrocytes.

Erythrocytes are formed and destroyed at a breathtaking rate. Normally, every day of our adult lives, more than 200 billion RBCs are formed to replace an equal number destroyed during that brief time. The number of RBCs remains relatively constant because efficient mechanisms maintain homeostasis. However, the rate of RBC production soon speeds up if blood oxygen levels in the tissues decline. Low oxygen level in the blood increases the secretion of a glycoprotein hormone called erythropoietin or EPO. If oxygen levels decrease, the kidneys release increasing amounts of erythropoietin. In turn, this stimulates bone marrow to accelerate its production of red blood cells. As more red blood cells increase the oxygen levels of the cells, a negative feedback system causes less erythropoietin to be produced. As a result, the production of RBCs falls back to normal. Figure 16-5 shows you how this negative feedback system works. Box 16-2 explores the controversial topic of “blood doping” sometimes used by athletes to enhance their performance.

BOX 16-1 FYI

Sickle Cell Anemia

Sickle cell anemia is a severe, sometimes fatal, hereditary disease characterized by an abnormal type of hemoglobin. A person who inherits only one defective gene develops a form of the disease called sickle cell trait. In these cases, red blood cells contain a small proportion of a hemoglobin type that is less soluble than normal. This abnormal hemoglobin forms solid crystals when the blood oxygen level is low, causing distortion and fragility of the red blood cell. If two defective genes are inherited (one from each parent), more of the defective hemoglobin is produced, and the distortion of red blood cells becomes even more severe. In the United States, about 1 in every 500 African-American and 1 in every 1,000 Hispanic newborns are affected each year. In these individuals, the distorted red blood cell walls can be damaged by drastic changes in shape. Red blood cells damaged in this way tend to stick to vessel walls. If a blood vessel in the brain is affected, a stroke may occur because of the decrease in blood flow velocity or the complete blockage of blood flow.

Stroke is one of the most devastating problems associated with sickle cell anemia in children and will affect about 10% of the 2,500 youngsters who have the disease in the United States. Studies have shown that frequent blood transfusions in addition to standard care can dramatically reduce the risk of stroke in many children suffering from sickle cell anemia. The illustration shows the characteristic shape of a red cell containing the abnormal hemoglobin.

Sickle cell anemia.

FIGURE 16-5 Erythropoiesis. In response to decreased blood oxygen, the kidneys release erythropoietin (EPO). This stimulates erythrocyte production in the red bone marrow.

BOX 16-2 Sports & Fitness

Blood Doping

Reports that some Olympic and other elite athletes use transfusions of their own blood to improve performance have surfaced repeatedly in the past several decades. The practice—called blood doping or blood boosting—is intended to increase oxygen delivery to muscles. A few weeks before competition, blood is drawn from the athlete and the red blood cells (RBCs) are separated and frozen. Just before competition, the RBCs are thawed and injected. Theoretically, infused RBCs and elevation of hemoglobin levels after transfusion should increase oxygen consumption and muscle performance during exercise. In practice, however, the advantage appears to be minimal. All blood transfusions carry some risk, and unnecessary or questionably indicated transfusions are medically and ethically unacceptable.

In addition to blood transfusions, injection of substances that increase RBC levels in an attempt to improve athletic performance has also been condemned by leading authorities in the area of sports medicine and by athletic organizations around the world. “Doping” with either the naturally occurring hormone erythropoietin (EPO) or with synthetic drugs that have similar biological effects—such as Epogen and Procrit—can result in devastating medical outcomes. For example, EPO abuse can produce dangerously high blood pressure that may lead to a heart attack or stroke.

Destruction of Red Blood Cells

The life span of RBCs circulating in the bloodstream averages between 105 and 120 days. They often break apart, or fragment, in the capillaries as they age. Macrophage cells in the lining of the blood vessels, especially those in the liver and spleen, phagocytose (ingest and destroy) the aged, abnormal, or fragmented RBCs. This process results in the breakdown of hemoglobin. As a result, amino acids, iron, and the pigment bilirubin are released into the bloodstream. Iron is returned to the bone marrow for use in the synthesis of new hemoglobin. Bilirubin is transported to the liver, where it is excreted as part of bile. Amino acids, released from the globin part of the hemoglobin, are reused by the body for energy or for the synthesis of new proteins.

For the RBC homeostatic mechanism to succeed in maintaining a normal number of RBCs, the bone marrow must function properly. To do this, the blood must supply it with the proper building components and catalysts with which to create new RBCs. In addition, the gastric mucosa of the stomach must provide intrinsic factor and perhaps other undiscovered factors necessary for the absorption of vitamin B12. This vitamin is vital to the formation of new erythrocytes.

5. What are the components of hemoglobin?

6. How many molecules of hemoglobin are in the average RBC?

7. Trace the formation of a mature erythrocyte from its stem cell precursor.

8. Explain the negative feedback loop that controls erythropoiesis.

White Blood Cells (Leukocytes)

There are five basic types of white blood cells, or leukocytes. They are classified according to the presence or absence of granules as well as the staining characteristics of their cytoplasm. Granulocytes include the three types of WBCs that have granules in their cytoplasm. They are named according to their cytoplasmic staining properties: basophils, neutrophils, and eosinophils. There are two types of agranulocytes (WBCs without cytoplasmic granules): lymphocytes and monocytes.

As a group, the leukocytes appear brightly colored in stained preparations. In addition, they all have nuclei and are generally larger than RBCs. Before continuing with the following discussion of each type, please look at Table 16-1 and briefly familiarize yourself with each cell type, its description, and function.

Granulocytes

Neutrophils

The cytoplasmic granules of neutrophils (Figure 16-6) stain a light purple with neutral dyes. The granules in these cells are small and numerous. They tend to give the cytoplasm a coarse appearance. The cytoplasmic granules contain powerful lysosomes that allow them to destroy most bacterial cells.

Neutrophils make up about 65% of the WBC count in a normal blood sample. They are highly mobile, active phagocytic cells that can migrate out of blood vessels and enter into the tissue spaces. This process is called diapedesis. It is vital to the body’s fight against invading bacteria. It works like this: Bacterial infections produce an inflammatory response. In this process, damaged cells of the body release chemicals that attract neutrophils and other phagocytic WBCs to the infection site. The swelling, pain, and heat from the infection site are indications that the battle is underway.

FIGURE 16-6 Neutrophil.

FIGURE 16-7 Eosinophil.

Eosinophils

Eosinophils (Figure 16-7) contain many large cytoplasmic granules that stain orange with acid dyes such as eosin. Their nuclei generally have just two lobes. Eosinophils equal about 2% to 5% of circulating WBCs. They are abundant in the linings of the respiratory and digestive tracts. Eosinophils can ingest inflammatory chemicals and proteins associated with antigen-antibody reaction complexes. Perhaps their most important functions involve protection against infections caused by parasitic worms. They are also involved in allergic reactions, as we shall see in Chapter 19.

Basophils

Basophils (Figure 16-8) have few, but relatively large, cytoplasmic granules that stain dark purple with basic dyes. The cytoplasmic granules of basophils contain histamine (an inflammatory chemical) and heparin (an anticoagulant). Basophils have indistinct, S-shaped nuclei. They are the least numerous of the WBCs, numbering only 0.5% to 1% of the total leukocyte count. Like neutrophils, basophils are both mobile and capable of diapedesis.

FIGURE 16-8 Basophil.

Agranulocytes

Lymphocytes

Lymphocytes (Figure 16-9) are the smallest of the leukocytes, averaging only about 6 to 9 μm in diameter. They have large, spherical nuclei surrounded by a small amount of cytoplasm that stains a pale blue. After neutrophils, lymphocytes are the most numerous WBCs. They account for about 25% of all the leukocytes in our bodies.

There are two general types of lymphocytes: T lymphocytes and B lymphocytes. Both forms have important roles in our immunity. T lymphocytes function by directly attacking an infected or cancerous cell. B lymphocytes, in contrast, produce antibodies against specific antigens.

FIGURE 16-9 Lymphocyte.

Monocytes

Monocytes (Figure 16-10) are the largest of the leukocytes. They have dark, kidney bean–shaped nuclei surrounded by large quantities of distinctive blue-gray cytoplasm. Monocytes are mobile and highly phagocytic: They can engulf large bacterial organisms and virus-infected cells.

FIGURE 16-10 Monocyte.

BOX 16-3 Diagnostic Study

Complete Blood Cell Count

One of the most useful and frequently performed clinical blood tests is called the complete blood cell count or simply the CBC. The CBC is a collection of tests whose results, when interpreted as a whole, can yield an enormous amount of information regarding a person’s health. Standard red blood cell, white blood cell, and thrombocyte counts, the differential white blood cell count, hematocrit, hemoglobin content, and other characteristics of the formed elements are usually included in this battery of tests.

White Blood Cell Numbers

Compared to erythrocytes, leukocytes are relatively rare. One cubic millimeter of normal blood usually contains only about 5,000 to 9,000 leukocytes. As we’ve seen, there are different percentages of each type. These numbers have clinical significance because they may change drastically under abnormal conditions such as infections or specific blood cancers. In acute appendicitis, for example, the percentage of neutrophils increases dramatically. So does the total WBC count. In fact, these characteristic changes may be deciding points for surgery to remove the infected organ.

An overall decrease in the number of WBCs is called leukopenia. An increase in the number of WBCs is leukocytosis. The number of each type of white blood cell can be determined by a differential white blood cell (WBC) count. In this special count (Table 16-2), the proportion of each type of white blood cell is reported as a percentage of the total WBC count. Because all disorders do not affect each type of WBC the same way, the differential WBC count is a valuable diagnostic tool. For example, some parasite infestations do not cause an increase in the total WBC count. However, they often do cause an increase in the proportion of eosinophils. Why? Because this type of WBC specializes in fighting large parasites such as parasitic nematode “worms.” Table 16-2 presents a differential count of the major white blood cell types in the blood of an average person.

Formation of White Blood Cells

Hematopoietic stem cells serve as the precursors not only of erythrocytes, but also of leukocytes and platelets. Refer to Figure 16-4 again and follow the formation and maturation of the various leukocytes from the precursor hematopoietic stem cells (hemocytoblasts). Like erythrocytes, neutrophils, eosinophils, basophils, and a few lymphocytes and monocytes originate in red bone marrow (myeloid tissue). However, note that most lymphocytes and monocytes are derived from hematopoietic adult stem cells in lymphatic tissue. So although many lymphocytes are found in bone marrow, most are formed in lymphatic tissue and later carried to the bone marrow by the bloodstream.

TABLE 16-2 Differential Count of White Blood Cells

DIFFERENTIAL COUNT*

CLASS

NORMAL RANGE (%)

TYPI CAL VALU E (%)†

Neutrophils

65–75

65

Lymphocytes (large and small)

20–25

25

Monocytes

0–3

6

Eosinophils

0–2

3

Baso

Anatomy homework help

CHAPTER 16 Blood

STUDENT LEARNING OBJECTIVES

At the completion of this chapter, you should be able to do the following:

1.Summarize the basic functions of blood.

2.Describe the components of blood and discuss their functions.

3.List the formed elements of blood and discuss their functions.

4.Discuss the origin and significance of sickle cell anemia in the world.

5.Outline the formation of erythrocytes, leukocytes, and thrombocytes from the stem cell hemocytoblast.

6.Discuss how blood doping could be dangerous.

7.List the different leukocytes and describe their functions.

8.Describe in detail the ABO blood group system and discuss its significance.

9.Discuss the physiological significance of the Rh system.

10.List the major components of blood plasma.

11.Outline the basic mechanism of blood clotting.

LANGUAGE OF SCIENCE AND MEDICINE

Before reading the chapter, say each of these terms out loud. This will help you avoid stumbling over them as you read.

agglutinate

(ah-GLOO-tin-ayt) [agglutin- glue, -ate process]

agranulocyte

(ah-GRAN-yoo-loh-syte) [a- without, -gran- grain, -ul- little, -cyte cell]

anemia

(ah-NEE-mee-ah) [an- without, -emia blood condition]

anticoagulant drug

(an-tee-koh-AG-yoo-lant) [anti- against, -coagul- curdle, -ant agent]

antigen

(AN-tih-jen) [anti- against, -gen produce]

antigen A

(AN-tih-jen) [anti- against, -gen produce]

antigen B

(AN-tih-jen) [anti- against, -gen produce]

antiplatelet drug

(an-tee-PLAYT-let) [anti- against, -plate- flat, -let small]

basophil

(BAY-soh-fil) [bas- foundation, -phil love]

blood boosting

blood doping

blood serum

(SEER-um) [serum watery fluid] pl., sera (SEER-ah)

blood type

[tupos- impression]

B lymphocyte

(B LIM-foh-syte) [B bursa-equivalent tissue, lympho- the lymph, -cyte cell]

coagulation

(koh-ag-yoo-LAY-shun) [coagul- curdle, -ation process]

complete blood cell count

(CBC)

coumarin

(KOO-mar-in) [coumarou- tonka bean tree]

diapedesis

(dye-ah-peh-DEE-sis) [dia- apart or through, -pedesis oozing]

differential white blood cell (WBC) count

(dif-er-EN-shal)

electrolyte

(eh-LEK-troh-lyte) [electro- electricity, -lyt- loosening]

eosinophil

(ee-oh-SIN-oh-fil) [eosin- reddish color, -phil love]

erythroblastosis fetalis

(eh-rith-roh-blas-TOH-sis feh-TAL-is) [erythro- red, -blast- bud, -osis condition]

erythrocyte

(eh-RITH-roh-syte) [erythro- red, -cyte cell]

erythropoiesis

(eh-rith-roh-poy-EE-sis) [erythro- red, -poiesis making]

erythropoietin (EPO)

(eh-rith-roh-POY-eh-tin) [erythro- red, -poiet- make, -in substance]

extrinsic pathway

(eks-TRIN-sik PATH-way) [extr- outside, -sic beside]

fibrinolysis

(fye-brin-OL-ih-sis) [fibr- fiber, -lysis loosening]

formed element

(EL-em-ent)

globin

(GLOH-bin) [glob- ball, -in substance]

granulocyte

(GRAN-yoo-loh-syte) [gran- grain, -ul- little, -cyte cell]

hematocrit

(hee-MAT-oh-krit) [hemato- blood, -crit separate]

hemocytoblast

(hee-moh-SYE-toh-blast) [hemo- blood, -cyto- cell, -blast embryonic state of development]

hemoglobin

(hee-moh-GLOH-bin) [hem- blood, -globus ball]

hemolysis

(hee-MAHL-ih-sis) [hemo- blood, -lysis loosening]

hemostasis

(hee-moh-STAY-sis) [hemo- blood, -stasis standing]

heparin

(HEP-ah-rin) [hepar- liver, -in substance]

intrinsic pathway

(in-TRIN-sik) [intr- within, -sic beside]

leukocyte

(LOO-koh-syte) [leuko- white, -cyte cell]

leukocytosis

(loo-koh-sye-TOH-sis) [leuko- white, -cyt- cell, -osis condition]

leukopenia

(loo-koh-PEE-nee-ah) [leuko- white, -penia lack]

lymphocyte

(LIM-foh-syte) [lymph- water (lymphatic system), -cyte cell]

monocyte

(MON-oh-syte) [mono- single, -cyte cell]

myeloid tissue

(MY-eh-loyd TISH-yoo) [myel- marrow, -oid like, tissue- fabric]

neutrophil

(NOO-troh-fil) [neuter- neither, -phil love]

nonelectrolyte

(non-ee-LEK-troh-lyte) [non- not, -electro- electricity, -lyt- loosening]

physiological polycythemia

(fiz-ee-oh-LOJ-ih-kal pol-ee-sye-THEE-mee-ah) [physi- nature, -o- combining form, -log- words (study of), -y activity, poly- many, -cyt- cell, -emia blood condition]

plasma

(PLAZ-mah) [plasma substance]

plasminogen

(plaz-MIN-oh-jen) [plasm- substance (plasma), -in- substance, -gen produce]

platelet

(PLAYT-let) [plate- flat, -let small]

platelet plug

(PLAYT-let) [plate- flat, -let small]

prothrombin

(pro-THROM-bin) [pro- first, -thromb- clot, -in substance]

Rh antigen

(R-H AN-tih-jen) [Rh Rhesus (monkey), anti- against, -gen produce]

streptokinase

(strep-toh-KIN-ayz) [strepto- twisted, -kin- motion, -ase enzyme]

thrombopoiesis

(throm-boh-poy-EE-sis) [thromb- clot, -poiesis making]

thrombosis

(throm-BOH-sis) [thromb- clot, -osis condition]

T lymphocyte

(LIM-foh-syte) [T thymus gland, lymph- water (lymphatic system), -cyte cell]

transfusion reaction

(tranz-FYOO-zhun ree-AK-shun) [trans- across, -fus- pour, -sion process, re- again, -action action]

whole blood volume

DUNCAN was slicing a bagel to put in the toaster. When the microwave beeped, he glanced in that direction, taking his eyes off the bagel. In that split second, the knife slipped and cut deeply into his finger. Immediately blood started spurting out of the damaged blood vessels. Duncan grabbed a towel and wrapped it tightly around the cut while holding his hand above his heart.

We’ve all done something similar by not paying attention, but did you ever wonder about all the complex physical and physiological processes that take place immediately after we cut ourselves? In this chapter, as you follow Duncan’s story, you’ll find out what really happens.

Now that you have read this chapter, try to answer these questions about Duncan’s cut from the Introductory Story.

1. What is the main component of the blood coming out of Duncan’s finger?

a. Erythrocytes

b. Leukocytes

c. Plasma

d. Thrombocytes

Because of the damage to his blood vessels, Duncan’s body will immediately start the blood clotting process.

2. What’s the first step in hemostasis (stopping bleeding)?

a. Vascular spasm

b. Platelet plug

c. Coagulation

d. Leukocytic plug

3. What is the last step in clot formation?

a. Fibrinogen converted to fibrin

b. Prothrombin converted to thrombin

c. Profibrin converted to fibrin

d. Collagen fibers trap RBCs

4. If Duncan were missing factor VIII, what condition would he have?

a. Thrombocytopenia

b. Pernicious anemia

c. Polycythemia

d. Hemophilia

To solve a case study, you may have to refer to the glossary or index, other chapters in this textbook, A&P Connect, Mechanisms of Disease, and other resources.

You have undoubtedly seen blood, but have you ever wondered about its properties? Blood is a wonderfully fluid transport medium that serves as a pickup and delivery system that services the entire body. For example, it picks up food and oxygen from the digestive and respiratory systems and delivers these vital elements to the cells throughout the body. At the same time it picks up wastes from cells for delivery to excretory organs. But blood does more than this. It also transports hormones, enzymes, buffers, and other important biochemicals. Finally, the flow of blood is vital to temperature regulation in our bodies. Blood exhibits a physical property called specific heat, which allows it to absorb heat energy while at the same time resisting significant temperature change. This property permits blood temperature to remain relatively constant and within very narrow limits even when burdened with a signifcant heat load. Because of its high specific heat, blood can efficiently absorb and then safely transfer large amounts of heat energy from metabolism to the body’s surface where it is dissipated by evaporation, convection, and radiation to the environment (see box on p. 127 for a review of this process).

BLOOD COMPOSITION

First and foremost, blood is a liquid connective tissue consisting not only of fluid plasma, but also of cells. Plasma is the third major fluid in our bodies (the other two are the interstitial fluids and intracellular fluids). Our blood volume is often expressed as a percentage of our total body weight. However, the measurement of the plasma and formed elements is typically expressed as a percentage of the whole blood volume. Using this method, whole blood is equal to about 8% of total body weight. Plasma accounts for 55% and formed elements such as various blood cells account for 45% of the total volume (Figure 16-1).

Blood Volume

Males have about 5 to 6 liters of blood circulating in their bodies and females have about 4 to 5 liters. In addition to gender differences, blood volume varies with age and body composition. A unit of blood (about 0.5 liter or 1 pint)

FIGURE 16-1 Composition of whole blood. Approximate values for the components of blood in a normal adult.

is the amount collected from blood donors for blood transfusion. One unit is equal to about 10% of the total blood volume for an average adult. There are several methods of measuring blood volume. Regardless of which method is used, it is important to have an accurate measurement in case blood volume must be replaced for a variety of conditions, including hemorrhage and shock.

One of the most important variables influencing blood volume is the amount of body fat. Blood volume per kilogram of body weight varies inversely with the amount of excess body fat. This means that leaner people have more blood per kilogram of body weight than obese people. Because females typically have somewhat more body fat than males (per kilogram of weight), they have slightly lower blood volumes.

FORMED ELEMENTS OF BLOOD

As you can see from Figure 16-1, blood consists of about 55% plasma and 45% of a variety of formed elements. These include erythrocytes (red blood cells or RBCs), thrombocytes (platelets), and leukocytes (white blood cells or WBCs). The leukocytes are further broken down into granular leukocytes, whose cytoplasm appears granular, and nongranular leukocytes, whose cytoplasm lacks granular components (Table 16-1).

In Figure 16-2, A, you see the results of centrifuging whole blood (spinning a vial at a high rate of speed). The lighter

FIGURE 16-2 Hematocrit tubes showing normal blood, anemia, and polycythemia. Note the buffy coat located between the packed RBCs and the plasma. A, A normal percentage of red blood cells. B, Anemia (a low percentage of red blood cells). C, Polycythemia (a high percentage of red blood cells).

plasma remains at the top, and the middle-weight leukocytes and platelets form a so-called buffy coat in the middle. Erythrocytes are heavier and concentrate at the bottom of the test tube. The volume of packed red blood cells at the bottom of the test tube is called the hematocrit.

