Human Anatomy 7th Edition Marieb Wilhelm Mallatt Instructors Manual
Human Anatomy 7th Edition Marieb Wilhelm Mallatt Instructors Manual
Human Anatomy 7th Edition Marieb Wilhelm Mallatt Instructors Manual
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Lecture and Demonstration
PART ONE: GENERAL CHARACTERISTICS OF BLOOD VESSELS
- Describe the three tunics that form the wall of an artery or vein.
- Define vasa vasorum.
- Compare and contrast the structure and functions of elastic arteries, muscular arteries, and arterioles.
- Describe the structure and function of capillaries, sinusoids, and capillary beds, and
explain the structural basis of capillary permeability.
- Explain how to distinguish a vein from an artery in histological sections.
- Describe the structural features of arteries and veins that help maintain the flow of blood through these vessels.
- Define vascular anastomoses and explain their functions.
PART TWO: BLOOD VESSELS OF THE BODY
- Define pulmonary and systemic circuits.
- Name the major vessels of the pulmonary circuit.
- Name the three vessels that arise from the aortic arch. Describe the routes of arterial blood supply from these vessels to the head and neck, the brain, the thorax, and the upper limb.
- Describe the pathways and the organs supplied by the midline arteries and by the paired arteries branching off the abdominal aorta.
- Describe the pathway of arterial supply to the pelvis and the lower limb.
- Identify the location of pulse points in the limbs, head, and neck.
- Trace the veins that empty into the superior vena cava as you describe the routes of
venous return from the brain, the head and neck, and the thorax and upper limbs.
- Trace the veins that empty into the inferior vena cava as you trace venous return from the abdominal organs and from the pelvis and lower limbs.
- Describe the structure and specific function of the hepatic portal system, and explain the significance of portal-systemic anastomoses.
- Define atherosclerosis, deep vein thrombosis, venous disease of the lower limb,
aneurysm, microangiopathy of diabetes, and arteriovenous malformation.
- Trace the cardiovascular circuit in the fetus, and explain how it changes at birth.
- List some effects of aging on the blood vessels.
Suggested Lecture Outline
PART ONE: GENERAL CHARACTERISTICS OF BLOOD VESSELS (PP. 589–596,
The main types of blood vessels are arteries, capillaries, and veins. Arteries carry blood
away from the heart and toward the capillaries; veins carry blood away from the capillaries and toward the heart. Arteries “branch,” whereas veins “serve as tributaries.”
- Structure of Blood Vessel Walls (p. 589)
- Except for capillaries, blood vessel walls have three tunics: tunica intima, tunica media, and tunica externa; tunica media is thicker in arteries than in veins.
- Vasa vasorum are small arteries, capillaries, and veins that serve walls of larger vessels, such as the aorta. (p. 589, Fig. 20.2a)
- Types of Blood Vessels (pp. 589–595, Figs. 20.1–20.6, Table 20.1)
- The passage of blood through arteries proceeds from elastic arteries (the largest) to
muscular arteries (middle-sized, distributing arteries), to arterioles (the smallest).
(pp. 589–592, Figs. 20.1, 20.2, Table 20.1)
- Capillaries are the smallest blood vessels. They have a diameter of 8–10 µm, just large enough to permit the passage of erythrocytes in single file; the wall is a single layer of endothelium. (pp. 592–593, Figs. 20.1 and 20.3–20.5, Table 20.1)
- Sinusoids are wide, leaky capillaries that occur in bone marrow, spleen, and liver
tissues. (p. 593, Fig. 20.5c)
- Capillary permeability permits the exchange of nutrients and wastes between blood and tissue fluid; four routes of capillary permeability allow molecules to pass into and out of capillaries. (p. 593)
- The blood brain barrier is an example of low-permeability capillaries; all but the most vital molecules are prevented from leaving the blood and entering the brain tissue.
(p. 593, Fig. 20.5a)
- A capillary bed is a network of the body’s smallest vessels; beds run through almost all tissues, especially loose connective tissues. (p. 593)
- Sometimes blood is shunted straight through a capillary bed (from arteriole to metarteriole to thoroughfare channel to venule) and does not enter the true capillaries surrounding the tissue. (p. 593, Fig. 20.4)
- Veins are formed from the smallest veins called venules; the smallest venules are
postcapillary venules. (pp. 594–595, Fig. 20.1)
- Venous blood is under less pressure than arterial blood; compared to arteries, veins have thinner walls, a wider lumen, a thinner tunica media, a thicker tunic externa, and valves. (p. 595, Fig. 20.6)
III. Vascular Anastomoses (pp. 595–596)
- Vascular anastomoses occur where vessels unite or interconnect; arterial anastomoses serve a common organ, such as the brain or a joint; venous anastomoses are much more common than anastomoses between arteries. (p. 595)
PART TWO: BLOOD VESSELS OF THE BODY (pp. 596–623, Figs. 20.7–20.25)
There are several important patterns of circulation; the two basic patterns are pulmonary
circulation and systemic circulation; other examples are myocardial circulation and hepatic portal circulation.