TABLE 16-1 Classes of Blood Cells

CELL TYPE

DESCRIPTION

FUNCTION

LIFE SPAN

Red Blood Cells

Erythrocyte

7 microns (μm) in diameter; concave disk shape; entire cell stains pale pink; no nucleus

Transportation of respiratory gases (O2 and some CO2)

105-120 days

Granular White Blood Cells

Neutrophil

12-1 5 μm in diameter; spherical shape; multilobed nucleus; small, pink–purple–staining cytoplasmic granules

Cellular defense–phagocytosis of small pathogenic microorganisms such as bacteria

Hours to 3 days

Basophil

11-14 (μm in diameter; spherical shape; generally two-lobed nucleus; large purple-staining cytoplasmic granules

Secretes heparin (anticoagulant) and histamine important in the inflammatory response)

Hours to 3 days

Eosinophil

10-12 μm in diameter; spherical shape; generally two-lobed nucleus; large, orange–red-staining cytoplasmic granule

Cellular defense-phagocytosis of large pathogenic microorganisms, such as protozoa and parasites; releases anti-inflammatory substances in allergic reactions

10-12 days

Nongranular White Blood Cells

Lymphocyte

6-9 μm in diameter; spherical shape; round (single-lobed) nucleus; small lymphocytes have scant cytoplasm

Humoral defense–secretes antibodies; involved in immune system response and regulation

Days to years

Monocyte

12-17 μm in diameter; spherical shape; nucleus generally kidney bean or horseshoe shaped with convoluted surface; ample cytoplasm often “steel blue” in color

Capable of migrating out ofthe blood to entertissue spaces as a macrophage–an aggressive phagocytic cell capable of ingesting bacteria, cellular debris, and cancerous cells

Months

Platelets

Thrombocyte

2-5 μm in diameter; irregularly shaped fragments; cytoplasm contains very small, pink-staining granules

Releases clot-activating substances and helps in formation of actual blood clot by forming platelet “plugs”

7-10 days

Average hematocrits vary but are normally around 45% for men and 42% for women. Conditions that result in decreased RBC numbers (Figure 16-2, B) are anemias. A reduced hematocrit number characterizes these disorders. However, healthy individuals living and working in high altitudes may have elevated RBC numbers and hematocrit values—a condition called physiological polycythemia (Figure 16-2, C).

Note that leukocytes and platelets make up less than 1% of blood volume.

1. What is the fluid portion of whole blood?

2. What constitutes the formed elements of whole blood?

3. What factors might influence blood volume?

4. What are the average component percentages of a normal hematocrit?

Red Blood Cells (Erythrocytes)

A normal, mature erythrocyte (RBC) is only about 7.5 μm in diameter. Amazingly, more than 1,500 of them can fit side by side in a 1-cm space. Before the cell reaches maturity in the bone marrow, it loses its nucleus. Unlike other cells, it also loses its ribosomes, mitochondria, and other organelles. In their place, nearly 35% of its volume is filled with hemoglobin, the protein responsible for transporting oxygen in the blood.

As you can see in Figure 16-3, erythrocytes are shaped like tiny biconcave disks. The microscopic depression on each flat surface of the cell creates a cell with a thin center and thicker edges. This unique shape gives an erythrocyte a very large surface area relative to its volume. RBCs can passively change their shapes as they are forced through capillaries under pressure. This ability is vital to the survival of RBCs, which are under almost constant mechanical stress and strain as they rush through the capillaries of our bodies. Their shape also allows faster blood flow throughout the circulatory system.

RBCs are the most numerous of all the formed elements of blood. In men, RBC counts average about 5.5 million per

FIGURE 16-3 Erythrocytes. Color-enhanced scanning electron micrograph shows normal erythrocytes. Note the biconcave shape.

cubic millimeter (mm3) of blood. In contrast, women have about 4.8 million/mm3.

Function of Red Blood Cells

RBCs play a critical role in the transport of oxygen and carbon dioxide in the body (this topic is discussed more fully in Chapter 18).

Altogether, the total surface area of all the RBCs in an adult is equivalent to an area larger than a football field. This is an enormous area for the efficient exchange of the respiratory gases between the RBCs (via their hemoglobin) and the interstitial fluid that bathes our body cells. (This is yet another excellent example of the relationship between form and function.)

Hemoglobin

Within each RBC are an estimated 200 to 300 million molecules of hemoglobin. Hemoglobin molecules are composed of four protein chains, each called a globin. Every globin molecule is bound to a heme group, each of which contains one atom of iron. This means that each hemoglobin molecule contains four iron atoms. Because of this arrangement, one hemoglobin molecule chemically bonds with four oxygen molecules to form oxyhemoglobin. This is a reversible reaction. Hemoglobin can also combine with carbon dioxide to form carbaminohemoglobin (also reversible). However, in this reaction, it is the globins, not the heme groups, that allow carbon dioxide to bond.

As we’ve seen, a man’s blood usually contains more RBCs (and thus more hemoglobin) than a woman’s blood. This is because higher levels of testosterone in men tend to stimulate erythrocyte production and cause an increase in RBC numbers. Normally, a man has 14 to 16 grams of hemoglobin for every 100 milliliters of blood in his system. An adult male who has a hemoglobin content of less than 10 g/100 ml of blood is diagnosed as having anemia (literally, a lack of blood). The term anemia is also used to describe a low RBC count. Anemias are classified according to the size and hemoglobin content of RBCs. Box 16-1 describes a specific type of anemia—sickle cell anemia—that is caused by the production of an abnormal type of hemoglobin due to a genetic error.

Formation of Red Blood Cells

The term erythropoiesis describes the entire process of RBC formation. Erythrocytes begin their maturation process in the red bone marrow from nucleated hematopoietic stem cells called hemocytoblasts (Figure 16-4). These adult stem cells have the ability to maintain a constant population of newly differentiating cells of a specific type. Note, however, that adult stem cells are not the same as embryonic stem cells (see Chapter 26), which are involved in embryonic and fetal development. Adult blood-forming stem cells divide by mitosis. Some of the daughter cells remain as undifferentiated adult stem cells. Others continue to develop into erythrocytes. You can follow this transformation in Figure 16-4.

FIGURE 16-4 Formation of blood cells. The hematopoietic stem cell, called the hemocytoblast, serves as the original stem cell from which all formed elements of the blood are derived. Note that all five precursor cells, which ultimately produce the different components of the formed elements, are derived from the hemocytoblast.

The entire maturation process requires about 4 days, after which the maturing cells lose their nuclei and become reticulocytes. Once released into the circulating blood, reticulocytes mature into erythrocytes in about a day. You should note in Figure 16-4 that overall cell size decreases as development proceeds from the stem cells to the mature erythrocytes.

Erythrocytes are formed and destroyed at a breathtaking rate. Normally, every day of our adult lives, more than 200 billion RBCs are formed to replace an equal number destroyed during that brief time. The number of RBCs remains relatively constant because efficient mechanisms maintain homeostasis. However, the rate of RBC production soon speeds up if blood oxygen levels in the tissues decline. Low oxygen level in the blood increases the secretion of a glycoprotein hormone called erythropoietin or EPO. If oxygen levels decrease, the kidneys release increasing amounts of erythropoietin. In turn, this stimulates bone marrow to accelerate its production of red blood cells. As more red blood cells increase the oxygen levels of the cells, a negative feedback system causes less erythropoietin to be produced. As a result, the production of RBCs falls back to normal. Figure 16-5 shows you how this negative feedback system works. Box 16-2 explores the controversial topic of “blood doping” sometimes used by athletes to enhance their performance.

BOX 16-1 FYI

Sickle Cell Anemia

Sickle cell anemia is a severe, sometimes fatal, hereditary disease characterized by an abnormal type of hemoglobin. A person who inherits only one defective gene develops a form of the disease called sickle cell trait. In these cases, red blood cells contain a small proportion of a hemoglobin type that is less soluble than normal. This abnormal hemoglobin forms solid crystals when the blood oxygen level is low, causing distortion and fragility of the red blood cell. If two defective genes are inherited (one from each parent), more of the defective hemoglobin is produced, and the distortion of red blood cells becomes even more severe. In the United States, about 1 in every 500 African-American and 1 in every 1,000 Hispanic newborns are affected each year. In these individuals, the distorted red blood cell walls can be damaged by drastic changes in shape. Red blood cells damaged in this way tend to stick to vessel walls. If a blood vessel in the brain is affected, a stroke may occur because of the decrease in blood flow velocity or the complete blockage of blood flow.

Stroke is one of the most devastating problems associated with sickle cell anemia in children and will affect about 10% of the 2,500 youngsters who have the disease in the United States. Studies have shown that frequent blood transfusions in addition to standard care can dramatically reduce the risk of stroke in many children suffering from sickle cell anemia. The illustration shows the characteristic shape of a red cell containing the abnormal hemoglobin.

Sickle cell anemia.

FIGURE 16-5 Erythropoiesis. In response to decreased blood oxygen, the kidneys release erythropoietin (EPO). This stimulates erythrocyte production in the red bone marrow.

BOX 16-2 Sports & Fitness

Blood Doping

Reports that some Olympic and other elite athletes use transfusions of their own blood to improve performance have surfaced repeatedly in the past several decades. The practice—called blood doping or blood boosting—is intended to increase oxygen delivery to muscles. A few weeks before competition, blood is drawn from the athlete and the red blood cells (RBCs) are separated and frozen. Just before competition, the RBCs are thawed and injected. Theoretically, infused RBCs and elevation of hemoglobin levels after transfusion should increase oxygen consumption and muscle performance during exercise. In practice, however, the advantage appears to be minimal. All blood transfusions carry some risk, and unnecessary or questionably indicated transfusions are medically and ethically unacceptable.

In addition to blood transfusions, injection of substances that increase RBC levels in an attempt to improve athletic performance has also been condemned by leading authorities in the area of sports medicine and by athletic organizations around the world. “Doping” with either the naturally occurring hormone erythropoietin (EPO) or with synthetic drugs that have similar biological effects—such as Epogen and Procrit—can result in devastating medical outcomes. For example, EPO abuse can produce dangerously high blood pressure that may lead to a heart attack or stroke.

Destruction of Red Blood Cells

The life span of RBCs circulating in the bloodstream averages between 105 and 120 days. They often break apart, or fragment, in the capillaries as they age. Macrophage cells in the lining of the blood vessels, especially those in the liver and spleen, phagocytose (ingest and destroy) the aged, abnormal, or fragmented RBCs. This process results in the breakdown of hemoglobin. As a result, amino acids, iron, and the pigment bilirubin are released into the bloodstream. Iron is returned to the bone marrow for use in the synthesis of new hemoglobin. Bilirubin is transported to the liver, where it is excreted as part of bile. Amino acids, released from the globin part of the hemoglobin, are reused by the body for energy or for the synthesis of new proteins.

For the RBC homeostatic mechanism to succeed in maintaining a normal number of RBCs, the bone marrow must function properly. To do this, the blood must supply it with the proper building components and catalysts with which to create new RBCs. In addition, the gastric mucosa of the stomach must provide intrinsic factor and perhaps other undiscovered factors necessary for the absorption of vitamin B12. This vitamin is vital to the formation of new erythrocytes.

5. What are the components of hemoglobin?

6. How many molecules of hemoglobin are in the average RBC?

7. Trace the formation of a mature erythrocyte from its stem cell precursor.

8. Explain the negative feedback loop that controls erythropoiesis.

White Blood Cells (Leukocytes)

There are five basic types of white blood cells, or leukocytes. They are classified according to the presence or absence of granules as well as the staining characteristics of their cytoplasm. Granulocytes include the three types of WBCs that have granules in their cytoplasm. They are named according to their cytoplasmic staining properties: basophils, neutrophils, and eosinophils. There are two types of agranulocytes (WBCs without cytoplasmic granules): lymphocytes and monocytes.

As a group, the leukocytes appear brightly colored in stained preparations. In addition, they all have nuclei and are generally larger than RBCs. Before continuing with the following discussion of each type, please look at Table 16-1 and briefly familiarize yourself with each cell type, its description, and function.

Granulocytes

Neutrophils

The cytoplasmic granules of neutrophils (Figure 16-6) stain a light purple with neutral dyes. The granules in these cells are small and numerous. They tend to give the cytoplasm a coarse appearance. The cytoplasmic granules contain powerful lysosomes that allow them to destroy most bacterial cells.

Neutrophils make up about 65% of the WBC count in a normal blood sample. They are highly mobile, active phagocytic cells that can migrate out of blood vessels and enter into the tissue spaces. This process is called diapedesis. It is vital to the body’s fight against invading bacteria. It works like this: Bacterial infections produce an inflammatory response. In this process, damaged cells of the body release chemicals that attract neutrophils and other phagocytic WBCs to the infection site. The swelling, pain, and heat from the infection site are indications that the battle is underway.

FIGURE 16-6 Neutrophil.

FIGURE 16-7 Eosinophil.

Eosinophils

Eosinophils (Figure 16-7) contain many large cytoplasmic granules that stain orange with acid dyes such as eosin. Their nuclei generally have just two lobes. Eosinophils equal about 2% to 5% of circulating WBCs. They are abundant in the linings of the respiratory and digestive tracts. Eosinophils can ingest inflammatory chemicals and proteins associated with antigen-antibody reaction complexes. Perhaps their most important functions involve protection against infections caused by parasitic worms. They are also involved in allergic reactions, as we shall see in Chapter 19.

Basophils

Basophils (Figure 16-8) have few, but relatively large, cytoplasmic granules that stain dark purple with basic dyes. The cytoplasmic granules of basophils contain histamine (an inflammatory chemical) and heparin (an anticoagulant). Basophils have indistinct, S-shaped nuclei. They are the least numerous of the WBCs, numbering only 0.5% to 1% of the total leukocyte count. Like neutrophils, basophils are both mobile and capable of diapedesis.

FIGURE 16-8 Basophil.

Agranulocytes

Lymphocytes

Lymphocytes (Figure 16-9) are the smallest of the leukocytes, averaging only about 6 to 9 μm in diameter. They have large, spherical nuclei surrounded by a small amount of cytoplasm that stains a pale blue. After neutrophils, lymphocytes are the most numerous WBCs. They account for about 25% of all the leukocytes in our bodies.

There are two general types of lymphocytes: T lymphocytes and B lymphocytes. Both forms have important roles in our immunity. T lymphocytes function by directly attacking an infected or cancerous cell. B lymphocytes, in contrast, produce antibodies against specific antigens.

FIGURE 16-9 Lymphocyte.

Monocytes

Monocytes (Figure 16-10) are the largest of the leukocytes. They have dark, kidney bean–shaped nuclei surrounded by large quantities of distinctive blue-gray cytoplasm. Monocytes are mobile and highly phagocytic: They can engulf large bacterial organisms and virus-infected cells.

FIGURE 16-10 Monocyte.

BOX 16-3 Diagnostic Study

Complete Blood Cell Count

One of the most useful and frequently performed clinical blood tests is called the complete blood cell count or simply the CBC. The CBC is a collection of tests whose results, when interpreted as a whole, can yield an enormous amount of information regarding a person’s health. Standard red blood cell, white blood cell, and thrombocyte counts, the differential white blood cell count, hematocrit, hemoglobin content, and other characteristics of the formed elements are usually included in this battery of tests.

White Blood Cell Numbers

Compared to erythrocytes, leukocytes are relatively rare. One cubic millimeter of normal blood usually contains only about 5,000 to 9,000 leukocytes. As we’ve seen, there are different percentages of each type. These numbers have clinical significance because they may change drastically under abnormal conditions such as infections or specific blood cancers. In acute appendicitis, for example, the percentage of neutrophils increases dramatically. So does the total WBC count. In fact, these characteristic changes may be deciding points for surgery to remove the infected organ.

An overall decrease in the number of WBCs is called leukopenia. An increase in the number of WBCs is leukocytosis. The number of each type of white blood cell can be determined by a differential white blood cell (WBC) count. In this special count (Table 16-2), the proportion of each type of white blood cell is reported as a percentage of the total WBC count. Because all disorders do not affect each type of WBC the same way, the differential WBC count is a valuable diagnostic tool. For example, some parasite infestations do not cause an increase in the total WBC count. However, they often do cause an increase in the proportion of eosinophils. Why? Because this type of WBC specializes in fighting large parasites such as parasitic nematode “worms.” Table 16-2 presents a differential count of the major white blood cell types in the blood of an average person.

Formation of White Blood Cells

Hematopoietic stem cells serve as the precursors not only of erythrocytes, but also of leukocytes and platelets. Refer to Figure 16-4 again and follow the formation and maturation of the various leukocytes from the precursor hematopoietic stem cells (hemocytoblasts). Like erythrocytes, neutrophils, eosinophils, basophils, and a few lymphocytes and monocytes originate in red bone marrow (myeloid tissue). However, note that most lymphocytes and monocytes are derived from hematopoietic adult stem cells in lymphatic tissue. So although many lymphocytes are found in bone marrow, most are formed in lymphatic tissue and later carried to the bone marrow by the bloodstream.

TABLE 16-2 Differential Count of White Blood Cells

DIFFERENTIAL COUNT*

CLASS

NORMAL RANGE (%)

TYPI CAL VALU E (%)†

Neutrophils

65–75

65

Lymphocytes (large and small)

20–25

25

Monocytes

0–3

6

Eosinophils

0–2

3

Baso

Anatomy homework help

CRITICAL REVIEW EVALUATION 2022

Content & Point Value Totals

Exc.

S

U

0

Points


INTRODUCTORY PARAGRAPH

CATCH the reader’s attention and/or introduce the topic of the critical review. IDENTIFY the play (title, playwright) and where the production was presented. PROVIDE some background about this play’s origin, playwright, and the playwright’s intended objective(s) for writing this play. COMPOSE a thesis statement that indicates that this review is commentary on the director’s choices for the acting and the design, as well as the work of the designers and actors. [20 pts.]


FIRST IMPRESSIONS
HOW does the play begin? Does it provide any backstory, or set the atmosphere, or start immediately with the action of the storyline? DESCRIBE the design elements in the first scene: scenic, lighting, sound, costumes, makeup. Which design choices stand out to you—positively or negatively— and why? [20 pts.]


DESIGN
HOW realistic or theatrical are the designs? How do they impact your experience of the production? IDENTIFY, throughout the production, identify the scenic elements, costume elements, makeup, and use of lighting and sound that are most effective and/or least effective. EXPLAIN why they fit your decisions about their values. As the director has the final say on design, comment on the effectiveness (positive or negative) of each element you have highlighted; you may compliment his/her/their choices and/or question why a particular choice was made. [20 pts.]


ACTING
DESCRIBE the style of acting (realistic or stylistic). Does it fit with the design style? How does this style impact your experience of the production? As the director has the final say on the acting, comment on the effectiveness of what his/her/their choices and/or question why a particular choice was made. [20 pts.]


DIRECTING
— Considering the guidance of the director, which elements (acting or visual design) indicate the director’s choice of focus? [10 pts.]


CONCLUSION
– Give an overall statement about the elements (directing, acting, design) and how they impacted the audience experience of the production. [10 pts.]

Theatre terminology – incorrect use of terms = minus points

Writing quality – errors in spelling, lack of proofreading, fragments or run-ons, incorrect punctuation = minus points

Paper Grade

[Total of 100 points possible]


NOTES FROM THE INSTRUCTOR:

Anatomy homework help

CHAPTER 18 Physiology of the Cardiovascular System

STUDENT LEARNING OBJECTIVES

At the completion of this chapter, you should be able to do the following:

1.List the basic components of the cardiovascular system.

2.Describe the structures of the heart and how they serve to pump blood.

3.Discuss the deflection waves of a normal ECG and explain their significance.

4.Outline the basic steps of the cardiac cycle.

5.Discuss the primary principle of circulation and the significance of high arterial blood pressure.

6.Describe factors that affect stroke volume and heart rate.

7.Discuss the significance of peripheral resistance in the cardiovascular system.

8.Discuss the significance of the vasomotor control mechanism.

9.Discuss how the respiratory pump and skeletal muscle pump work to assist the venous return of blood to the heart.

10.Outline the hormonal mechanisms that regulate blood volume.

11.Discuss the significance of the pulse mechanism.

12.List several major pulse points in the body.

LANGUAGE OF SCIENCE AND MEDICINE

Before reading the chapter, say each of these terms out loud. This will help you avoid stumbling over them as you read.

ADH mechanism (A-D-H MEK-ah-nih-zem)

[ADH antidiuretic hormone, mechan- machine, -ism state]

ANH mechanism (A-N-H MEK-ah-nih-zem)

[ANH atrial natriuretic hormone, mechan- machine, -ism state]

atrioventricular (AV) bundle (ay-tree-oh-ven-TRIK-yoo-lar BUN-del)

[atrio- entrance courtyard, -ventr- belly, -icul- little, -ar relating to]

atrioventricular (AV) node (ay-tree-oh-ven-TRIK-yoo-lar)

[atrio- entrance courtyard, -ventr- belly, -icul- little, -ar relating to, nod- knot]

baroreceptor (bar-oh-ree-SEP-tor)

[baro- pressure, -recept- receive, -or agent]

cardiac cycle (KAR-dee-ak SYE-kul)

[cardi- heart, -ac relating to, cycle circle]

cardiac output (CO) (KAR-dee-ak)

[cardi- heart, -ac relating to]

conduction system of the heart (kon-DUK-shen SIS-tem)

[conduct- lead, -tion process, system organized whole]

contractility (kon-trak-TIL-ih-tee)

[con- together, -tract- drag or draw, -il- of or like, -ity quality of]

diastole (dye-ASS-toh-lee)

[dia- through, -stole contraction]

diastolic blood pressure (dye-ah-STOL-ik PRESH-ur)

[dia- apart or through, -stol- contraction, -ic relating to]

ectopic pacemaker (ek-TOP-ik PAYS-may-ker)

[ec- out of, -top- place, -ic relating to]

electrocardiogram (ECG or EKG) (eh-lek-troh-KAR-dee-oh-gram)

[electro- electricity, -cardio- heart, -gram drawing]

heart murmur

[murmur hum]

heart rate (HR)

hemodynamics (hee-moh-dye-NAM-iks)

[hemo- blood, -dynami- force, -ic relating to]

peripheral resistance (peh-RIF-er-al)

[peri- around, -phera- boundary, -al relating to]

primary principle of circulation (PRY-mair-ee PRIN-sip-al of ser-kyoo-LAY-shun)

[prim- first, -ary relating to, princip- foundation, circulat- go around, -tion process]

pulse

[pulse beat]

pulse pressure (PRESH-ur)

[pulse beat]

pulse wave

[pulse beat]

P wave

[named for letter of Roman alphabet]

QRS complex (Q R S KOM-pleks)

[named for letters of Roman alphabet]

renin-angiotensin-aldosterone system (RAAS) (REE-nin-an-jee-oh-TEN-sin-al-DAH-stair-ohn SIS-tem)

[ren- kidney, -in substance, angio- vessel, -tens- pressure or stretch, -in substance, aldo- aldehyde, -stero- solid or steroid derivative, -one chemical, system organized whole]

residual volume (ree-ZID-yoo-al)

[residu- remainder, -al relating to]

sinoatrial (SA) node (sye-no-AY-tree-al)

[sin- hollow (sinus), -atri- entrance courtyard, -al relating to, nod- knot]

sphygmomanometer (sfig-moh-mah-NOM-eh-ter)

[sphygmo- pulse, -mano- thin, -meter measure]

stroke volume (SV)

subendocardial branch (sub-en-doh-KAR-dee-al)

[sub- under, -endo- within, -cardi- heart, -al relating to]

systole (SIS-toh-lee)

[systole contraction]

systolic blood pressure (sis-TOL-ik PRESH-ur)

[systole- contraction, -ic relating to]

T wave

[named for letter of Roman alphabet]

vasoconstriction (vay-soh-kon-STRIK-shun)

[vaso- vessel, -constrict- draw tight, -tion state]

vasodilation (vay-soh-dye-LAY-shun)

[vaso- vessel, -dilat- widen, -tion state]

vasomotor center (vay-so-MOH-tor)

[vaso- vessel, -motor move]

vasomotor mechanism (vay-so-MOH-tor MEK-ah-nih-zem)

[vaso- vessel, -motor move, mechan- machine, -ism state]

venous pump (VEE-nus pump)

[ven- vein, -ous relating to]

venous return (VEE-nus)

[ven- vein, -ous relating to]

BOBBY was in a hurry to finish the last job of the day. He had been called in to help complete and inspect the wiring in a museum that was due to open the next week. Bobby called to his coworker, Jerry, to confirm the current was off to the electrical box on which he was working. When he heard a positive response, he climbed the ladder and reached up to tighten a few loose screws. As he was tightening the screws with his right hand, he lost his balance and reached up with his left hand to catch hold of the ladder…but instead caught a live wire that sent a jolt of electricity through his body.

Jerry came running and knocked the ladder out from under Bobby so he would fall to the floor, breaking the electric arc. “Are you okay?” he asked Bobby, who appeared dazed, but was conscious. “I don’t feel so great,” he replied, smiling weakly. Then he collapsed. Jerry yelled at the other workers in the room to call 911, checked Bobby’s pulse, and started CPR. The foreman rushed in with an automated external defibrillator (AED) and attached the electrodes to Bobby’s chest. The AED’s mechanical voice said, “Press button when clear.”

As you read through this chapter, you’ll understand the electrical mechanism that operates your heart.

Now that you have read this chapter, see if you can answer these questions about the shock Bobby received in the Introductory Story.

When activated, the AED shocks the heart—the intended purpose being electrical stimulation of the cardiac muscle cells to elicit a response from the heart’s pacemaker that will cause the cells to contract in unison to effectively pump blood.

1.What bundle of cells in Bobby’s heart (and yours) is known as the pacemaker?

a.SV node

b.SA node

c.AV node

d.AV bundle

When the paramedics arrive, they rush Bobby to the hospital. “Let’s get an EKG!” the attending physician calls out.

2.What is an EKG?

a.Electrocardiogram

b.Electrocirculogram

c.Encephalocardiogram

d.Enhancercardiogram

3.Ventricular depolarization is shown as which part of the EKG?

a.V wave

b.P wave

c.T wave

d.QRS complex

To solve a case study, you may have to refer to the glossary or index, other chapters in this textbook, A&P Connect, Mechanisms of Disease, and other resources.

FUNCTION OF THE HEART AND BLOOD VESSELS

Our bodies are never at rest. In fact, a continuous supply of energy is required to maintain a relatively constant internal environment. This homeostatic maintenance of our body is due in large part to the continuous and controlled movement of blood throughout our circulatory system. Blood carries out most of its important transport functions in the thousands of miles of capillaries that comprise much of this system. As you might suspect, however, the body’s total blood volume is not evenly distributed. The regulation of blood pressure and blood flow must therefore change in response to cellular activity.

There are many control mechanisms that help to regulate and integrate the diverse functions and component parts of our cardiovascular system. This system must work to supply blood to specific body areas according to their immediate needs. These mechanisms ensure a relatively constant internal environment surrounding each body cell. In this chapter we will explore the control mechanisms that regulate the pumping action of the heart. We will also see how these mechanisms ensure the smooth and directed flow of blood throughout our circulatory system.

HEMODYNAMICS

Hemodynamics refers to the various mechanisms that influence the movement of blood. This is vital, of course, because different organs may need vastly different amounts of blood flow, depending on their metabolic activity. For example, working muscles need a far greater blood supply than do resting muscles. This is because tissues and organs (such as working muscles) with a greater metabolic rate obviously need more oxygen. And that oxygen is delivered by the RBCs of flowing blood in the capillaries. Because the amount of blood in our bodies is relatively constant, this means that the flow of blood to specific areas must be managed according to their activities. We will begin with a discussion of the physiology of the heart and then examine blood flow throughout the cardiovascular system.

A&P CONNECT

Whether blood flows straight through vessels or in a swirling, turbulent pattern has great clinical significance. For example, turbulent flow may signal a partially blocked artery and may promote the formation of dangerous blood clots. Learn more about this concept in Focus on Turbulent Blood Flow online at A&P Connect.

THE HEART AS A PUMP

Recall from Chapter 17 that the left side of the heart services the systemic circulatory route, which supplies blood flow to the entire body, except to the lungs. The right side of the heart services the pulmonary circulatory route, which supplies blood flow to and from the lungs. Both routes require coordination so that they function as a single pumping structure. To do this, the impulses (action potentials) that trigger contraction must be coordinated. The heart must have a system to generate rhythmic impulses. It must then distribute these impulses to the different regions of the myocardium. This distribution is accomplished by the impulse-conducting pathway. Four structures make up the core of the conduction system of the heart:

1.Sinoatrial (SA) node

2.Atrioventricular (AV) node

3.AV bundle (bundle of His)

4.Subendocardial branches (Purkinje fibers)

You can see these structures represented in Figure 18-1. Please refer to this figure as you read through the following discussion.

The structures that make up the heart’s conduction system are composed of cells that differ in function from those of ordinary cardiac muscle: The heart conduction cells cannot contract strongly. Instead, they permit the generation or rapid conduction of an action potential throughout the myocardium.

Normally, the cardiac impulses that control heart contraction begin in the sinoatrial (SA) node. This node, also called the “pacemaker,” is located just below the atrial epicardium at its junction with the superior vena cava (Figure 18-1, A). The pacemaker cells in the SA node have an intrinsic rhythm. This means that they do not require nervous input from the brain or spinal cord. They themselves initiate impulses at regular intervals. In fact, if you remove pacemaker cells and put them in a nutrient solution, they will continue to beat! They do not require nervous or hormonal stimulation to contract.

FIGURE 18-1 Conduction system of the heart. Specialized cardiac muscle cells (boldface type) in the wall of the heart rapidly initiate or conduct an electrical impulse throughout the myocardium. Both the sketch of the conduction system (A) and the flowchart (B) show the origin and path of conduction. The signal is initiated by the SA node (pacemaker) and spreads directly to the rest of the right atrial myocardium. From there, it travels to the left atrial myocardium by way of a bundle of interatrial conducting fibers, and then to the AV node by way of three internodal bundles. The AV node then initiates a signal that is conducted through the ventricular myocardium by way of the AV bundle (of His) and subendocardial branches (Purkinje fibers).

However, in a living heart, there are nervous and hormonal components that influence the cells of the pacemaker.

Here’s an overview of how the heart’s conduction system works (Figure 18-1, B). Each impulse generated at the sinoatrial (SA) node travels swiftly throughout the muscle fibers of both atria. (An interatrial bundle of conducting fibers provides rapid conduction to the left atrium.) Thus, the atria begin to contract. The action potential next enters the atrioventricular (AV) node via three internodal bundles. These bundles are also composed of conducting fibers. Here the conduction of the impulse slows considerably. This allows the atria to contract completely before the conduction reaches the ventricles below.

After passing slowly through the AV node, the conduction velocity increases again as the impulse is relayed through the atrioventricular (AV) bundle (also called the bundle of His). At this point, the right and left bundle branches and the subendocardial branches (also called the Purkinje fibers) in which they terminate conduct the impulses throughout the muscle of both ventricles. This impulse stimulates the ventricular muscle fibers to contract almost simultaneously.

Thus the SA node initiates each heartbeat and sets the basic pace—it is the heart’s own natural pacemaker. Under the influence of autonomic and endocrine controls, the SA node will normally “fire” at an intrinsic rhythmical rate of 70 to 75 beats per minute under resting conditions. However, if for any reason the SA node loses its ability to generate an impulse, pacemaker activity will shift to another excitable component of the conduction system. These might include the AV node or the subendocardial branches. Pacemakers other than the SA node are abnormal. They are called ectopic pacemakers. Unfortunately, such ancillary pacemakers usually set a much slower rhythm—only 40 to 60 beats per minute. If the heart’s own pacemaker fails to maintain a healthy heart rhythm, an artificial pacemaker can be implanted to restore normal function.

A&P CONNECT

Artificial pacemakers can help keep individuals with damaged hearts alive for many years. Check out Artificial Cardiac Pacemakers online at A&P Connect to see how these devices work and how they are implanted.

Electrocardiogram (ECG)

Electrocardiography

Impulse conduction in the heart generates tiny electrical currents that spread through surrounding tissues to the surface of the body. This fact has great clinical importance because these currents can be measured with an electrocardiograph. An electrocardiogram (ECG) is produced by attaching electrodes of a recording voltmeter (the electrocardiograph) to the chest and/or limbs of the subject (Figure 18-2, A).

FIGURE 18-2 Electrocardiogram. A, A nurse monitors a patient’s ECG as he exercises on a treadmill. B, Idealized ECG deflections represent depolarization and repolarization of cardiac muscle tissue. C, Principal ECG intervals between P, QRS, and T waves. Note that the P-R interval is measured from the start of the P wave to the start of the Q wave.

FIGURE 18-3 The basic theory of electrocardiography.

FIGURE 18-4 Events represented by the electrocardiogram (ECG). It is impossible to illustrate the invisible, dynamic events of heart conduction in a few cartoon panels or “snapshots.” However, the sketches here give you an idea of what is happening in the heart as an ECG is recorded. Note that depolarization triggers contraction in the affected muscle tissue. Thus cardiac muscle contraction occurs after depolarization begins.

(The abbreviation for an electrocardiogram is ECG when it is written and EKG when it is spoken.) The ECG is not a record of the heart’s contractions but of the electrical events that precede the contractions.

You can see changes in voltage (which represent changes in the heart’s electrical activity) as deflections of the line in a recording voltmeter (Figure 18-3). We’ve simplified the situation somewhat by showing only a single cardiac muscle fiber with the two electrodes of a recording voltmeter nearby.

Before the action potential reaches either electrode, there is no difference in charge between them. Thus, no change in voltage is recorded on the voltmeter graph (Figure 18-3, step 1).

As an action potential reaches the first electrode, the external surface of the sarcolemma becomes relatively negative. This results in an upward deflection of the pen of the recording chart (Figure 18-3, step 2). (Note that the voltmeter records the difference in charge between the two electrodes.) When the action potential also reaches the second electrode, the pen returns to the zero baseline. This happens because there is no difference in charge once again between the two electrodes (Figure 18-3, step 3).

As the end of the action potential passes the first electrode, the sarcolemma is again relatively positive on its outer surface. This causes the pen to again deflect away from the baseline. This time, however, because the direction of the negative and positive electrodes is reversed, the pen deflects downward (Figure 18-3, step 4). After the end of the action potential also passes the second electrode, the pen again returns to the zero baseline (Figure 18-3, step 5).

In short, when ECG electrodes are set up this way, depolarization of the cardiac muscle causes a deflection upward; repolarization causes a deflection downward. However, depending on the location of electrodes relative to heart muscle, the direction of ECG waves can vary. It is this activity that is detected in an electrocardiogram. Many ECG setups in use today show these voltage fluctuations in real time on a video monitor and at the same time records them in a computer file and on a paper chart (like the one represented in Figure 18-3).

ECG Waves

We will limit our discussion of electrocardiography to normal ECG deflection waves and the ECG intervals between them. As we do so, please refer to Figure 18-2 and the sequence of events presented in Figure 18-4.

As you can see in Figures 18-2 and 18-4, the normal ECG is composed of deflection waves called the P wave, QRS complex, and T wave. (The letters do not represent any words; they were simply chosen as an arbitrary sequence of letters!)

The P wave represents depolarization of the atria. It measures the deflection caused by the passage of an electrical impulse from the SA node through the musculature of the atria.

The QRS complex represents the depolarization of the ventricles. This is a multi-step process. First there is the depolarization of the interventricular septum. This is followed by the spread of depolarization by the subendocardial branches (Purkinje fibers) through the lateral ventricular walls. All three deflections, then—Q, R, and S together—represent the entire process of depolarization of the ventricles.

There is a slight catch. At the same time that the ventricles are depolarizing, the atria are repolarizing. You might expect to see some indication of this in the ECG tracing. However, the massive ventricular depolarization that is occurring at the same time literally “drowns out” the relatively small voltage fluctuation produced by atrial repolarization. For this reason, the QRS complex represents the net deflection due to both ventricular depolarization and atrial repolarization.

The T wave reflects repolarization of the ventricles. Depending on exactly where the electrodes are placed relative to the direction of electrical activity in the ventricular myocardium, this repolarization wave may deflect the ECG trace in the same direction as in depolarization.

ECG Intervals

The principal ECG intervals between P, QRS, and T waves are illustrated for you in Figure 18-2, C. Measurement of these intervals can provide important information concerning the rate of conduction of an action potential through the heart.

1. What is meant by hemodynamics?

2. Briefly outline the conduction system of the heart.

3. How does an electrocardiograph work?

4. What are the major deflections in an ECG?

5. What conduction event does each type of ECG wave represent?

Cardiac Cycle

The cardiac cycle describes a complete heartbeat or a single pumping cycle. It consists of contraction (systole) and relaxation (diastole) of both atria and both ventricles. First, the two atria contract simultaneously. Then, as the atria relax, the two ventricles contract and relax. As a result, all the chambers of the heart do not contract as a single unit. This alternation of contraction and relaxation imparts a pumping rhythm to the heart.

During the following discussion, please refer often to Figure 18-5, which shows the major phases of the cardiac cycle.

Atrial Systole

The contracting myocardium of the atria forces the blood into the ventricles below. The atrioventricular (cuspid) valves are opened during this phase to allow for the passage of blood into the relaxed ventricles. The semilunar valves are closed, preventing blood return from the aorta or the pulmonary trunk. This part of the cycle is represented by the P wave on an ECG. Passage of the electrical wave of depolarization is then followed almost immediately by actual contraction of the atrial musculature.

Ventricular Contraction

During the brief period of ventricular contraction (between the start of ventricular systole and the opening of the semilunar valves), the volume of blood in the ventricles remains constant (isovolumetric). However, the pressure inside the ventricles increases rapidly. The ventricular systole is marked by the R wave on the ECG. At this time, the first audible heart sound (often described as a “lubb”) is produced.

Ejection

The semilunar valves open and blood is ejected under great force from the ventricles. At this point, the pressure in the ventricles exceeds the pressure in the pulmonary artery and aorta, and blood is pushed into these vessels. This rapid ejection is characterized by a marked increase in ventricular and aortic pressure. The T wave of the ECG appears during the later, long phase of reduced ejection. You might think of this as the tail end of the contraction. However, a considerable quantity of blood, called the residual volume, remains in the ventricles even at the end of the ejection period. In heart failure, the residual volume remaining in the ventricles may greatly exceed the volume ejected into the aorta and pulmonary trunk.

Ventricular Relaxation

Diastole—the relaxation of the ventricles—begins with this period between closing of the semilunar valves and the opening of the atrioventricular valves. At the end of ventricular contraction, the semilunar valves close so that blood cannot re-enter back into the ventricles from the great vessels. The second heart sound (described as a “dupp”) is now heard.

The atrioventricular valves do not open until the pressure in the atrial chambers exceeds the pressure in the relaxed ventricles. The result is a dramatic fall in intraventricular pressure—but no change in blood volume. This is an isovolumetric phase—both sets of valves are closed.

Passive Ventricular Filling

The continuing return of venous blood from the venae cavae and the pulmonary veins increases pressure within both atria until the atrioventricular valves are forced open. When this happens, blood rushes into the relaxed ventricles. This rapid influx of blood lasts only about 0.1 second but results in a

FIGURE 18-5 The cardiac cycle. The five steps of the heart’s pumping cycle described in the text are shown as a series of changes in the heart wall and valves. The term isovolumetric means that the volume remains constant.

dramatic increase in the volume of blood in the ventricle. The abrupt inflow of blood that occurs immediately after opening of the AV valves is followed by a slow and continuous flow of venous blood into the atria. This blood then flows through the open AV valves and into the ventricles, slowly building up the blood pressure and volume within the ventricles.

Heart Sounds

The first “lubb” or systolic sound is caused largely by the contraction of the ventricles and by the closing atrioventricular valves. It is longer and lower than the second or diastolic sound, which is short and sharp. Vibrations of the closing semilunar valves cause this second “dupp” sound.

Heart sounds have clinical significance and can provide information about the valves. Any variation from normal “lubb-dupp” sounds may suggest imperfect valve function. A heart murmur is one commonly heard type of abnormal heart sound. Sometimes it is described as a “swishing” sound. This may indicate an incomplete closing of the valves or stenosis (constriction or narrowing) of the valves.

6. Briefly outline the steps of the cardiac cycle.

7. When are heart sounds of medical importance?

PRIMARY PRINCIPLE OF CIRCULATION

In order for blood to flow within the circulatory system, there must be a gradient from high pressure to low pressure (Figure 18-6). This is sometimes called the primary principle of circulation. For example, blood enters an arteriole at 85 mm Hg and leaves at 35 mm Hg. The blood thus moves down a pressure gradient (from 85 mm Hg to 35 mm Hg) as it flows through the arteriole. The pressure difference drives the flow of blood.

ARTERIAL BLOOD PRESSURE

High pressure in the arteries must be maintained to keep blood flowing through the circulatory system. The volume of blood within the arteries largely determines arterial blood pressure. Thus, an increase in arterial blood volume tends to increase arterial pressure. Likewise, a decrease in arterial volume tends to decrease arterial pressure. However, many factors determine arterial pressure through their influence on arterial volume. Two of the most important, cardiac output and peripheral resistance, are directly proportional to blood volume, as we will see below.

FIGURE 18-6 The primary principle of circulation. Fluid always travels from an area of high pressure to an area of low pressure. Water flows from an area of high pressure in the tank (100 mm Hg) toward the area of low pressure above the bucket (0 mm Hg). Blood tends to move from an area of high average pressure at the beginning of the aorta (100 mm Hg) toward the area of lowest pressure at the end of the venae cavae (0 mm Hg). Blood flow between any two points in the circulatory system can always be predicted by the pressure gradient.

Cardiac Output

Cardiac output (CO) is the amount of blood that flows out of a ventricle per unit of time. For example, the resting cardiac output from the left ventricle into the systemic arteries is about 5,000 ml/min. The cardiac output influences the flow rate to the various organs of the body. For the sake of our discussion, we will focus on the cardiac output from the left ventricle into the systemic loop.

Cardiac output is determined by the volume of blood pumped out of a ventricle by each beat (stroke volume or SV) and by heart rate (HR). Because contraction of the heart is called systole, sometimes the volume of blood pumped by one contraction is called the systolic discharge. Stroke volume, or volume pumped per heartbeat, is one of two major factors that determine cardiac output. CO can be determined by the following equation:

SV

(

volume

/

beat

)

×

HR

(

beats

/

min

)

=

CO

(

volume

/

min

)

Thus the greater the stroke volume, the greater the CO (but only if the heart rate remains constant). Anything that changes the rate of the heartbeat or its stroke volume tends to change CO. This means that anything that makes the heart beat faster or stronger (increases its stroke volume) tends to increase CO and therefore arterial blood volume and pressure. Conversely, anything that causes the heart to beat more slowly or more weakly (decreases its stroke volume) tends to decrease CO, arterial volume, and blood pressure.

The following sections, and Figure 18-7, summarize a few of the major factors that affect cardiac output.

Factors that Affect Stroke Volume

Mechanical, neural, and chemical factors regulate the strength of the heartbeat and therefore its stroke volume.

One mechanical factor that helps determine stroke volume is the length of the myocardial fibers at the beginning of ventricular contraction. According to the Frank-Starling mechanism, the longer or more stretched the heart fibers are at the beginning of contraction (up to a critical limit), the stronger is their contraction. The more blood returned to the heart per minute, the more stretched will be their fibers. This will lead to stronger contractions and a larger volume of blood ejected with each contraction.