- The Pulmonary Circulation (pp. 596–597, Fig. 20.7)
- Oxygen-poor blood leaves the heart, and oxygen-rich blood returns to the heart via the following vessels: pulmonary trunk, pulmonary arteries, lobar arteries, lung capillaries, and pulmonary veins.
- The Systemic Circulation (pp. 597–618, Figs. 20.8–20.22)
- Not all vessels on the right and left sides of the body are mirror images. (p. 597)
- Systemic arteries carry oxygenated blood from the heart to the capillaries of organs throughout the body. (p. 597, Fig. 20.8)
- The aorta is the largest artery in the body; three parts of the aorta are the ascending aorta, the aortic arch, and the descending aorta. (p. 599, Figs. 20.8, 20.9)
- Arteries that supply the head and neck are the single brachiocephalic and paired common carotids, internal and external carotids, and vertebrals; the neck is also supplied by the thryocervical and costocervical trunks. (pp. 600–601, Fig. 20.10)
- Arteries that supply the thoracic wall are the internal thoracic and intercostal arteries; thoracic visceral organs are supplied by branches of the thoracic aorta. (pp. 602–603,
- The upper limbs are supplied by arteries that arise from the subclavian arteries: axillary, brachial, radial, ulnar, and palmar arch. (p. 603, Fig. 20.11)
- Arterial supply to the abdomen arises from the abdominal aorta; abdominal arteries
include the inferior phrenics, the unpaired celiac trunk that branches into the left gastric, splenic, and common hepatic, the unpaired superior mesenteric, suprarenals, renals,
gonadals, the unpaired inferior mesenteric, lumbars, median sacral, and the common iliac arteries. (pp. 603–606, Figs. 20.12–20.14)
- The following arteries supply the pelvis and lower limbs: common iliac, internal iliac, femoral popliteal, anterior tibial, posterior tibial, and plantar arch. (pp. 606–608,
Figs. 20.14, 20.15)
- Systemic veins carry deoxygenated blood from the capillaries of organs throughout the body toward the heart; the superior and inferior venae cavae are the body’s main veins. (pp. 608 and 610, Fig. 20.16)
- The superior vena cava receives venous blood from all body regions superior to the
diaphragm, excluding the heart wall; the inferior vena cava receives venous blood from all body regions inferior to the diaphragm. (p. 610, Figs. 20.16)
- Most blood draining from the head and neck enter three pairs of veins: the internal jugulars, the external jugulars, and the vertebrals; the venous dural sinuses drain the brain and empty into the internal jugulars. (pp. 610–611, Figs. 20.17, 20.18)
- Veins of the thorax are the azygos, the hemiazygos, and the accessory hemiazygos.
(pp. 611–612, Fig. 20.19)
- Veins of the upper limb are deep or superficial; deep veins have companion names and locations of the upper limb arteries; superficial veins of the upper limb are the cephalic, median cubital, and basilic. (pp. 612–613, Figs. 20.19, 20.20)
- Most veins of the abdomen share companion names of the abdominal arteries and drain into the inferior vena cava: lumbar, gonadal, renal, suprarenal, and hepatic veins.
(pp. 613–616, Fig. 20.21)
- The hepatic portal system delivers nutrient-laden blood from the intestines to the liver; tributaries of the hepatic portal system are the superior mesenteric, splenic, inferior mesenteric, and portal vein. (pp. 613 and 616, Fig. 20.22)
- Portal-systemic anastomoses provide emergency pathways through which backup portal blood can return to the heart; overloads result in esophageal bleeding, hemorrhoids, and caput medusae. (p. 616)
- Deep veins of the pelvis and lower limb share the names of the arteries they accompany: plantar arch, posterior and anterior tibials, fibular, popliteal, femoral, external iliac, internal iliac, and common iliac veins; superficial veins are the great saphenous and small
saphenous veins. (pp. 616–617, Fig. 20.23)