However, if too much blood stretches the heart beyond a certain critical limit, the myocardial muscle seems to lose its elasticity. As a result the heart contracts less vigorously.

We can now see that the heart pumps out what it receives. That is, within certain limits, the strength of myocardial contraction matches the pumping load. This is contrary to most mechanical pumps that do not adjust themselves to their input with every stroke. In the case of a human heart, under ordinary conditions, it automatically adjusts output (stroke volume) to input (venous return to the heart).

Other factors that influence stroke volume are neural and endocrine chemical factors. Norepinephrine (released by sympathetic fibers in the cardiac nerve) and epinephrine (released into the blood by the adrenal medulla) can both increase the strength of contraction, or contractility, of the myocardium. This increased contractility of the heart muscle forces more blood volume out of the heart per cardiac stroke, thus increasing the stroke volume.

Factors that Affect Heart Rate

Although the sinoatrial node normally initiates each heartbeat, the heart rate it sets can be altered. In fact, various factors can and do change the rate of the heartbeat. One major modifier is the ratio of sympathetic and parasympathetic impulses conducted to the node per minute. This is because autonomic control of heart rate is the result of opposing influences between the parasympathetic (chiefly vagus) and sympathetic (cardiac nerve) stimulation. The parasympathetic stimulation is inhibitory—mediated by acetylcholine released by the vagus nerve. The sympathetic stimulation is stimulatory—mediated by the release of norepinephrine at the distal end of the cardiac nerve.

Cardiac Pressoreflexes

Receptors sensitive to changes in pressure (baroreceptors) are located in two places near the heart. The aortic baroreceptors and the carotid baroreceptors send afferent nerve fibers to cardiac control centers in the medulla oblongata. These stretch

FIGURE 18-7 Factors affecting cardiac output.

receptors, located in the aorta and carotid sinus, respectively, are vitally important to controlling heart rate. Baroreceptors operate with integrators in the cardiac control centers in negative feedback loops called pressoreflexes. These oppose changes in pressure by adjusting heart rate.

Other Reflexes that Influence Heart Rate

Reflexes involving important factors such as emotions, exercise, hormones, blood temperature, pain, and stimulation of various exteroceptors also influence heart rate.

Anatomy homework help

CRITICAL REVIEW EVALUATION 2022

Content & Point Value Totals

Exc.

S

U

0

Points


INTRODUCTORY PARAGRAPH

CATCH the reader’s attention and/or introduce the topic of the critical review. IDENTIFY the play (title, playwright) and where the production was presented. PROVIDE some background about this play’s origin, playwright, and the playwright’s intended objective(s) for writing this play. COMPOSE a thesis statement that indicates that this review is commentary on the director’s choices for the acting and the design, as well as the work of the designers and actors. [20 pts.]


FIRST IMPRESSIONS
HOW does the play begin? Does it provide any backstory, or set the atmosphere, or start immediately with the action of the storyline? DESCRIBE the design elements in the first scene: scenic, lighting, sound, costumes, makeup. Which design choices stand out to you—positively or negatively— and why? [20 pts.]


DESIGN
HOW realistic or theatrical are the designs? How do they impact your experience of the production? IDENTIFY, throughout the production, identify the scenic elements, costume elements, makeup, and use of lighting and sound that are most effective and/or least effective. EXPLAIN why they fit your decisions about their values. As the director has the final say on design, comment on the effectiveness (positive or negative) of each element you have highlighted; you may compliment his/her/their choices and/or question why a particular choice was made. [20 pts.]


ACTING
DESCRIBE the style of acting (realistic or stylistic). Does it fit with the design style? How does this style impact your experience of the production? As the director has the final say on the acting, comment on the effectiveness of what his/her/their choices and/or question why a particular choice was made. [20 pts.]


DIRECTING
— Considering the guidance of the director, which elements (acting or visual design) indicate the director’s choice of focus? [10 pts.]


CONCLUSION
– Give an overall statement about the elements (directing, acting, design) and how they impacted the audience experience of the production. [10 pts.]

Theatre terminology – incorrect use of terms = minus points

Writing quality – errors in spelling, lack of proofreading, fragments or run-ons, incorrect punctuation = minus points

Paper Grade

[Total of 100 points possible]


NOTES FROM THE INSTRUCTOR:

Anatomy homework help

CHAPTER 18 Physiology of the Cardiovascular System

STUDENT LEARNING OBJECTIVES

At the completion of this chapter, you should be able to do the following:

1.List the basic components of the cardiovascular system.

2.Describe the structures of the heart and how they serve to pump blood.

3.Discuss the deflection waves of a normal ECG and explain their significance.

4.Outline the basic steps of the cardiac cycle.

5.Discuss the primary principle of circulation and the significance of high arterial blood pressure.

6.Describe factors that affect stroke volume and heart rate.

7.Discuss the significance of peripheral resistance in the cardiovascular system.

8.Discuss the significance of the vasomotor control mechanism.

9.Discuss how the respiratory pump and skeletal muscle pump work to assist the venous return of blood to the heart.

10.Outline the hormonal mechanisms that regulate blood volume.

11.Discuss the significance of the pulse mechanism.

12.List several major pulse points in the body.

LANGUAGE OF SCIENCE AND MEDICINE

Before reading the chapter, say each of these terms out loud. This will help you avoid stumbling over them as you read.

ADH mechanism (A-D-H MEK-ah-nih-zem)

[ADH antidiuretic hormone, mechan- machine, -ism state]

ANH mechanism (A-N-H MEK-ah-nih-zem)

[ANH atrial natriuretic hormone, mechan- machine, -ism state]

atrioventricular (AV) bundle (ay-tree-oh-ven-TRIK-yoo-lar BUN-del)

[atrio- entrance courtyard, -ventr- belly, -icul- little, -ar relating to]

atrioventricular (AV) node (ay-tree-oh-ven-TRIK-yoo-lar)

[atrio- entrance courtyard, -ventr- belly, -icul- little, -ar relating to, nod- knot]

baroreceptor (bar-oh-ree-SEP-tor)

[baro- pressure, -recept- receive, -or agent]

cardiac cycle (KAR-dee-ak SYE-kul)

[cardi- heart, -ac relating to, cycle circle]

cardiac output (CO) (KAR-dee-ak)

[cardi- heart, -ac relating to]

conduction system of the heart (kon-DUK-shen SIS-tem)

[conduct- lead, -tion process, system organized whole]

contractility (kon-trak-TIL-ih-tee)

[con- together, -tract- drag or draw, -il- of or like, -ity quality of]

diastole (dye-ASS-toh-lee)

[dia- through, -stole contraction]

diastolic blood pressure (dye-ah-STOL-ik PRESH-ur)

[dia- apart or through, -stol- contraction, -ic relating to]

ectopic pacemaker (ek-TOP-ik PAYS-may-ker)

[ec- out of, -top- place, -ic relating to]

electrocardiogram (ECG or EKG) (eh-lek-troh-KAR-dee-oh-gram)

[electro- electricity, -cardio- heart, -gram drawing]

heart murmur

[murmur hum]

heart rate (HR)

hemodynamics (hee-moh-dye-NAM-iks)

[hemo- blood, -dynami- force, -ic relating to]

peripheral resistance (peh-RIF-er-al)

[peri- around, -phera- boundary, -al relating to]

primary principle of circulation (PRY-mair-ee PRIN-sip-al of ser-kyoo-LAY-shun)

[prim- first, -ary relating to, princip- foundation, circulat- go around, -tion process]

pulse

[pulse beat]

pulse pressure (PRESH-ur)

[pulse beat]

pulse wave

[pulse beat]

P wave

[named for letter of Roman alphabet]

QRS complex (Q R S KOM-pleks)

[named for letters of Roman alphabet]

renin-angiotensin-aldosterone system (RAAS) (REE-nin-an-jee-oh-TEN-sin-al-DAH-stair-ohn SIS-tem)

[ren- kidney, -in substance, angio- vessel, -tens- pressure or stretch, -in substance, aldo- aldehyde, -stero- solid or steroid derivative, -one chemical, system organized whole]

residual volume (ree-ZID-yoo-al)

[residu- remainder, -al relating to]

sinoatrial (SA) node (sye-no-AY-tree-al)

[sin- hollow (sinus), -atri- entrance courtyard, -al relating to, nod- knot]

sphygmomanometer (sfig-moh-mah-NOM-eh-ter)

[sphygmo- pulse, -mano- thin, -meter measure]

stroke volume (SV)

subendocardial branch (sub-en-doh-KAR-dee-al)

[sub- under, -endo- within, -cardi- heart, -al relating to]

systole (SIS-toh-lee)

[systole contraction]

systolic blood pressure (sis-TOL-ik PRESH-ur)

[systole- contraction, -ic relating to]

T wave

[named for letter of Roman alphabet]

vasoconstriction (vay-soh-kon-STRIK-shun)

[vaso- vessel, -constrict- draw tight, -tion state]

vasodilation (vay-soh-dye-LAY-shun)

[vaso- vessel, -dilat- widen, -tion state]

vasomotor center (vay-so-MOH-tor)

[vaso- vessel, -motor move]

vasomotor mechanism (vay-so-MOH-tor MEK-ah-nih-zem)

[vaso- vessel, -motor move, mechan- machine, -ism state]

venous pump (VEE-nus pump)

[ven- vein, -ous relating to]

venous return (VEE-nus)

[ven- vein, -ous relating to]

BOBBY was in a hurry to finish the last job of the day. He had been called in to help complete and inspect the wiring in a museum that was due to open the next week. Bobby called to his coworker, Jerry, to confirm the current was off to the electrical box on which he was working. When he heard a positive response, he climbed the ladder and reached up to tighten a few loose screws. As he was tightening the screws with his right hand, he lost his balance and reached up with his left hand to catch hold of the ladder…but instead caught a live wire that sent a jolt of electricity through his body.

Jerry came running and knocked the ladder out from under Bobby so he would fall to the floor, breaking the electric arc. “Are you okay?” he asked Bobby, who appeared dazed, but was conscious. “I don’t feel so great,” he replied, smiling weakly. Then he collapsed. Jerry yelled at the other workers in the room to call 911, checked Bobby’s pulse, and started CPR. The foreman rushed in with an automated external defibrillator (AED) and attached the electrodes to Bobby’s chest. The AED’s mechanical voice said, “Press button when clear.”

As you read through this chapter, you’ll understand the electrical mechanism that operates your heart.

Now that you have read this chapter, see if you can answer these questions about the shock Bobby received in the Introductory Story.

When activated, the AED shocks the heart—the intended purpose being electrical stimulation of the cardiac muscle cells to elicit a response from the heart’s pacemaker that will cause the cells to contract in unison to effectively pump blood.

1.What bundle of cells in Bobby’s heart (and yours) is known as the pacemaker?

a.SV node

b.SA node

c.AV node

d.AV bundle

When the paramedics arrive, they rush Bobby to the hospital. “Let’s get an EKG!” the attending physician calls out.

2.What is an EKG?

a.Electrocardiogram

b.Electrocirculogram

c.Encephalocardiogram

d.Enhancercardiogram

3.Ventricular depolarization is shown as which part of the EKG?

a.V wave

b.P wave

c.T wave

d.QRS complex

To solve a case study, you may have to refer to the glossary or index, other chapters in this textbook, A&P Connect, Mechanisms of Disease, and other resources.

FUNCTION OF THE HEART AND BLOOD VESSELS

Our bodies are never at rest. In fact, a continuous supply of energy is required to maintain a relatively constant internal environment. This homeostatic maintenance of our body is due in large part to the continuous and controlled movement of blood throughout our circulatory system. Blood carries out most of its important transport functions in the thousands of miles of capillaries that comprise much of this system. As you might suspect, however, the body’s total blood volume is not evenly distributed. The regulation of blood pressure and blood flow must therefore change in response to cellular activity.

There are many control mechanisms that help to regulate and integrate the diverse functions and component parts of our cardiovascular system. This system must work to supply blood to specific body areas according to their immediate needs. These mechanisms ensure a relatively constant internal environment surrounding each body cell. In this chapter we will explore the control mechanisms that regulate the pumping action of the heart. We will also see how these mechanisms ensure the smooth and directed flow of blood throughout our circulatory system.

HEMODYNAMICS

Hemodynamics refers to the various mechanisms that influence the movement of blood. This is vital, of course, because different organs may need vastly different amounts of blood flow, depending on their metabolic activity. For example, working muscles need a far greater blood supply than do resting muscles. This is because tissues and organs (such as working muscles) with a greater metabolic rate obviously need more oxygen. And that oxygen is delivered by the RBCs of flowing blood in the capillaries. Because the amount of blood in our bodies is relatively constant, this means that the flow of blood to specific areas must be managed according to their activities. We will begin with a discussion of the physiology of the heart and then examine blood flow throughout the cardiovascular system.

A&P CONNECT

Whether blood flows straight through vessels or in a swirling, turbulent pattern has great clinical significance. For example, turbulent flow may signal a partially blocked artery and may promote the formation of dangerous blood clots. Learn more about this concept in Focus on Turbulent Blood Flow online at A&P Connect.

THE HEART AS A PUMP

Recall from Chapter 17 that the left side of the heart services the systemic circulatory route, which supplies blood flow to the entire body, except to the lungs. The right side of the heart services the pulmonary circulatory route, which supplies blood flow to and from the lungs. Both routes require coordination so that they function as a single pumping structure. To do this, the impulses (action potentials) that trigger contraction must be coordinated. The heart must have a system to generate rhythmic impulses. It must then distribute these impulses to the different regions of the myocardium. This distribution is accomplished by the impulse-conducting pathway. Four structures make up the core of the conduction system of the heart:

1.Sinoatrial (SA) node

2.Atrioventricular (AV) node

3.AV bundle (bundle of His)

4.Subendocardial branches (Purkinje fibers)

You can see these structures represented in Figure 18-1. Please refer to this figure as you read through the following discussion.

The structures that make up the heart’s conduction system are composed of cells that differ in function from those of ordinary cardiac muscle: The heart conduction cells cannot contract strongly. Instead, they permit the generation or rapid conduction of an action potential throughout the myocardium.

Normally, the cardiac impulses that control heart contraction begin in the sinoatrial (SA) node. This node, also called the “pacemaker,” is located just below the atrial epicardium at its junction with the superior vena cava (Figure 18-1, A). The pacemaker cells in the SA node have an intrinsic rhythm. This means that they do not require nervous input from the brain or spinal cord. They themselves initiate impulses at regular intervals. In fact, if you remove pacemaker cells and put them in a nutrient solution, they will continue to beat! They do not require nervous or hormonal stimulation to contract.

FIGURE 18-1 Conduction system of the heart. Specialized cardiac muscle cells (boldface type) in the wall of the heart rapidly initiate or conduct an electrical impulse throughout the myocardium. Both the sketch of the conduction system (A) and the flowchart (B) show the origin and path of conduction. The signal is initiated by the SA node (pacemaker) and spreads directly to the rest of the right atrial myocardium. From there, it travels to the left atrial myocardium by way of a bundle of interatrial conducting fibers, and then to the AV node by way of three internodal bundles. The AV node then initiates a signal that is conducted through the ventricular myocardium by way of the AV bundle (of His) and subendocardial branches (Purkinje fibers).

However, in a living heart, there are nervous and hormonal components that influence the cells of the pacemaker.

Here’s an overview of how the heart’s conduction system works (Figure 18-1, B). Each impulse generated at the sinoatrial (SA) node travels swiftly throughout the muscle fibers of both atria. (An interatrial bundle of conducting fibers provides rapid conduction to the left atrium.) Thus, the atria begin to contract. The action potential next enters the atrioventricular (AV) node via three internodal bundles. These bundles are also composed of conducting fibers. Here the conduction of the impulse slows considerably. This allows the atria to contract completely before the conduction reaches the ventricles below.

After passing slowly through the AV node, the conduction velocity increases again as the impulse is relayed through the atrioventricular (AV) bundle (also called the bundle of His). At this point, the right and left bundle branches and the subendocardial branches (also called the Purkinje fibers) in which they terminate conduct the impulses throughout the muscle of both ventricles. This impulse stimulates the ventricular muscle fibers to contract almost simultaneously.

Thus the SA node initiates each heartbeat and sets the basic pace—it is the heart’s own natural pacemaker. Under the influence of autonomic and endocrine controls, the SA node will normally “fire” at an intrinsic rhythmical rate of 70 to 75 beats per minute under resting conditions. However, if for any reason the SA node loses its ability to generate an impulse, pacemaker activity will shift to another excitable component of the conduction system. These might include the AV node or the subendocardial branches. Pacemakers other than the SA node are abnormal. They are called ectopic pacemakers. Unfortunately, such ancillary pacemakers usually set a much slower rhythm—only 40 to 60 beats per minute. If the heart’s own pacemaker fails to maintain a healthy heart rhythm, an artificial pacemaker can be implanted to restore normal function.

A&P CONNECT

Artificial pacemakers can help keep individuals with damaged hearts alive for many years. Check out Artificial Cardiac Pacemakers online at A&P Connect to see how these devices work and how they are implanted.

Electrocardiogram (ECG)

Electrocardiography

Impulse conduction in the heart generates tiny electrical currents that spread through surrounding tissues to the surface of the body. This fact has great clinical importance because these currents can be measured with an electrocardiograph. An electrocardiogram (ECG) is produced by attaching electrodes of a recording voltmeter (the electrocardiograph) to the chest and/or limbs of the subject (Figure 18-2, A).

FIGURE 18-2 Electrocardiogram. A, A nurse monitors a patient’s ECG as he exercises on a treadmill. B, Idealized ECG deflections represent depolarization and repolarization of cardiac muscle tissue. C, Principal ECG intervals between P, QRS, and T waves. Note that the P-R interval is measured from the start of the P wave to the start of the Q wave.

FIGURE 18-3 The basic theory of electrocardiography.

FIGURE 18-4 Events represented by the electrocardiogram (ECG). It is impossible to illustrate the invisible, dynamic events of heart conduction in a few cartoon panels or “snapshots.” However, the sketches here give you an idea of what is happening in the heart as an ECG is recorded. Note that depolarization triggers contraction in the affected muscle tissue. Thus cardiac muscle contraction occurs after depolarization begins.

(The abbreviation for an electrocardiogram is ECG when it is written and EKG when it is spoken.) The ECG is not a record of the heart’s contractions but of the electrical events that precede the contractions.

You can see changes in voltage (which represent changes in the heart’s electrical activity) as deflections of the line in a recording voltmeter (Figure 18-3). We’ve simplified the situation somewhat by showing only a single cardiac muscle fiber with the two electrodes of a recording voltmeter nearby.

Before the action potential reaches either electrode, there is no difference in charge between them. Thus, no change in voltage is recorded on the voltmeter graph (Figure 18-3, step 1).

As an action potential reaches the first electrode, the external surface of the sarcolemma becomes relatively negative. This results in an upward deflection of the pen of the recording chart (Figure 18-3, step 2). (Note that the voltmeter records the difference in charge between the two electrodes.) When the action potential also reaches the second electrode, the pen returns to the zero baseline. This happens because there is no difference in charge once again between the two electrodes (Figure 18-3, step 3).

As the end of the action potential passes the first electrode, the sarcolemma is again relatively positive on its outer surface. This causes the pen to again deflect away from the baseline. This time, however, because the direction of the negative and positive electrodes is reversed, the pen deflects downward (Figure 18-3, step 4). After the end of the action potential also passes the second electrode, the pen again returns to the zero baseline (Figure 18-3, step 5).

In short, when ECG electrodes are set up this way, depolarization of the cardiac muscle causes a deflection upward; repolarization causes a deflection downward. However, depending on the location of electrodes relative to heart muscle, the direction of ECG waves can vary. It is this activity that is detected in an electrocardiogram. Many ECG setups in use today show these voltage fluctuations in real time on a video monitor and at the same time records them in a computer file and on a paper chart (like the one represented in Figure 18-3).

ECG Waves

We will limit our discussion of electrocardiography to normal ECG deflection waves and the ECG intervals between them. As we do so, please refer to Figure 18-2 and the sequence of events presented in Figure 18-4.

As you can see in Figures 18-2 and 18-4, the normal ECG is composed of deflection waves called the P wave, QRS complex, and T wave. (The letters do not represent any words; they were simply chosen as an arbitrary sequence of letters!)

The P wave represents depolarization of the atria. It measures the deflection caused by the passage of an electrical impulse from the SA node through the musculature of the atria.

The QRS complex represents the depolarization of the ventricles. This is a multi-step process. First there is the depolarization of the interventricular septum. This is followed by the spread of depolarization by the subendocardial branches (Purkinje fibers) through the lateral ventricular walls. All three deflections, then—Q, R, and S together—represent the entire process of depolarization of the ventricles.

There is a slight catch. At the same time that the ventricles are depolarizing, the atria are repolarizing. You might expect to see some indication of this in the ECG tracing. However, the massive ventricular depolarization that is occurring at the same time literally “drowns out” the relatively small voltage fluctuation produced by atrial repolarization. For this reason, the QRS complex represents the net deflection due to both ventricular depolarization and atrial repolarization.

The T wave reflects repolarization of the ventricles. Depending on exactly where the electrodes are placed relative to the direction of electrical activity in the ventricular myocardium, this repolarization wave may deflect the ECG trace in the same direction as in depolarization.

ECG Intervals

The principal ECG intervals between P, QRS, and T waves are illustrated for you in Figure 18-2, C. Measurement of these intervals can provide important information concerning the rate of conduction of an action potential through the heart.

1. What is meant by hemodynamics?

2. Briefly outline the conduction system of the heart.

3. How does an electrocardiograph work?

4. What are the major deflections in an ECG?

5. What conduction event does each type of ECG wave represent?

Cardiac Cycle

The cardiac cycle describes a complete heartbeat or a single pumping cycle. It consists of contraction (systole) and relaxation (diastole) of both atria and both ventricles. First, the two atria contract simultaneously. Then, as the atria relax, the two ventricles contract and relax. As a result, all the chambers of the heart do not contract as a single unit. This alternation of contraction and relaxation imparts a pumping rhythm to the heart.

During the following discussion, please refer often to Figure 18-5, which shows the major phases of the cardiac cycle.

Atrial Systole

The contracting myocardium of the atria forces the blood into the ventricles below. The atrioventricular (cuspid) valves are opened during this phase to allow for the passage of blood into the relaxed ventricles. The semilunar valves are closed, preventing blood return from the aorta or the pulmonary trunk. This part of the cycle is represented by the P wave on an ECG. Passage of the electrical wave of depolarization is then followed almost immediately by actual contraction of the atrial musculature.

Ventricular Contraction

During the brief period of ventricular contraction (between the start of ventricular systole and the opening of the semilunar valves), the volume of blood in the ventricles remains constant (isovolumetric). However, the pressure inside the ventricles increases rapidly. The ventricular systole is marked by the R wave on the ECG. At this time, the first audible heart sound (often described as a “lubb”) is produced.

Ejection

The semilunar valves open and blood is ejected under great force from the ventricles. At this point, the pressure in the ventricles exceeds the pressure in the pulmonary artery and aorta, and blood is pushed into these vessels. This rapid ejection is characterized by a marked increase in ventricular and aortic pressure. The T wave of the ECG appears during the later, long phase of reduced ejection. You might think of this as the tail end of the contraction. However, a considerable quantity of blood, called the residual volume, remains in the ventricles even at the end of the ejection period. In heart failure, the residual volume remaining in the ventricles may greatly exceed the volume ejected into the aorta and pulmonary trunk.

Ventricular Relaxation

Diastole—the relaxation of the ventricles—begins with this period between closing of the semilunar valves and the opening of the atrioventricular valves. At the end of ventricular contraction, the semilunar valves close so that blood cannot re-enter back into the ventricles from the great vessels. The second heart sound (described as a “dupp”) is now heard.

The atrioventricular valves do not open until the pressure in the atrial chambers exceeds the pressure in the relaxed ventricles. The result is a dramatic fall in intraventricular pressure—but no change in blood volume. This is an isovolumetric phase—both sets of valves are closed.

Passive Ventricular Filling

The continuing return of venous blood from the venae cavae and the pulmonary veins increases pressure within both atria until the atrioventricular valves are forced open. When this happens, blood rushes into the relaxed ventricles. This rapid influx of blood lasts only about 0.1 second but results in a

FIGURE 18-5 The cardiac cycle. The five steps of the heart’s pumping cycle described in the text are shown as a series of changes in the heart wall and valves. The term isovolumetric means that the volume remains constant.

dramatic increase in the volume of blood in the ventricle. The abrupt inflow of blood that occurs immediately after opening of the AV valves is followed by a slow and continuous flow of venous blood into the atria. This blood then flows through the open AV valves and into the ventricles, slowly building up the blood pressure and volume within the ventricles.

Heart Sounds

The first “lubb” or systolic sound is caused largely by the contraction of the ventricles and by the closing atrioventricular valves. It is longer and lower than the second or diastolic sound, which is short and sharp. Vibrations of the closing semilunar valves cause this second “dupp” sound.

Heart sounds have clinical significance and can provide information about the valves. Any variation from normal “lubb-dupp” sounds may suggest imperfect valve function. A heart murmur is one commonly heard type of abnormal heart sound. Sometimes it is described as a “swishing” sound. This may indicate an incomplete closing of the valves or stenosis (constriction or narrowing) of the valves.

6. Briefly outline the steps of the cardiac cycle.

7. When are heart sounds of medical importance?

PRIMARY PRINCIPLE OF CIRCULATION

In order for blood to flow within the circulatory system, there must be a gradient from high pressure to low pressure (Figure 18-6). This is sometimes called the primary principle of circulation. For example, blood enters an arteriole at 85 mm Hg and leaves at 35 mm Hg. The blood thus moves down a pressure gradient (from 85 mm Hg to 35 mm Hg) as it flows through the arteriole. The pressure difference drives the flow of blood.

ARTERIAL BLOOD PRESSURE

High pressure in the arteries must be maintained to keep blood flowing through the circulatory system. The volume of blood within the arteries largely determines arterial blood pressure. Thus, an increase in arterial blood volume tends to increase arterial pressure. Likewise, a decrease in arterial volume tends to decrease arterial pressure. However, many factors determine arterial pressure through their influence on arterial volume. Two of the most important, cardiac output and peripheral resistance, are directly proportional to blood volume, as we will see below.

FIGURE 18-6 The primary principle of circulation. Fluid always travels from an area of high pressure to an area of low pressure. Water flows from an area of high pressure in the tank (100 mm Hg) toward the area of low pressure above the bucket (0 mm Hg). Blood tends to move from an area of high average pressure at the beginning of the aorta (100 mm Hg) toward the area of lowest pressure at the end of the venae cavae (0 mm Hg). Blood flow between any two points in the circulatory system can always be predicted by the pressure gradient.

Cardiac Output

Cardiac output (CO) is the amount of blood that flows out of a ventricle per unit of time. For example, the resting cardiac output from the left ventricle into the systemic arteries is about 5,000 ml/min. The cardiac output influences the flow rate to the various organs of the body. For the sake of our discussion, we will focus on the cardiac output from the left ventricle into the systemic loop.

Cardiac output is determined by the volume of blood pumped out of a ventricle by each beat (stroke volume or SV) and by heart rate (HR). Because contraction of the heart is called systole, sometimes the volume of blood pumped by one contraction is called the systolic discharge. Stroke volume, or volume pumped per heartbeat, is one of two major factors that determine cardiac output. CO can be determined by the following equation:

SV

(

volume

/

beat

)

×

HR

(

beats

/

min

)

=

CO

(

volume

/

min

)

Thus the greater the stroke volume, the greater the CO (but only if the heart rate remains constant). Anything that changes the rate of the heartbeat or its stroke volume tends to change CO. This means that anything that makes the heart beat faster or stronger (increases its stroke volume) tends to increase CO and therefore arterial blood volume and pressure. Conversely, anything that causes the heart to beat more slowly or more weakly (decreases its stroke volume) tends to decrease CO, arterial volume, and blood pressure.

The following sections, and Figure 18-7, summarize a few of the major factors that affect cardiac output.

Factors that Affect Stroke Volume

Mechanical, neural, and chemical factors regulate the strength of the heartbeat and therefore its stroke volume.

One mechanical factor that helps determine stroke volume is the length of the myocardial fibers at the beginning of ventricular contraction. According to the Frank-Starling mechanism, the longer or more stretched the heart fibers are at the beginning of contraction (up to a critical limit), the stronger is their contraction. The more blood returned to the heart per minute, the more stretched will be their fibers. This will lead to stronger contractions and a larger volume of blood ejected with each contraction.

However, if too much blood stretches the heart beyond a certain critical limit, the myocardial muscle seems to lose its elasticity. As a result the heart contracts less vigorously.

We can now see that the heart pumps out what it receives. That is, within certain limits, the strength of myocardial contraction matches the pumping load. This is contrary to most mechanical pumps that do not adjust themselves to their input with every stroke. In the case of a human heart, under ordinary conditions, it automatically adjusts output (stroke volume) to input (venous return to the heart).

Other factors that influence stroke volume are neural and endocrine chemical factors. Norepinephrine (released by sympathetic fibers in the cardiac nerve) and epinephrine (released into the blood by the adrenal medulla) can both increase the strength of contraction, or contractility, of the myocardium. This increased contractility of the heart muscle forces more blood volume out of the heart per cardiac stroke, thus increasing the stroke volume.

Factors that Affect Heart Rate

Although the sinoatrial node normally initiates each heartbeat, the heart rate it sets can be altered. In fact, various factors can and do change the rate of the heartbeat. One major modifier is the ratio of sympathetic and parasympathetic impulses conducted to the node per minute. This is because autonomic control of heart rate is the result of opposing influences between the parasympathetic (chiefly vagus) and sympathetic (cardiac nerve) stimulation. The parasympathetic stimulation is inhibitory—mediated by acetylcholine released by the vagus nerve. The sympathetic stimulation is stimulatory—mediated by the release of norepinephrine at the distal end of the cardiac nerve.

Cardiac Pressoreflexes

Receptors sensitive to changes in pressure (baroreceptors) are located in two places near the heart. The aortic baroreceptors and the carotid baroreceptors send afferent nerve fibers to cardiac control centers in the medulla oblongata. These stretch

FIGURE 18-7 Factors affecting cardiac output.

receptors, located in the aorta and carotid sinus, respectively, are vitally important to controlling heart rate. Baroreceptors operate with integrators in the cardiac control centers in negative feedback loops called pressoreflexes. These oppose changes in pressure by adjusting heart rate.

Other Reflexes that Influence Heart Rate

Reflexes involving important factors such as emotions, exercise, hormones, blood temperature, pain, and stimulation of various exteroceptors also influence heart rate.

Anatomy homework help

ACTIVE LEARNING TEMPLATES

System Disorder
STUDENT NAME _____________________________________

DISORDER/DISEASE PROCESS __________________________________________________________ REVIEW MODULE CHAPTER ___________

ACTIVE LEARNING TEMPLATE:

ASSESSMENT SAFETY
CONSIDERATIONS

PATIENT-CENTERED CARE

Alterations in
Health (Diagnosis)

Pathophysiology Related
to Client Problem

Health Promotion and
Disease Prevention

Risk Factors Expected Findings

Laboratory Tests Diagnostic Procedures

Complications

Therapeutic Procedures Interprofessional Care

Nursing Care Client EducationMedications

  1. STUDENT NAME:
  2. DISORDERDISEASE PROCESS:
  3. REVIEW MODULE CHAPTER:
  4. Pathophysiology Related to Client Problem:
  5. Health Promotion and Disease Prevention:
  6. Risk Factors:
  7. Expected Findings:
  8. Laboratory Tests:
  9. Diagnostic Procedures:
  10. Nursing Care:
  11. Therapeutic Procedures:
  12. Medications:
  13. Client Education:
  14. Interprofessional Care:
  15. Alterations in Health:
  16. Safety Considerations:
  17. Complications:

Anatomy homework help

ACTIVE LEARNING TEMPLATES

System Disorder
STUDENT NAME _____________________________________

DISORDER/DISEASE PROCESS __________________________________________________________ REVIEW MODULE CHAPTER ___________

ACTIVE LEARNING TEMPLATE:

ASSESSMENT SAFETY
CONSIDERATIONS

PATIENT-CENTERED CARE

Alterations in
Health (Diagnosis)

Pathophysiology Related
to Client Problem

Health Promotion and
Disease Prevention

Risk Factors Expected Findings

Laboratory Tests Diagnostic Procedures

Complications

Therapeutic Procedures Interprofessional Care

Nursing Care Client EducationMedications

ATELECTASIS 05

Anatomy homework help


APA Formatting for the Course Paper 2022

• Format all Application Assignments and the Course Paper with double-spacing.

• Use Times New Roman 12-point font.

• Use left margin text alignment, NOT justified text.

• Using hanging indent for any references placed at the end of an assignment.

• If more than one reference is used, place them alphabetically by the author’s last

name (or title of the source when no author is given).

Listing the Textbook as a Reference at the end of an Assignment:

Cohen, R. & Sherman, D. (2020). Theatre Brief, 12th ed. New York, NY: McGraw-Hill.

Listing the Script:

Kaufman, M., and members of the Tectonic Theatre. (2002) The Laramie Project. Dramatist Play Service, Inc. https://www.dramatists.com/The+Laramie+Project.

Listing a Video Recording of a Live Theatre Performance:

Bousel, S. (Director). (2018). LCTC’s The Laramie Project. [Video]. YouTube. https://www.youtube.com/watch?v=JOCMonXXuqQ

Parenthetical References:

Parenthetical references are embedded citations used within your assignment’s text to

identify ideas that are not your own (paraphrased info read in a textbook) or direct

quotation (words lifted from a text)

Here are a few different ways to use embedded citation within the text of an

assignment:

Cohen & Sherman (2020) note in chapter 5 that scenic designers consider “the words of the text and the images in their minds” before beginning to sketch scenery (p. 88).

OR

According to Robert Cohen and Donovan Sherman (2020), “Scenic designers begin their work with the words of the text and the images in their minds….” (p. 88).

NOTE: For more detailed information about APA style, digitally visit the https://stevenson.libguides.com/apastyle

Anatomy homework help

Chapter 3

The Skeletal System

Structures and Functions of the Skeletal System (1 of 2)

Bones

Act as the framework of the body

Support and protect the internal organs

Joints

Work in conjunction with muscles, ligaments, and tendons

Make possible the wide variety of body movements

Calcium

Mineral required for normal nerve and muscle function; is stored in bones

Red bone marrow

Plays an important role in the formation of blood cells

Located within spongy bone

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

2

Structures and Functions of the Skeletal System (2 of 2)

The Formation of Bones

A newborn’s skeleton

Begins as fragile membranes and cartilage

Ossification

Starts turning into bone

Continues through adolescence

After growth is complete, new bone formation continues

Osteoclast cells break down old or damaged bone

Osteoblast cells help rebuild the bone

Ossification repairs minor damage from normal activity and also repairs bones after injuries, such as fractures

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

3

The Structure of Bones (1 of 4)

The Tissues of Bone

Bone is the form of connective tissue

Second hardest tissue in the human body

Capable of growth, healing, and reshaping itself

Compact bone, also known as cortical bone

Dense, hard, and very strong bone

Forms the protective outer layer of bones

Spongy bone, also known as cancellous bone

Porous (“sponge-like”), making it lighter and weaker than compact bone; more susceptible to fractures

Commonly contains red bone marrow

Long bones include femur and humerus

Short bones include the wrist and ankle

Anatomic features of a typical long bone.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

4

The Structure of Bones (2 of 4)

The Tissues of Bone

Medullary cavity

Central cavity located in the shaft of long bones and surrounded by compact bone

Red and yellow bone marrow stored here

Endosteum

Tissue that lines the medullary cavity

Bone Marrow

Red bone marrow is a hematopoietic tissue

Located within the spongy bone

Manufactures red blood cells, hemoglobin, white blood cells, and thrombocytes

Yellow bone marrow functions as a fat storage area

Gradually replaces about half of red bone marrow after early adolescence

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

5

The Structure of Bones (3 of 4)

Cartilage

Smooth, rubbery, blue-white connective tissue

Acts as a shock absorber between bones

Makes up the flexible parts of the skeleton, such as the outer ear and tip of the nose

Articular cartilage

Covers the surfaces of bones where they articulate

Makes smooth joint movement possible

Protects the bones from rubbing against each other

Meniscus

Curved, fibrous cartilage found in some joints

Examples: knee and temporomandibular joint of the jaw

A lateral view of the knee showing the structures of a synovial joint and bursa.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

6

The Structure of Bones (4 of 4)

Anatomic Landmarks of Bones

Diaphysis: shaft of a long bone

Epiphyses: wider ends of long bones such as the femurs of the legs

Proximal epiphysis: end of the bone located nearest to the midline of the body

Distal epiphysis: end of the bone located farthest away from the midline of the body

Foramen: opening through which blood vessels, nerves, and ligaments pass

Example: foramen magnum

Process: normal projection on the surface of a bone

Most commonly serves as an attachment for a muscle or tendon

Example: mastoid process

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

7

Joints (1 of 3)

Joints

Also known as articulations

Place of union between two or more bones

Classified by construction or based on the degree of movement they allow

Fibrous Joints

Hold the bones tightly together

Consist of inflexible layers of dense connective tissue

Known as sutures in adults, allow little or no movement

Called fontanelles or soft spots in newborns and very young children, these joints allow for passage through the birth canal and for growth of the skull during the first year

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.02: Describe three types of joints.

8

Joints (2 of 3)

Cartilaginous Joints

Allow only slight movement

Consist of bones connected entirely by cartilage

Breastbone

Where the ribs connect to the sternum

Allow movement during breathing

Pubic symphysis

Allows some movement to facilitate childbirth

Located between the pubic bones in the anterior (front) of the pelvis

Anterior view of the pelvis.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.02: Describe three types of joints.

9

Joints (3 of 3)

Synovial Joints

Ball-and-socket joints

Allow a wide range of movement in many directions

Examples: hips and shoulders

Hinge joints

Allow movement primarily in one direction or plane

Examples: knees and elbows

Components of Synovial Joints

Synovial capsule

Synovial membrane

Synovial fluid

Ligaments and bursa

Examples of synovial joints. (A) Ball-and-socket joint of the hip. (B) Hinge joint of the elbow. (C) Hinge joint of the knee.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.02: Describe three types of joints.

10

The Skeleton (1 of 11)

Typical Adult Skeleton

Consists of approximately 206 bones

Divided into axial and appendicular

Axial Skeleton

Protects major organs of the nervous, respiratory, and circulatory systems

80 bones of the head and body organized into five parts:

Bones of the skull

Ossicles (bones) of the middle ear

Hyoid bone

Rib cage

Vertebral column

Anterior and posterior views of the human skeleton.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.03: Differentiate between the axial and appendicular skeletons.

11

The Skeleton (2 of 11)

Appendicular Skeleton

Makes body movement possible

Protects the organs of digestion, excretion, and reproduction

Consists of 126 bones

Upper extremities (shoulders, arms, forearms, wrists, and hands)

Lower extremities (hips, thighs, legs, ankles, and feet)

Appendicular means referring to an appendage

An appendage is anything that is attached to a major part of the body

An extremity is the terminal end of a body part such as an arm or leg

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.03: Differentiate between the axial and appendicular skeletons.

12

The Skeleton (3 of 11)

Bones of the Skull

Bones of the cranium

Frontal, parietal, occipital, external auditory meatus sphenoid, and ethmoid

Enclose and protect the brain

Auditory ossicles

Malleus, incus, and stapes

Three tiny bones located in the middle ear

Bones of the face

Nasal, zygomatic, maxillary, palatine, lacrimal, inferior conchae, vomer, and mandible

Anterior view of the adult human skull.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

13

The Skeleton (4 of 11)

Thoracic Cavity

Also called rib cage; consists of ribs and sternum

Bony structure that protects the heart and lungs

Ribs (12 pairs)

True ribs: first seven pairs attached anteriorly to the sternum

False ribs: Next three pairs attached anteriorly to cartilage that connects to the sternum

Floating ribs: only attached posteriorly to the vertebrae but are not attached anteriorly

Sternum (also known as the breast bone)

Manubrium: forms the upper portion of the sternum

Body of the sternum or gladiolus: forms the middle portions of the sternum

Xiphoid process: cartilage that forms the lower portion of the sternum

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

14

The Skeleton (5 of 11)

Shoulders and Arms

Shoulders

Clavicle (collarbone)

Scapula (shoulder blade)

Acromion (extension of scapula)

Arms

Humerus (bone of upper arm)

Radius (smaller, shorter forearm bone)

Ulna (larger, longer forearm bone)

Olecranon (proximal tip of the ulna; commonly known as the funny bone)

Anterior view of the ribs, shoulder, and arm. (Cartilaginous structures are shown in blue.)

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

15

The Skeleton (6 of 11)

The Wrists, Hands, and Fingers

Carpals

Eight bones that form the wrist

Form a narrow bony passage known as the carpal tunnel

Metacarpals

Five bones that form the palms of the hand

Phalanges (singular, phalanx)

14 bones of the fingers

Each finger has three: distal (outermost), middle, and proximal (nearest the hand)

The thumb has two bones (distal and proximal phalanges)

Superior view of the bones of the lower left arm, wrist, and hand.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

16

The Skeleton (7 of 11)

The Spinal Column (Vertebral Column)

Protects the spinal cord and supports the
head and body

The spinal column consists of 26 vertebrae

Each of these bony units is known as a vertebra

Structures of the vertebrae

Body of the vertebra: anterior portion

Lamina: posterior portion

Vertebral foramen: opening in the middle

Characteristics of a typical vertebra.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

17

The Skeleton (8 of 11)

The Spinal Column (vertebral column)

Intervertebral disks

Made of cartilage and pads of tissue

Separate and cushion the vertebrae from each other

Allow for movement of the spinal column

Types of vertebrae

Cervical: first seven vertebrae; form the neck

Thoracic: T1 through T12; have ribs attached

Lumbar: L1 through L5; form inward curve

Sacrum: triangular bone near base of spine

Coccyx: tailbone; forms the end of the spine

Lateral view of the vertebral column.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

18

The Skeleton (9 of 11)

The Pelvis

Bony pelvis

Protects internal organs and supports the lower extremities

Includes sacrum, coccyx, and pelvic girdle (ilium, ischium, and pubis)

Sacroiliac

Slightly movable articulation between the sacrum and posterior portion of the ilium

Pubic symphysis

Cartilaginous joint that unites the left and right pubic bones

Acetabulum

Also known as the hip socket

Structures of the proximal end of the femur and the acetabulum (hip socket).

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

19

The Skeleton (10 of 11)

The Legs and Knees

Femurs

Largest bones in the body

Knees

Patella (kneecap)

Popliteal: space behind knee

Cruciate ligaments: shaped like a cross; make possible the movements of the knee

Lower legs

Tibia (shinbone): larger, anterior weight-bearing bone of the lower leg

Fibula: smaller of the two bones of the lower leg

Lateral view of bones of the lower extremity.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

20

The Skeleton (11 of 11)

The Ankles

Joints that connect the lower leg and foot

Tarsal bones: similar to, but bigger than, the wrist

Malleolus: rounded bony projection

Talus: articulates with the tibia and fibula

Calcaneus: heel bone; largest of the tarsal bones

The Feet and Toes

Metatarsals form the part of the foot to which the toes are attached

Phalanges are the bones of the toes

The great toe has two phalanges

Each of the other toes has three phalanges

Bones of the right ankle and foot. (A) Lateral view.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.01: Identify and describe the major functions and structures of the skeletal system.

21

Medical Specialties Related to the Skeletal System (1 of 2)

Chiropractor

Holds a Doctor of Chiropractic (DC) degree

Specializes in the manipulative treatment of disorders originating from misalignment of the spine

Orthopedic surgeon

Also known as an orthopedist

Physician specializing in diagnosing and treating diseases and disorders involving the bones, joints, and muscles

Osteopath

Holds a Doctor of Osteopathy (DO) degree

Uses traditional forms of medical treatment in addition to specializing in treating health problems by spinal manipulation

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.04: Identify the medical specialists who treat disorders of the skeletal system.

22

Medical Specialties Related to the Skeletal System (2 of 2)

Podiatrist

Holds a Doctor of Podiatry (DP) or Doctor of Podiatric Medicine (DPM) degree

Specializes in diagnosing and treating disorders of the foot

Rheumatologist

Physician specializing in the diagnosis and treatment of arthritis and disorders such as osteoporosis, fibromyalgia, and tendinitis that are characterized by inflammation in the joints and connective tissues

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.04: Identify the medical specialists who treat disorders of the skeletal system.

23

Pathology of the Skeletal System (1 of 11)

Joints

Ankylosis: loss or absence of mobility

Adhesive capsulitis: frozen shoulder; ankylosis caused by adhesions

Arthrosclerosis: stiffness of the joints

Baker’s cyst: popliteal cyst; fluid-filled sac behind the knee

Bursitis: inflammation of the bursa

Chondromalacia: abnormal softening of cartilage

Costochondritis: inflammation of cartilage connecting the ribs to the sternum

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.05: Recognize, define, spell, and pronounce the primary terms related to the pathology and the diagnostic and treatment procedures of the skeletal system.

24

Pathology of the Skeletal System (2 of 11)

Joints

Hallux valgus: bunion; abnormal enlargement of the base joint of the great toe

Hemarthrosis: blood within a joint

Polymyalgia rheumatica (PMR): inflammatory disorder of muscles and joints

Sprain: ligament that connects bones to a joint is wrenched or torn

Synovitis: inflammation of the synovial membrane

Joint Dislocation

Dislocation: luxation; total displacement of a bone from its joint

Subluxation: partial displacement of a bone from its joint

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.05: Recognize, define, spell, and pronounce the primary terms related to the pathology and the diagnostic and treatment procedures of the skeletal system.

25

Pathology of the Skeletal System (3 of 11)

Arthritis

Osteoarthritis (OA): wear-and-tear arthritis; degenerative joint disease

Osteophytes: formation of bone spurs

Spondylosis: spinal osteoarthritis

Gout: gouty arthritis; deposits of urate crystals in the joints

Pseudogout: buildup of calcium pyrophosphate crystals

Rheumatoid arthritis (RA): chronic autoimmune disorder

Joints and some organs of other body systems are attacked

Ankylosing spondylitis (AS): inflammation of joints between vertebrae

Juvenile idiopathic arthritis (JIA): formerly juvenile rheumatoid arthritis

Psoriatic arthritis (PsA): Affects about 20% of people with psoriasis

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.05: Recognize, define, spell, and pronounce the primary terms related to the pathology and the diagnostic and treatment procedures of the skeletal system.

26

Pathology of the Skeletal System (4 of 11)

The Spinal Column

Herniated disk: slipped or ruptured disk

Lumbago: low back pain (LBP)

Spondylolisthesis: forward slipping movement of lower lumbar vertebrae on
the vertebra or sacrum below it

Spina bifida: congenital defect; spinal canal fails to close completely

Curvatures of the spine

Kyphosis: hunchback; outward curvature

Lordosis: swayback; forward curvature

Scoliosis: lateral curvature

Abnormal curvatures of the spine. (A) Kyphosis. (B) Lordosis. (C) Scoliosis. (Normal curvatures are shown in shadow.)

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.05: Recognize, define, spell, and pronounce the primary terms related to the pathology and the diagnostic and treatment procedures of the skeletal system.

27

Pathology of the Skeletal System (5 of 11)

Bones

Avascular necrosis: osteonecrosis; insufficient blood flow to bone tissue

Osteitis: inflammation of a bone

Osteomalacia: adult rickets; abnormal bone softening; vitamin D deficiency

Osteomyelitis: inflammation of the bone marrow and adjacent bone

Paget’s disease: chronic bone disease of unknown cause

Periostitis: inflammation of the periosteum; often associated with shin splints

Radiculopathy: pinched nerve; compression of a nerve in the spine

Rickets: defective bone growth resulting from vitamin D deficiency in children

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.05: Recognize, define, spell, and pronounce the primary terms related to the pathology and the diagnostic and treatment procedures of the skeletal system.

28

Pathology of the Skeletal System (6 of 11)

Bones

Spinal stenosis: narrowing of the spaces within the spine

Short stature: formerly known as dwarfism

Caused by more than 200 different conditions

Some adults of short stature prefer to be referred to as little people

Clubfoot: talipes

Congenital deformity of the foot involving the talus

Bone tumors

Primary bone cancer: relatively rare malignant tumor originating in the bone

Secondary bone cancer: bone metastasis; cancer spreads to bones from other organs

Multiple myeloma: cancer that occurs in blood-making plasma cells of red bone marrow

Osteochondroma: benign bony projection covered with cartilage

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.05: Recognize, define, spell, and pronounce the primary terms related to the pathology and the diagnostic and treatment procedures of the skeletal system.

29

Pathology of the Skeletal System (7 of 11)

Osteoporosis and Osteopenia Compared

Osteoporosis (OP)

Marked loss of bone density

Increase in bone porosity frequently associated with aging

Most common in women over 50 years old; decrease in estrogen after menopause

Osteopenia

Thinner-than-average bone density

Condition of someone who does not yet have osteoporosis

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.05: Recognize, define, spell, and pronounce the primary terms related to the pathology and the diagnostic and treatment procedures of the skeletal system.

30

Pathology of the Skeletal System (8 of 11)

Osteoporosis-Related Fractures

Compression fracture

Occurs when the bone is pressed together (compressed) on itself

Colles fracture

Broken wrist

Often occurs when a person tries to stop a fall by landing on the hand

Osteoporotic hip fracture

Broken hip

Usually caused by weakening of the bones due to osteoporosis

Can occur either spontaneously or as the result of a fall

A Colles fracture of the left wrist.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.05: Recognize, define, spell, and pronounce the primary terms related to the pathology and the diagnostic and treatment procedures of the skeletal system.

31

Pathology of the Skeletal System (9 of 11)

Fractures

Broken bones

Described in terms of complexity

Closed fracture

Simple fracture or a complete fracture

No open wound in the skin

Open fracture

Compound fracture

Open wound in the skin

Comminuted fracture

Bone is splintered or crushed

Types of bone fractures. (A) Incomplete. (B) Closed (simple, complete). (C) Open (compound). (D) Comminuted.

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.05: Recognize, define, spell, and pronounce the primary terms related to the pathology and the diagnostic and treatment procedures of the skeletal system.

32

Pathology of the Skeletal System (10 of 11)

Fractures

Incomplete fracture

Bone does not break into two separate pieces

Occurs primarily in children

Greenstick fracture

One side of the bone is broken and the other side is only bent

Buckle fracture (torus fracture)

Affected side of the bone is compressed and buckles but does not break

Oblique fracture

Occurs at an angle across the bone

Pathologic fracture

Bone weakened by osteoporosis or cancer breaks under normal strain

Schroeder/Ehrlich/Schroeder Smith/Ehrlich, Medical Terminology for Health Professions, 9th Edition. © 2022 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.

Learning Objective 3.05: Recognize, define, spell, and pronounce the primary terms related to the pathology and the diagnostic and treatment procedures of the skeletal system.

33

Pathology of the Skeletal System (11 of 11)

Fractures

Spiral fracture

Complete fracture in which the bone has been twisted apart

Occurs as the result of a severe twisting motion

Stress fracture (overuse injury)

Small crack in bone that develops from chronic, excessive impact

Transverse fracture

Occurs straight across, perpendicular to the shaft of the bone

Additional terms associated with fractures

Fat embolus: fat cells from yellow bone marrow are released into the blood

Crepitation (crepitus): grating sound heard when ends of a broken bone move together<

Anatomy homework help

The Soccer Mom:
A Case Study on the Nervous System
by
Jennifer Bolognese, Misti Coronel, Anita Intorre, and
Phil Stephens
Biology Department
Villanova University

Part I—At the Soccer Game
Tirty-two-year-old Phyllis Jackson was sitting on the bench at the side of the soccer field, sipping a bottle of
Gatorade. Her husband, Steven, sat next to her with a concerned expression.

“I’m really worried about you, honey,” he said.

“I’m just a little dehydrated; I’ll be fi ne.”

“If this were the first incident, then maybe I’d agree with you. But your boss has been on your case about
your lack of concentration at work, you forgot to pick up the kids from school last week, and quite frankly,
you haven’t exactly been yourself with me lately. Now you’re having fainting spells during games? Something
doesn’t seem right.”

“I know things haven’t been going well for me lately, but I don’t know why. I try so hard at work, at home,
with the kids, to be a good wife. So maybe all this stress has made me a little unfocused and disoriented.
What do you want me to do about it?” Phyllis said, blinking back tears.

“I think you should see a doctor,” Steven replied, putting his arm around her and drawing her close. “T e
kids are getting worried, too.”

Phyllis sighed. “Alright, if it will make you feel better. I really just think I need some time to relax, though.”

“Well… I could drop the kids off at my sister’s tonight; that would give us a little free time…”

“Tat’s really thoughtful of you. I could definitely use a quiet night at home, maybe even go to bed early.”

Steven seemed disappointed.

Questions
. What problems does Phyllis seem to be experiencing?
. Which of these problems could be caused by dehydration?
. Which of these problems might make you consider that there’s something more going on? Why?
. Suppose Phyllis does have a more serious problem. Can you think of any neurological problems

that could be the cause of these symptoms?

“The Soccer Mom” by Bolognese, Coronel, Intorre and Stephens Page 1

Part II—The Doctor Visit
“So, what seems to be the problem, Mrs. Jackson?” Dr. Warner asked Phyllis.

“My husband wanted me to come in and see you after I fainted during my soccer game Saturday. I’ve also
been having some problems at work, but I think I’m just stressed.”

“What kinds of problems have you been having at work?”

“It’s been hard to concentrate on tasks. I’ve also had some problems typing—I’ve been making more errors
than usual, and oftentimes my fingers will go numb.”

“I see,” said Dr. Warner, taking a few notes on his clipboard. “According to my records you are not on any
long term medication. Have you noticed any problems outside of work?”

“Well, my husband has been complaining about our personal life lately. And last week, I completely forgot
that I was supposed to pick up our two daughters after school. I’ve been feeling really tired lately; even my
coordination seems off .”

“How long has this been going on for?”

“A few weeks, but this isn’t the first time. Tese problems seem to come and go, but it’s getting to the point
where I can’t just ignore them anymore. I don’t know, maybe I’m just depressed.”

“Why do you say that?”

“My mother suffered from depression throughout my childhood.”

“Well, depression certainly could cause some of the symptoms you’re experiencing,” Dr. Warner said
thoughtfully. “Is there a history in your family of any neurological disorders?”

“I don’t think so. I have some vague recollection of my grandfather in a wheelchair when I was really young,
but I don’t know what was wrong with him.”

“Okay,” said the doctor, nodding. “Well, the few preliminary tests we’ve run show that you are not pregnant,
and that you are not going through menopause. I’d like to send you to see Dr. Trush, a friend and colleague
of mine. She is a neurologist at the local hospital and she will run a few tests to explore your symptoms a
little further.”

Questions
. What new signs or symptoms have been revealed?
. Could any of Phyllis’s symptoms be attributed to depression? If so, which?
. What neurotransmitters are thought to be involved in depression?
. What neurological disorders could have put her grandfather in a wheelchair?
. Could any of these neurological disorders explain one or more of Phyllis’ symptoms?
. Could Phyllis have inherited any of these disorders?
. If you were in Dr. Warner’s position, what tests might you suggest to confirm (or not) this

diagnosis?

“The Soccer Mom” by Bolognese, Coronel, Intorre and Stephens Page 2

Part III—Diagnostic Tests
Dr. Trush looked over the results of Phyllis’s Magnetic Resonance Imaging (mri) and evoked potential tests.
She was thinking how glad she was that Steven had accompanied Phyllis on this visit as she showed them the
MR images of Phyllis’ brain.

“Te machine took pictures of Phyllis’ brain in slices. Te dark areas are the brain tissue, Phyllis, and the
white areas in the middle and around the outside are the cerebrospinal fl uid.”

“Is that normal? Am I ok?” Phyllis asked. “And what are those little white dots in the tissue?”

“Te white dots are what concerned me,” replied the doctor. “So we did another type of mri, called dark fl uid,
so that your cerebrospinal fluid would not show up white.”

“But I still see the white dots in my brain tissue. What does that mean?”

Te doctor looked down, knowing that this was never an easy thing to tell a patient.

“I am afraid that this indicates that there are plaques or scars in your brain, and that you may have multiple
sclerosis.”

Tears began to form in her eyes as Phyllis squeezed her husband’s hand.

“I am afraid that the evoked potential test and the elevated levels of myelin basic protein in you cerebrospinal
fluid indicate the same thing.”

Questions
. Test your knowledge of the function of chemical synapses by filling in the flow diagram on the

next page.
. What type of cell is myelin?
. What is the function of myelin in nerve cells?
. In myelinated axons, where are action potentials generated?
. Where, then, are voltage gated sodium channels concentrated in myelinated axons?
. What happens to myelin in people who suffer from multiple sclerosis?
. Why is there an elevated level of myelin basic protein in the cerebrospinal fl uid?
. What would be the effect on action potential conduction at a region of axon where the disease had

its eff ect?
. What effect would this have on the coordination of movements if this took place in areas involved

in motor control of fi nger movements?

“The Soccer Mom” by Bolognese, Coronel, Intorre and Stephens Page 3

An action potential in an
excitatory presynaptic nerve.

An _____ in the dendrites of
the postsynaptic nerve.

This spreads passively to the
___________.

Depolarization of this region
opens voltage-gated ______

channels.

Suffi cient membrane
depolarization to _________

opens enough of these
channels to produce an

action potential.

Non-myelinated axon Myelinated axon

The currents associated with
the action potential spread to

the ______ region of the axon.

The currents associated with
the action potential spread to

the next ________.

The action potential travels
down the axon to the

___________.

“The Soccer Mom” by Bolognese, Coronel, Intorre and Stephens Page 4

Part IV—The Diagnosis
Dr. Trush informed Phyllis that she was probably suffering from the relapsing-remitting form of multiple
sclerosis (ms), in which relapses of symptoms are separated by periods of remission. ms is a disorder in which
the myelination of axons is degraded due to unknown factors. Te most commonly accepted explanation is
that ms is an autoimmune disorder in which myelin in the central nervous system is attacked by the body’s
own immune system. Tere is no known cure for multiple sclerosis.

Dr. Trush ordered physical therapy, weekly injections of interferon beta, and corticosteroids. In addition,
she suggested that Phyllis and Steven begin marriage counseling to help them deal with the changes in their
lifestyle caused by this disorder.

Questions
. During remission, axons affected by the disorder regain their function. If voltage-gated sodium

channels are concentrated in certain regions of the myelinated axon prior to the disease, what do
you think happens to these sodium channels after multiple sclerosis has had its eff ect?

. How would these three treatments (physical therapy, weekly injections of interferon beta, and
corticosteroids) help to control Phyllis’s symptoms?

Copyright ©  by the National Center for Case Study Teaching in Science.
Originally published // at http://www.sciencecases.org/soccer_mom/soccer_mom.asp
Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work.

“The Soccer Mom” by Bolognese, Coronel, Intorre and Stephens Page 5

Anatomy homework help

he left side of our heart feeds into the systemic circulatory route and the right side feeds into the pulmonary circulatory route (Patton et al., 2011). The systemic side pushes blood to the whole body except the lungs where the left side moves blood back and forth to only the lungs. In order for the heart to achieve proper contraction, it has a conduction system. The heart’s conduction system of the heart includes the sinoatrial node, the atrioventricular node, the AV bundle, and the subendocardial branches (Cleveland Clinic, n.d.). The sinoatrial node which is also called the SA node is located in your right atrium. This node is what sends impulses for your heart to initiate beating. Due to this function, this is sometimes called your heart’s natural pacemaker. The atrioventricular node otherwise known as your AV node is located near the center of your heart. This node is responsible for delaying the SA node’s impulse for a short amount of time to ensure the atria have pushed out all of their blood because it decreases contraction. From the atria, the blood is pushed into the ventricles. The AV bundle is what is stimulated next. The AV bundle is also known as the bundle of his is separated into left and right branches (Conducting System of the Heart – Bundle of His – SA Node, 2019). These bundles send the impulse from the AV node to the subendocardial branches. The right bundle sends it to the subendocardial branches in the right ventricle and the left bundle sends it to the subendocardial branches in the left ventricle. The subendocardial branches are also called Purkinje fibers. The Purkinje fibers are a group of specialized cells. The cells are able to transmit cardiac impulses from the AV nodes to the ventricles. This allows for coordinated contraction through the ventricles. Describe what happens to a person’s heart when they experience a myocardial infarction?

Classmate Question #2:

There is an average of 5 liters of blood in a healthy adult. Men usually have more blood than women but during pregnancy, a woman’s blood volume can increase by 50% (Sharma et al., 2021). Blood volume is regulated by how much sodium and water we intake and how much we excrete (CV Physiology, n.d.). We excrete water and sodium through our kidneys but we can also lose them through our GI tract, skin, and lungs. If our blood volume were to decrease by 5 to 10 percent so would our blood pressure (Betts, 2013). ADH is then released from our pituitary gland. The release of this hormone causes vasoconstriction which helps raise our blood pressure back up. To help restore blood volume this hormone also stimulates aquaporin channels in our kidneys to help restore the volume of water. When blood return to the atria is too elevated cells in the atrial wall secrete ANH (Patton et al., 2011). ANH is called atrial natriuretic hormone. This decreases our blood volume by increasing sodium excretion in the kidneys. When this is stimulated water is also excreted by the kidneys due to the rule of osmosis. The opposite of this would be when the kidneys stop water loss by reabsorbing it from the urine when the antidiuretic hormone is secreted. If there is more antidiuretic hormone present then there is less water excreted from the body which in turn causes an increase in total blood volume. What are two disorders that can affect our total blood volume?

Anatomy homework help

The Soccer Mom:
A Case Study on the Nervous System
by
Jennifer Bolognese, Misti Coronel, Anita Intorre, and
Phil Stephens
Biology Department
Villanova University

Part I—At the Soccer Game
Tirty-two-year-old Phyllis Jackson was sitting on the bench at the side of the soccer field, sipping a bottle of
Gatorade. Her husband, Steven, sat next to her with a concerned expression.

“I’m really worried about you, honey,” he said.

“I’m just a little dehydrated; I’ll be fi ne.”

“If this were the first incident, then maybe I’d agree with you. But your boss has been on your case about
your lack of concentration at work, you forgot to pick up the kids from school last week, and quite frankly,
you haven’t exactly been yourself with me lately. Now you’re having fainting spells during games? Something
doesn’t seem right.”

“I know things haven’t been going well for me lately, but I don’t know why. I try so hard at work, at home,
with the kids, to be a good wife. So maybe all this stress has made me a little unfocused and disoriented.
What do you want me to do about it?” Phyllis said, blinking back tears.

“I think you should see a doctor,” Steven replied, putting his arm around her and drawing her close. “T e
kids are getting worried, too.”

Phyllis sighed. “Alright, if it will make you feel better. I really just think I need some time to relax, though.”

“Well… I could drop the kids off at my sister’s tonight; that would give us a little free time…”

“Tat’s really thoughtful of you. I could definitely use a quiet night at home, maybe even go to bed early.”

Steven seemed disappointed.

Questions
. What problems does Phyllis seem to be experiencing?
. Which of these problems could be caused by dehydration?
. Which of these problems might make you consider that there’s something more going on? Why?
. Suppose Phyllis does have a more serious problem. Can you think of any neurological problems

that could be the cause of these symptoms?

“The Soccer Mom” by Bolognese, Coronel, Intorre and Stephens Page 1

Part II—The Doctor Visit
“So, what seems to be the problem, Mrs. Jackson?” Dr. Warner asked Phyllis.

“My husband wanted me to come in and see you after I fainted during my soccer game Saturday. I’ve also
been having some problems at work, but I think I’m just stressed.”

“What kinds of problems have you been having at work?”

“It’s been hard to concentrate on tasks. I’ve also had some problems typing—I’ve been making more errors
than usual, and oftentimes my fingers will go numb.”

“I see,” said Dr. Warner, taking a few notes on his clipboard. “According to my records you are not on any
long term medication. Have you noticed any problems outside of work?”

“Well, my husband has been complaining about our personal life lately. And last week, I completely forgot
that I was supposed to pick up our two daughters after school. I’ve been feeling really tired lately; even my
coordination seems off .”

“How long has this been going on for?”

“A few weeks, but this isn’t the first time. Tese problems seem to come and go, but it’s getting to the point
where I can’t just ignore them anymore. I don’t know, maybe I’m just depressed.”

“Why do you say that?”

“My mother suffered from depression throughout my childhood.”

“Well, depression certainly could cause some of the symptoms you’re experiencing,” Dr. Warner said
thoughtfully. “Is there a history in your family of any neurological disorders?”

“I don’t think so. I have some vague recollection of my grandfather in a wheelchair when I was really young,
but I don’t know what was wrong with him.”

“Okay,” said the doctor, nodding. “Well, the few preliminary tests we’ve run show that you are not pregnant,
and that you are not going through menopause. I’d like to send you to see Dr. Trush, a friend and colleague
of mine. She is a neurologist at the local hospital and she will run a few tests to explore your symptoms a
little further.”

Questions
. What new signs or symptoms have been revealed?
. Could any of Phyllis’s symptoms be attributed to depression? If so, which?
. What neurotransmitters are thought to be involved in depression?
. What neurological disorders could have put her grandfather in a wheelchair?
. Could any of these neurological disorders explain one or more of Phyllis’ symptoms?
. Could Phyllis have inherited any of these disorders?
. If you were in Dr. Warner’s position, what tests might you suggest to confirm (or not) this

diagnosis?

“The Soccer Mom” by Bolognese, Coronel, Intorre and Stephens Page 2

Part III—Diagnostic Tests
Dr. Trush looked over the results of Phyllis’s Magnetic Resonance Imaging (mri) and evoked potential tests.
She was thinking how glad she was that Steven had accompanied Phyllis on this visit as she showed them the
MR images of Phyllis’ brain.

“Te machine took pictures of Phyllis’ brain in slices. Te dark areas are the brain tissue, Phyllis, and the
white areas in the middle and around the outside are the cerebrospinal fl uid.”

“Is that normal? Am I ok?” Phyllis asked. “And what are those little white dots in the tissue?”

“Te white dots are what concerned me,” replied the doctor. “So we did another type of mri, called dark fl uid,
so that your cerebrospinal fluid would not show up white.”

“But I still see the white dots in my brain tissue. What does that mean?”

Te doctor looked down, knowing that this was never an easy thing to tell a patient.

“I am afraid that this indicates that there are plaques or scars in your brain, and that you may have multiple
sclerosis.”

Tears began to form in her eyes as Phyllis squeezed her husband’s hand.

“I am afraid that the evoked potential test and the elevated levels of myelin basic protein in you cerebrospinal
fluid indicate the same thing.”

Questions
. Test your knowledge of the function of chemical synapses by filling in the flow diagram on the

next page.
. What type of cell is myelin?
. What is the function of myelin in nerve cells?
. In myelinated axons, where are action potentials generated?
. Where, then, are voltage gated sodium channels concentrated in myelinated axons?
. What happens to myelin in people who suffer from multiple sclerosis?
. Why is there an elevated level of myelin basic protein in the cerebrospinal fl uid?
. What would be the effect on action potential conduction at a region of axon where the disease had

its eff ect?
. What effect would this have on the coordination of movements if this took place in areas involved

in motor control of fi nger movements?

“The Soccer Mom” by Bolognese, Coronel, Intorre and Stephens Page 3

An action potential in an
excitatory presynaptic nerve.

An _____ in the dendrites of
the postsynaptic nerve.

This spreads passively to the
___________.

Depolarization of this region
opens voltage-gated ______

channels.

Suffi cient membrane
depolarization to _________

opens enough of these
channels to produce an

action potential.

Non-myelinated axon Myelinated axon

The currents associated with
the action potential spread to

the ______ region of the axon.

The currents associated with
the action potential spread to

the next ________.

The action potential travels
down the axon to the

___________.

“The Soccer Mom” by Bolognese, Coronel, Intorre and Stephens Page 4

Part IV—The Diagnosis
Dr. Trush informed Phyllis that she was probably suffering from the relapsing-remitting form of multiple
sclerosis (ms), in which relapses of symptoms are separated by periods of remission. ms is a disorder in which
the myelination of axons is degraded due to unknown factors. Te most commonly accepted explanation is
that ms is an autoimmune disorder in which myelin in the central nervous system is attacked by the body’s
own immune system. Tere is no known cure for multiple sclerosis.

Dr. Trush ordered physical therapy, weekly injections of interferon beta, and corticosteroids. In addition,
she suggested that Phyllis and Steven begin marriage counseling to help them deal with the changes in their
lifestyle caused by this disorder.

Questions
. During remission, axons affected by the disorder regain their function. If voltage-gated sodium

channels are concentrated in certain regions of the myelinated axon prior to the disease, what do
you think happens to these sodium channels after multiple sclerosis has had its eff ect?

. How would these three treatments (physical therapy, weekly injections of interferon beta, and
corticosteroids) help to control Phyllis’s symptoms?

Copyright ©  by the National Center for Case Study Teaching in Science.
Originally published // at http://www.sciencecases.org/soccer_mom/soccer_mom.asp
Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work.

“The Soccer Mom” by Bolognese, Coronel, Intorre and Stephens Page 5

Anatomy homework help

Requirements

Part A

After watching the video, address the first question based on your thoughts supported by research. Support your main points with facts, data, tables/charts/graphs, logic, and/or personal observations. This question should be a minimum of 250 written words in length. Include at least two primary research references in APA format. Four primary references will result in an A for this section of the rubric, three references will be a B, and one reference will be a D. Do not use encyclopedias, dictionaries, or open sources such as Wikipedia as references. Do not use quotes. Put the information in your own words. Post your reply by Tuesday night. Be sure to adequately edit your work before you submit it.

Part B

By Thursday night post 2 well-crafted questions for your classmates to answer. Each question must be at least 200 written words in length and should provide sufficient background to make the questions compelling. Do not ask superficial questions. They should be thoughtful and require an in-depth response. Start each question post with “CLASSMATE QUESTION.Include at least 1 (one) primary research reference in APA format. Three primary references will result in an A for this section of the rubric and two references will be a B. Do not use encyclopedias, dictionaries, or open sources such as Wikipedia as references. Do not use quotes. Put the information in your own words. Be sure to adequately edit your work before you submit it.

Part C

Respond in detail to at least 2 (two) of your classmate’s questions. Each classmate response must be at least 100 written words in length. More is better. When responding to your classmate’s questions you must start with “CLASSMATE RESPONSE.Include at least 1 (one) primary research reference in APA format. Three primary references will result in an A for this section of the rubric and two references will be a B. Do not use encyclopedias, dictionaries, or open sources such as Wikipedia as references. Do not use quotes. Put the information in your own words. These responses may be submitted any time throughout the week. Be concise and do not use fluff. These replies should be well-thought out scholarly answers to the questions. Be sure to adequately edit your work before you submit it.

Word Count

Part A

A: 350 or more written words; B: 300 – 349 written words, C: 250 – 299 written words; D : 200 – 249 written words, F: less than 200 written words.

Part B

A: 250 or more written words; B: 225 – 249 written words;; C: 200 – 224 written words; D: 150 – 199 written words, F: less than 150 written words.

Part C

A: 150 or more written words; B: 125 – 149 written words;; C: 100 – 124 written words; D: 75 – 99 written words, F: less than 75 written words.

Anatomy homework help

he left side of our heart feeds into the systemic circulatory route and the right side feeds into the pulmonary circulatory route (Patton et al., 2011). The systemic side pushes blood to the whole body except the lungs where the left side moves blood back and forth to only the lungs. In order for the heart to achieve proper contraction, it has a conduction system. The heart’s conduction system of the heart includes the sinoatrial node, the atrioventricular node, the AV bundle, and the subendocardial branches (Cleveland Clinic, n.d.). The sinoatrial node which is also called the SA node is located in your right atrium. This node is what sends impulses for your heart to initiate beating. Due to this function, this is sometimes called your heart’s natural pacemaker. The atrioventricular node otherwise known as your AV node is located near the center of your heart. This node is responsible for delaying the SA node’s impulse for a short amount of time to ensure the atria have pushed out all of their blood because it decreases contraction. From the atria, the blood is pushed into the ventricles. The AV bundle is what is stimulated next. The AV bundle is also known as the bundle of his is separated into left and right branches (Conducting System of the Heart – Bundle of His – SA Node, 2019). These bundles send the impulse from the AV node to the subendocardial branches. The right bundle sends it to the subendocardial branches in the right ventricle and the left bundle sends it to the subendocardial branches in the left ventricle. The subendocardial branches are also called Purkinje fibers. The Purkinje fibers are a group of specialized cells. The cells are able to transmit cardiac impulses from the AV nodes to the ventricles. This allows for coordinated contraction through the ventricles. Describe what happens to a person’s heart when they experience a myocardial infarction?

Classmate Question #2:

There is an average of 5 liters of blood in a healthy adult. Men usually have more blood than women but during pregnancy, a woman’s blood volume can increase by 50% (Sharma et al., 2021). Blood volume is regulated by how much sodium and water we intake and how much we excrete (CV Physiology, n.d.). We excrete water and sodium through our kidneys but we can also lose them through our GI tract, skin, and lungs. If our blood volume were to decrease by 5 to 10 percent so would our blood pressure (Betts, 2013). ADH is then released from our pituitary gland. The release of this hormone causes vasoconstriction which helps raise our blood pressure back up. To help restore blood volume this hormone also stimulates aquaporin channels in our kidneys to help restore the volume of water. When blood return to the atria is too elevated cells in the atrial wall secrete ANH (Patton et al., 2011). ANH is called atrial natriuretic hormone. This decreases our blood volume by increasing sodium excretion in the kidneys. When this is stimulated water is also excreted by the kidneys due to the rule of osmosis. The opposite of this would be when the kidneys stop water loss by reabsorbing it from the urine when the antidiuretic hormone is secreted. If there is more antidiuretic hormone present then there is less water excreted from the body which in turn causes an increase in total blood volume. What are two disorders that can affect our total blood volume?

Anatomy homework help

According to Mayo Clinic (2013), blood doping involves removing blood out of the body, storing it, and then reinfusing it to increase the number of red blood cells. As such, the athlete’s performance rises when the increased red blood cells are able to deliver more oxygen to the body tissues. Therefore, some athletes like Lance Armstrong have undergone blood doping just before a race to achieve improved performance.

I do not think the sporting world should legalize blood doping. Enhancing performance using an unnatural technique is cheating. Research has found out that in endurance sports, performance can increase by 10 percent when individuals use blood doping (Solheim et al., 2019). As a result, an athlete that undergoes blood doping will have a competitive advantage of other competitors. Specifically, blood doping prevents a level playing field when only some athletes use the method. Faiss et al. (2020) pointed out that blood doping leads to competitive advantage since it enhances performance; hence, some nations might benefit unfairly from the technique. For instance, if a country has more athletes using blood doping than other nations do, it has a higher probability of winning more medals.

Moreover, blood doping might present some health risks to the sportspeople. Blood doping is associated with physiological side effects such as blood clot, stroke, and higher stress on the heart (USADA, 2022). In addition, since blood doping involves removing, storing, and reinfusion of blood, the athletes are at risk of infections such as hepatitis and AIDs (Bird et al., 2016). Besides, mismatch of blood might occur if the professionals conducting the process are negligent.

References

Bird, S.R., Goebel, C., Burke, L.M., & Greaves, R.F. (2016). Doping in sport and exercise: Anabolic, ergogenic, health and clinical issues. Annals of Clinical Biochemistry, 53(2),196-221. https://doi.org/10.1177/0004563215609952 (Links to an external site.)

Faiss, R., Saugy, J., Zollinger, A., Robinson, N., Schuetz, F., Saugy, M., & Garnier, P. Y. (2020). Prevalence estimate of blood doping in elite track and field athletes during two major international events. Frontiers in Physiology, 11, 160. https://doi.org/10.3389/fphys.2020.00160 (Links to an external site.)

Mayo Clinic. (2013, June 13). Blood doping – Mayo Clinic [Video]. YouTube.https://www.youtube.com/watch?v=G7KZxIR1t-o (Links to an external site.)

Solheim, S. A., Bejder, J., Breenfeldt Andersen, A., Mørkeberg, J., & Nordsborg, N. B. (2019). Autologous blood transfusion enhances exercise performance-strength of the evidence and physiological mechanisms. Sports Medicine – Open, 5(1), 30. https://doi.org/10.1186/s40798-019-0204-1 (Links to an external site.)

USADA. (2022). Effects of performance-enhancing drugs. https://www.usada.org/athletes/substances/effects-of-performance-enhancing-drugs/ (Links to an external site.)

from
M1D1: Cheating to be Famous

May 5, 2022 4:35PM

MELISSA WHITING

PART B

Question 1:

Sickle cell disease affects millions of people world-wide, especially in sub-Saharan Africa (Campbell et al., 2021). Sickle cell anemia is one of the genetic blood disorders. It involves having defective hemoglobin and distorted red blood cells that do not go through blood vessels smoothly. Some people have sickle cell trait, which is a condition where an individual has one defective gene (Pecker & Naik, 2018). Studies are constantly reporting regarding the lack of knowledge of the genetic inheritance of the sickle cell trait pattern (Mayo-Gamble et al., 2019). Compared to other races, blacks are the most affected by sickle cell anemia. For instance, the chapter readings indicated that in about 500 African-Americans, one of them has sickle cell anemia in the United States. Therefore, sickle cell trait is also more common among African-Americans.

My question: Should healthcare professionals encourage all African-Americans to undergo testing for sickle cell trait to prevent sickle cell anemia?

References

Campbell, A. D., Colombatti, R., Andemariam, B., Strunk, C., Tartaglione, I., Piccone, C. M., Manwani, D., Asare, E. V., Boruchov, D., Farooq, F., Urbonya, R., Boatemaa, G. D., Perrotta, S., Sainati, L., Rivers, A., Rao, S., Zempsky, W., Sey, F., Segbefia, C., Inusa, B., … Antwi-Boasiako, C. (2021). An analysis of racial and ethnic backgrounds within the CASiRe International Cohort of Sickle Cell Disease Patients: Implications for disease phenotype and clinical research. Journal of Racial and Ethnic Health Disparities, 8(1), 99–106. https://doi.org/10.1007/s40615-020-00762-2 (Links to an external site.)

Mayo-Gamble, T. L., Schlundt, D., Cunningham-Erves, J., Murry, V. M., Bonnet, K., Quasie-Woode, D., & Mouton, C. P. (2019). Sickle cell carriers’ unmet information needs: Beyond knowing trait status. Journal of Genetic Counseling, 28(4), 812–821. https://doi.org/10.1002/jgc4.1124 (Links to an external site.)

Pecker, L. H., & Naik, R. P. (2018). The current state of sickle cell trait: Implications for reproductive and genetic counseling. Blood, 132(22), 2331–2338. https://doi.org/10.1182/blood-2018-06-848705 (Links to an external site.)

from
M1D1: Cheating to be Famous

May 5, 2022 5:31PM

MELISSA WHITING

Part B

CLASSMATE QUESTION #2:

The health condition that results in the most deaths and morbidity annually in the US is cardiovascular disease (Giannini et al., 2022). Most people are not aware of their coronary disease risk until they get a diagnosis. For that reason, a large number of patients die from the disease or become disabled. However, with the numbers in deaths from CHD decreasing, patients will need assistance and encouragement to manage their symptoms and reduce the chances of complications in the future (Anderson et al., 2016). Many methods and procedures are being recommended in the treatment of coronary heart disease (Galper et al., 2015).

Classmate question: How can healthcare professionals prevent coronary disease among their patients?

References

Anderson, L., Thompson, D. R., Oldridge, N., Zwisler, A., Rees, K., Martin, N., Taylor, R. S.& Taylor, R. S. (2016). Exercise‐based cardiac rehabilitation for coronary heart disease. Cochrane Database of Systematic Reviews, 2018(1), CD001800- CD001800. https://doi.org/10.1002/14651858.CD001800.pub3 (Links to an external site.)

Galper, B. Z., Wang, Y. C., & Einstein, A. J. (2015). Strategies for primary prevention of coronary heart disease based on risk stratification by the ACC/AHA lipid guidelines, ATP III guidelines, coronary calcium scoring, and C-reactive protein, and a global treat-all strategy: A comparative-effectiveness modeling study. PloS One, 10(9), e0138092. https://doi.org/10.1371/journal.pone.0138092 (Links to an external site.)

from
M1D1: Cheating to be Famous

May 7, 2022 7:42PM

MELISSA WHITING

PART C

CLASSMATE RESPONSE #1

Original Question

In chapter 13, we read about the cardiovascular system. One thing in particular that we read about was blood pressure, which is the force the heart pumps blood through the body. We also read about what hypertension is, which is the blood pressure being too high (Patton & Thibodeau, p. 296-397). In my nursing career, I have come across several different medications that help to reduce blood pressure, including diuretics which we also read about. Diuretics make the body urinate in order to decrease the amount of blood in the body which in turn helps the blood pressure decrease (Patton & Thibodeau, p.298). There are several different types of diuretics; for example, Furosemide (Lasix) is a loop-diuretic (Krakoff, 2005). Can you name other types of diuretics and how they work in the body?


My Response:

There are typically five classes of diuretics: thiazides, loop diuretics, carbon anhydrase inhibitors, potassium sparing and osmotic diuretics. Chlorothiazide is a diuretic often used to treat bronchopulmonary dysplasia in pediatric patients. It helps to improve lung mechanics by decreasing the edema that builds up in the lungs (VanderVeen, 2020). Diuretics also work when used in combinations for a better effect. For instance, there was a case study with a four-month-old baby with NDI (nephrogenic diabetes insipidus) who was given HCTZ (hydrochlorothiazide) which inhibits sodium reabsorption which can cause hypokalemia. Therefore, it will be given in conjunction with amiloride, a potassium sparing diuretic (Leung, et al., 2016). Lastly, Lasix has many uses, however, the most interesting to date that I have read about is a 32-year-old patient case study. The Lasix was used to reduce the pressure inside his inner ear as he was presenting with hearing loss (Kosec et al., 2019). In conclusion, diuretics have many uses and can be used individually or in combination with one another.

References

Košec, A., Kruljac, I., & Ajduk, J. (2019). Remission of Recurrent Cochlear Hydrops Associated With Bromocriptine Treatment for Macroprolactinoma. American Journal of Audiology, 28(3), 548–552. https://doi-org.ezproxy.indstate.edu/10.1044/2019_AJA-18-0191

Leung, T., Babbitt, C., & O, B. K. (2016). Severe Hypernatremia and Failure to Thrive. Clinical Pediatrics, 55(11), 1085–1087. https://doi-org.ezproxy.indstate.edu/10.1177/0009922816664069

VanderVeen, S. K. (2020). The Transition from Hospital to Home for a Patient with Bronchopulmonary Dysplasia: A Multidisciplinary Approach. Pediatric Nursing, 46(4), 184–188.

from
M1D1: Cheating to be Famous

May 7, 2022 8:05PM

MELISSA WHITING

Part C

CLASSMATE RESPONSE #2

Original Question:

According to Essentials of Anatomy and physiology Chapter 16, Blood is a liquid connective tissue consisting not only of fluid plasma but also of cells. Blood consist about 55% plasma, 45% of a variety of formed elements, Including Erythrocytes, thrombocytes and leukocytes.

What is the hematocrit and what is a disease marked by a decrease in the average hematocrit?


My Response:

Hematocrit is the ratio of the volume of red blood cells to the total volume of blood and can be measured by an instrument known as a centrifugation (Khongphatthanayothin et al., 2008). A disease marked by low hematocrit is leukemia (Bolin et al., 2020). Leukemia is a cancer of the bone marrow which is responsible for forming red blood cells. Individuals with leukemia form an overabundance of immature white blood cells, stopping them from forming other cells in the meantime. These individuals now become immunocompromised as well (Day et al., 2021).

References

Bolin, C., & Maricle, D. E. (2020). Leukemia: What School Psychologists Should Know. Communique (0164775X), 49(4), 10–13.

Day, M., Harris, S., Hussein, D., Saka, M. Y., Stride, C., Jones, M., Makin, G., & Rowe, R. (2021). The efficacy of interactive group psychoeducation for children with leukaemia: A randomised controlled trial. Patient Education & Counseling, 104(12), 3008–3015. https://doi-org.ezproxy.indstate.edu/10.1016/j.pec.2021.04.015

Khongphatthanayothin, A., Supachokechaiwattana, P., & Pantcharoen, C. (2008). Prediction of Capillary Leakage in Patients with Dengue Virus Infection: What Else Besides Hematocrit and Platelet Counts? Pediatrics, 121, S99. https://doi- (Links to an external site.) org.ezproxy.indstate.edu/10.1542/peds.2007-2022Z

Anatomy homework help

Prior to beginning work on this assignment, read Chapters 5, 6, 7, and 10 assigned this week. Also, review Chapters 1 through 4 from your Week 1 readings.

Completing this written assignment in Week 2 will assist you in writing your final paper titled Entering a Foreign Market Through Exports, which is due during Week 5 of this course. This rough draft that you create in Week 2 will become a substantial part of your Final Paper. Make sure to incorporate your instructor’s feedback received on your Week 2 paper when you work on your final paper in Week 5.

The goal of this paper is to identify a new country for export of high-tech equipment manufactured by an American company and formulate a successful global supply chain management strategy. While working on this Week 2 assignment, please consider the following scenario:

High-Tech Tools, Inc. is a company based in Otay Mesa, California. Among other high-tech equipment, the company specializes in manufacturing of the hand-held radar speed gun, a device used to measure the speed of moving objects. The radar speed gun is mostly utilized in law enforcement to measure the speed of moving vehicles. It is also often used in professional sport for measuring bowling speeds in cricket, speed of pitched baseballs, and speed of tennis serves. The company has seen a clear trend in the competition’s exportation of similar goods around the world. As the international logistics manager for this company, you have been asked by the chief executive officer (CEO) to help identify a foreign country where High-Tech Tools Inc.’s export sales of radar speed guns may become successful.

 

Using the readings assigned in Weeks 1 and 2 and additional research, write a proposal to High-Tech Tools, Inc.’s executive team. The proposal will advise the CEO of a potential export country based on the concepts learned and research conducted in the first two weeks of the class. Your proposal should start with a one-page executive summary (see the Writing Center’s 
Writing an Executive Summary (Links to an external site.)
) that provides a concise overview of the key points of your paper. The main points of your paper must address the following:

· Present an executive summary that identifies a new export country.

· Describe the benefits of exporting hi-tech equipment to the chosen country from the perspective of international trade theories and economic agreements.

· Explain any advantages or deficiencies in a transportation, communication, or utilities infrastructure in the selected country that may affect international logistics operations.

· Conclude your proposal with an informed decision regarding exporting to the chosen country based on your presented data.

 

The purpose of this assignment is to demonstrate an understanding of exporting as one of the entry modes into a foreign market and, thus, designing a successful global supply chain management strategy that executes the exporting plan. Critical thinking is required in order to differentiate between the benefits and challenges of exporting.

Submit your three- to four-page paper (not including the title and references pages) written according to 
APA Style (Links to an external site.)
 as shown in the approved style guide. Contextual (level one) headings must be used to organize your paper and your thoughts. The CEO has also asked you to include two scholarly and credible sources, in addition to the textbook, to support your ideas.

 

The Entering a Foreign Market Through Exports: A Rough Draft of Final Paper

· Must include a separate title page with the following:

· Title of paper in bold font

· Space should be between title and the rest of the information on the title page.

· Student’s name

· Name of institution (University)

· Course name and number

· Instructor’s name

· Due date

· Must utilize academic voice. See the 
Academic Voice (Links to an external site.)
 resource for additional guidance.

· Must start with a one-page executive summary and include a conclusion paragraph in the end of the paper that highlights the significance of your proposal.

· For assistance, see the Writing Center’s 
Introductions & Conclusions (Links to an external site.)
 as well as 
Writing an Executive Summary (Links to an external site.)
.

· Must use at least two scholarly and credible sources, in addition to the course text.

· The 
Scholarly, Peer-Reviewed, and Other Credible Sources (Links to an external site.)
 table offers additional guidance on appropriate source types. If you have questions about whether a specific source is appropriate for this assignment, please contact your instructor. Your instructor has the final say about the appropriateness of a specific source for your assignment.

· To assist you in completing the research required for this assignment, view this 
Quick and Easy Library Research (Links to an external site.)
 tutorial, which introduces the UAGC University Library and the research process, and provides some library search tips.

· Must document any information used from sources in APA Style as outlined in the Writing Center’s 
APA: Citing Within Your Paper (Links to an external site.)
 guide.

 

Carefully review the Grading Rubric (Links to an external site.)
 for the criteria that will be used to evaluate your assignment.

Anatomy homework help

Prior to beginning work on this assignment, read Chapters 5, 6, 7, and 10 assigned this week. Also, review Chapters 1 through 4 from your Week 1 readings.

Completing this written assignment in Week 2 will assist you in writing your final paper titled Entering a Foreign Market Through Exports, which is due during Week 5 of this course. This rough draft that you create in Week 2 will become a substantial part of your Final Paper. Make sure to incorporate your instructor’s feedback received on your Week 2 paper when you work on your final paper in Week 5.

The goal of this paper is to identify a new country for export of high-tech equipment manufactured by an American company and formulate a successful global supply chain management strategy. While working on this Week 2 assignment, please consider the following scenario:

High-Tech Tools, Inc. is a company based in Otay Mesa, California. Among other high-tech equipment, the company specializes in manufacturing of the hand-held radar speed gun, a device used to measure the speed of moving objects. The radar speed gun is mostly utilized in law enforcement to measure the speed of moving vehicles. It is also often used in professional sport for measuring bowling speeds in cricket, speed of pitched baseballs, and speed of tennis serves. The company has seen a clear trend in the competition’s exportation of similar goods around the world. As the international logistics manager for this company, you have been asked by the chief executive officer (CEO) to help identify a foreign country where High-Tech Tools Inc.’s export sales of radar speed guns may become successful.

 

Using the readings assigned in Weeks 1 and 2 and additional research, write a proposal to High-Tech Tools, Inc.’s executive team. The proposal will advise the CEO of a potential export country based on the concepts learned and research conducted in the first two weeks of the class. Your proposal should start with a one-page executive summary (see the Writing Center’s 
Writing an Executive Summary (Links to an external site.)
) that provides a concise overview of the key points of your paper. The main points of your paper must address the following:

· Present an executive summary that identifies a new export country.

· Describe the benefits of exporting hi-tech equipment to the chosen country from the perspective of international trade theories and economic agreements.

· Explain any advantages or deficiencies in a transportation, communication, or utilities infrastructure in the selected country that may affect international logistics operations.

· Conclude your proposal with an informed decision regarding exporting to the chosen country based on your presented data.

 

The purpose of this assignment is to demonstrate an understanding of exporting as one of the entry modes into a foreign market and, thus, designing a successful global supply chain management strategy that executes the exporting plan. Critical thinking is required in order to differentiate between the benefits and challenges of exporting.

Submit your three- to four-page paper (not including the title and references pages) written according to 
APA Style (Links to an external site.)
 as shown in the approved style guide. Contextual (level one) headings must be used to organize your paper and your thoughts. The CEO has also asked you to include two scholarly and credible sources, in addition to the textbook, to support your ideas.

 

The Entering a Foreign Market Through Exports: A Rough Draft of Final Paper

· Must include a separate title page with the following:

· Title of paper in bold font

· Space should be between title and the rest of the information on the title page.

· Student’s name

· Name of institution (University)

· Course name and number

· Instructor’s name

· Due date

· Must utilize academic voice. See the 
Academic Voice (Links to an external site.)
 resource for additional guidance.

· Must start with a one-page executive summary and include a conclusion paragraph in the end of the paper that highlights the significance of your proposal.

· For assistance, see the Writing Center’s 
Introductions & Conclusions (Links to an external site.)
 as well as 
Writing an Executive Summary (Links to an external site.)
.

· Must use at least two scholarly and credible sources, in addition to the course text.

· The 
Scholarly, Peer-Reviewed, and Other Credible Sources (Links to an external site.)
 table offers additional guidance on appropriate source types. If you have questions about whether a specific source is appropriate for this assignment, please contact your instructor. Your instructor has the final say about the appropriateness of a specific source for your assignment.

· To assist you in completing the research required for this assignment, view this 
Quick and Easy Library Research (Links to an external site.)
 tutorial, which introduces the UAGC University Library and the research process, and provides some library search tips.

· Must document any information used from sources in APA Style as outlined in the Writing Center’s 
APA: Citing Within Your Paper (Links to an external site.)
 guide.

 

Carefully review the Grading Rubric (Links to an external site.)
 for the criteria that will be used to evaluate your assignment.

Anatomy homework help

1

2

Facebook Website

Adriana C. Hernandez

Rasmussen University

COURSE#: MA242/BSC2087C

Jenessa Gerling

05/01/2022

Thesis Statement: Facebook, which emerged as a standalone website, is used worldwide. Facebook has emerged as one of the 21st century’s largest companies, with a consumer base of people who understand the word internet.

Title of Paper: Facebook Website

I. Introduction

A. Attention grabbing sentence about topic

Facebook, which emerged as a standalone website, is used worldwide. Skyrocketing revenues’ simplified version of the term perception is a way of perceiving or viewing things and refers to how the brain knows how things are or processes things (Mosquera et al.,2020).

B. Thesis statement

Facebook, which emerged as a standalone website, is used worldwide. Facebook has emerged as one of the 21st century’s largest companies, with a consumer base of people who understand the word internet.

II. First paragraph main point – topic sentence

The case in this study involves deciphering the website perception elements and related responses to the same crucial points as follows:

A. Supporting details (in-text citation for outside resource used as support/evidence)

1. Details about the supporting details

Sensory response refers to the way we respond to specific website visual elements. The website contains both a design pattern and a logo which most individuals worldwide are aware of today.

2. Details about the supporting details

The image of the logo is a letter f-like. The most dominant colour in the ad on Facebook is blue and white shades used to design and highlight the tangible symbol.

B. Supporting details (in-text citation)

There are also lines and shapes in the logo, and as mentioned, the logo lines include lines and a square box forming a bold character, ‘f’ and highlighting the Facebook company name (Plantin et al.,2018). Contrast and balance are also incorporated. There is contrast present and light colours in the image that easily distinguish the Facebook symbol from other symbols such as WhatsApp and YouTube. The balance is indicated in the proper depiction of the ‘F’ symbol, highlighting everything around the same.

C. Transition sentence

On the other hand, perceptual response refers to the number of groups of persons attracted to the ad and those not attracted.

III. Second paragraph main point – topic sentence

Though perceptual response targets a potential user base involving many people from any age group, ethnicity, or age, it is more dominant among the youth, in my view.

A. Supporting details (in-text citation)

The aged have no more time in the Facebook like the youth who are in desire remain informed and have interest in sharing their feelings and information through the platform (Plantin et al.,2018).

1. Details about the supporting details

The technical response involves specific elements, including buttons and dropdowns worldwide, which technically impact the user.

2. Details about the supporting details

This also applies to the user experience or interference that the user gets through the website’s usage (Kim & Yang,2017).

B. Supporting details (in-text citation)

Additionally, emotional response refers to the ease with which Facebook enables individuals to connect across the globe using its search techniques and how individuals can look for assorted topics, including politics and world events or even ordering for pizza or reach for consumers (Plantin et al.,2018).

C. Transition sentence

The also ethical response also is used and shows that Facebook has emerged as one of the most misused websites in the world.

IV. Third paragraph main point – topic sentence

Ethical response indicates that Facebook has no restriction on the type of information that is posted.

A. Supporting details (in-text citation)

It allows posting of information without consideration or limitation of the information that could derail society from its morals (Chugh &Ruhi,2018).

1. Details about the supporting details

There is no specified code of ethics in the use and utilization of this platform to pass information. It does not provide regulation on the terms to be used.

2. Details about the supporting details

Facebook has created the need for uploading better images than each other hence forming a false representation (Mosquera et al.,2020).

B. Supporting details (in-text citation)

has emerged as the website misused in spreading topics and information such as images that have people who are depressed and the fake news (Chugh &Ruhi,2018).

C. Transition sentence

Therefore, fakebook’s logo, ease of use, and accessibility has affected people’s perception over the type of users it has, how it emotionally affects its users, and how it is ad and app appear which has in turn made known by many people globally.

V. Conclusion

A. Summary of main points/Restatement of thesis statement

Facebook has emerged as the standalone website and is used globally and one among the world’s largest website as it is easy to use for all the people who understand how to use internet. This platform has less research towards members that are aged and towards the youth, respectively, and involvement is more centric.

B. Sentence to state a judgment on topic, make a prediction, or call the reader to action

Although the Facebook website’s ease of use has attracted many people across the globe and enhanced communication on global matters, but the platform needs to produce restriction on nature of information posted so as to ensure that it instills moral values to the young people.

References

Chugh, R., & Ruhi, U. (2018). Social media in higher education: A literature review of Facebook. Education and Information Technologies, 23(2), 605-616.

Kim, C., & Yang, S. U. (2017). Like, comment, and share on Facebook: How each behaviour differs from the other. Public relations review, 43(2), 441-449.

Mosquera, R., Odunowo, M., McNamara, T., Guo, X., & Petrie, R. (2020). The economic effects of Facebook. Experimental Economics, 23(2), 575-602.

Plantin, J. C., Lagoze, C., Edwards, P. N., & Sandvig, C. (2018). Infrastructure studies meet platform studies in the age of Google and Facebook. New media & society, 20(1), 293-310.

Anatomy homework help

1. Prepare a written paper of at least 1000 words discussing the following bullet points:

A. Describe anatomical and physiological changes that occur at the gross and histological levels during pregnancy and postpartum in the mother and developing human during the following stages:

-Fertilization

-Embryonic development

-Fetal development

-Birth

-Postpartum period

B. Examine how hormones regulate the ovarian cycle, in utero development, and the process of labor and giving birth.

C. Briefly discuss the similarities and differences in oogenesis vs. Spermatogenesis.

2. Your paper should be formatted as a proper research paper with an introduction and conclusion. Do not simply follow the bullet points above, but really think about what you have learned and how that relates to other material we have covered, and knowledge you have from other courses you may have taken. All references must be cited using APA Style format.

Anatomy homework help

1

2

Facebook Website

Adriana C. Hernandez

Rasmussen University

COURSE#: MA242/BSC2087C

Jenessa Gerling

05/01/2022

Thesis Statement: Facebook, which emerged as a standalone website, is used worldwide. Facebook has emerged as one of the 21st century’s largest companies, with a consumer base of people who understand the word internet.

Title of Paper: Facebook Website

I. Introduction

A. Attention grabbing sentence about topic

Facebook, which emerged as a standalone website, is used worldwide. Skyrocketing revenues’ simplified version of the term perception is a way of perceiving or viewing things and refers to how the brain knows how things are or processes things (Mosquera et al.,2020).

B. Thesis statement

Facebook, which emerged as a standalone website, is used worldwide. Facebook has emerged as one of the 21st century’s largest companies, with a consumer base of people who understand the word internet.

II. First paragraph main point – topic sentence

The case in this study involves deciphering the website perception elements and related responses to the same crucial points as follows:

A. Supporting details (in-text citation for outside resource used as support/evidence)

1. Details about the supporting details

Sensory response refers to the way we respond to specific website visual elements. The website contains both a design pattern and a logo which most individuals worldwide are aware of today.

2. Details about the supporting details

The image of the logo is a letter f-like. The most dominant colour in the ad on Facebook is blue and white shades used to design and highlight the tangible symbol.

B. Supporting details (in-text citation)

There are also lines and shapes in the logo, and as mentioned, the logo lines include lines and a square box forming a bold character, ‘f’ and highlighting the Facebook company name (Plantin et al.,2018). Contrast and balance are also incorporated. There is contrast present and light colours in the image that easily distinguish the Facebook symbol from other symbols such as WhatsApp and YouTube. The balance is indicated in the proper depiction of the ‘F’ symbol, highlighting everything around the same.

C. Transition sentence

On the other hand, perceptual response refers to the number of groups of persons attracted to the ad and those not attracted.

III. Second paragraph main point – topic sentence

Though perceptual response targets a potential user base involving many people from any age group, ethnicity, or age, it is more dominant among the youth, in my view.

A. Supporting details (in-text citation)

The aged have no more time in the Facebook like the youth who are in desire remain informed and have interest in sharing their feelings and information through the platform (Plantin et al.,2018).

1. Details about the supporting details

The technical response involves specific elements, including buttons and dropdowns worldwide, which technically impact the user.

2. Details about the supporting details

This also applies to the user experience or interference that the user gets through the website’s usage (Kim & Yang,2017).

B. Supporting details (in-text citation)

Additionally, emotional response refers to the ease with which Facebook enables individuals to connect across the globe using its search techniques and how individuals can look for assorted topics, including politics and world events or even ordering for pizza or reach for consumers (Plantin et al.,2018).

C. Transition sentence

The also ethical response also is used and shows that Facebook has emerged as one of the most misused websites in the world.

IV. Third paragraph main point – topic sentence

Ethical response indicates that Facebook has no restriction on the type of information that is posted.

A. Supporting details (in-text citation)

It allows posting of information without consideration or limitation of the information that could derail society from its morals (Chugh &Ruhi,2018).

1. Details about the supporting details

There is no specified code of ethics in the use and utilization of this platform to pass information. It does not provide regulation on the terms to be used.

2. Details about the supporting details

Facebook has created the need for uploading better images than each other hence forming a false representation (Mosquera et al.,2020).

B. Supporting details (in-text citation)

has emerged as the website misused in spreading topics and information such as images that have people who are depressed and the fake news (Chugh &Ruhi,2018).

C. Transition sentence

Therefore, fakebook’s logo, ease of use, and accessibility has affected people’s perception over the type of users it has, how it emotionally affects its users, and how it is ad and app appear which has in turn made known by many people globally.

V. Conclusion

A. Summary of main points/Restatement of thesis statement

Facebook has emerged as the standalone website and is used globally and one among the world’s largest website as it is easy to use for all the people who understand how to use internet. This platform has less research towards members that are aged and towards the youth, respectively, and involvement is more centric.

B. Sentence to state a judgment on topic, make a prediction, or call the reader to action

Although the Facebook website’s ease of use has attracted many people across the globe and enhanced communication on global matters, but the platform needs to produce restriction on nature of information posted so as to ensure that it instills moral values to the young people.

References

Chugh, R., & Ruhi, U. (2018). Social media in higher education: A literature review of Facebook. Education and Information Technologies, 23(2), 605-616.

Kim, C., & Yang, S. U. (2017). Like, comment, and share on Facebook: How each behaviour differs from the other. Public relations review, 43(2), 441-449.

Mosquera, R., Odunowo, M., McNamara, T., Guo, X., & Petrie, R. (2020). The economic effects of Facebook. Experimental Economics, 23(2), 575-602.

Plantin, J. C., Lagoze, C., Edwards, P. N., & Sandvig, C. (2018). Infrastructure studies meet platform studies in the age of Google and Facebook. New media & society, 20(1), 293-310.

Anatomy homework help


Endocrine System Anatomy

This sheet is designed to help you learn about the Anatomy Endocrine System. Several endocrine organs have been labelled A- J. When asked a question about an organ, be sure to name the organ before answering the question.

Answers are to be written in blue

Q: Which one of the labeled organs produces testosterone?

A: A, Kidney

Diagram  Description automatically generated

1) Which one of the labeled organs produces testosterone?

2) Which one of labelled organs produces estrogen?

3) Which one of the labelled organs produces GnRH?

4) Which one of the labelled organs produces prolactin?

5) Which one of the labelled organs produces a hormone which is very important in metabolism regulation?

6) Which one of the labelled organs produces melatonin?

7) Which one the labelled organs produce luteinizing hormone and follicle stimulating hormone?

8) Which one of the labelled organs produces a hormone necessary for the regulation of urine production?

9) Which one of the labelled organs produces a hormone responsible for the implantation of a blastocyte in the uterus?

10) Which one of the labelled organs produces a hormone responsible for the production of red blood cells?

11) Which one of the labelled organs produces a hormone responsible for the production of a hormone called ANP?

12) Releasing factors are hormones usually produced by this labelled organ?

13) Which one of the labelled organs produces a hormone responsible for the production of a hormone necessary for the absorption of glucose?

Anatomy homework help

1. Prepare a written paper of at least 1000 words discussing the following bullet points:

A. Describe anatomical and physiological changes that occur at the gross and histological levels during pregnancy and postpartum in the mother and developing human during the following stages:

-Fertilization

-Embryonic development

-Fetal development

-Birth

-Postpartum period

B. Examine how hormones regulate the ovarian cycle, in utero development, and the process of labor and giving birth.

C. Briefly discuss the similarities and differences in oogenesis vs. Spermatogenesis.

2. Your paper should be formatted as a proper research paper with an introduction and conclusion. Do not simply follow the bullet points above, but really think about what you have learned and how that relates to other material we have covered, and knowledge you have from other courses you may have taken. All references must be cited using APA Style format.

Anatomy homework help

Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes

Anatomy homework help


Endocrine System Anatomy

This sheet is designed to help you learn about the Anatomy Endocrine System. Several endocrine organs have been labelled A- J. When asked a question about an organ, be sure to name the organ before answering the question.

Answers are to be written in blue

Q: Which one of the labeled organs produces testosterone?

A: A, Kidney

Diagram  Description automatically generated

1) Which one of the labeled organs produces testosterone?

2) Which one of labelled organs produces estrogen?

3) Which one of the labelled organs produces GnRH?

4) Which one of the labelled organs produces prolactin?

5) Which one of the labelled organs produces a hormone which is very important in metabolism regulation?

6) Which one of the labelled organs produces melatonin?

7) Which one the labelled organs produce luteinizing hormone and follicle stimulating hormone?

8) Which one of the labelled organs produces a hormone necessary for the regulation of urine production?

9) Which one of the labelled organs produces a hormone responsible for the implantation of a blastocyte in the uterus?

10) Which one of the labelled organs produces a hormone responsible for the production of red blood cells?

11) Which one of the labelled organs produces a hormone responsible for the production of a hormone called ANP?

12) Releasing factors are hormones usually produced by this labelled organ?

13) Which one of the labelled organs produces a hormone responsible for the production of a hormone necessary for the absorption of glucose?

Anatomy homework help

Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes
Alex Holmes

Anatomy homework help

Discussion – Empathetic Care

Initial Post

Choose one of the infectious respiratory disorders from this module to discuss the multidimensional care strategies for this disorder. List these interventions based on priority and include a rationale as to why you prioritized them in this manner.


TOPIC: Pulmonary Tuberculosis (TB)

Tuberculosis is an acute or chronic infection caused by the organism mycobacterium tuberculosis. Tuberculosis is one of the most common bacterial infections worldwide. Tuberculosis is an airborne disease. Patients with active TB can transmit the disease by coughing, sneezing, or whistling. Droplets are spread into the air and have the potential to infect others.

Risk Factors for TB

· contacts with someone with TB

· Drug and alcohol abuse

· Immunosuppression

· Multiple sex partners

· Co-habiting in a shelter

· Homeless

Recent travel

References:

Anatomy homework help

Discussion – Empathetic Care

Initial Post

Choose one of the infectious respiratory disorders from this module to discuss the multidimensional care strategies for this disorder. List these interventions based on priority and include a rationale as to why you prioritized them in this manner.


TOPIC: Pulmonary Tuberculosis (TB)

Tuberculosis is an acute or chronic infection caused by the organism mycobacterium tuberculosis. Tuberculosis is one of the most common bacterial infections worldwide. Tuberculosis is an airborne disease. Patients with active TB can transmit the disease by coughing, sneezing, or whistling. Droplets are spread into the air and have the potential to infect others.

Risk Factors for TB

· contacts with someone with TB

· Drug and alcohol abuse

· Immunosuppression

· Multiple sex partners

· Co-habiting in a shelter

· Homeless

Recent travel

References: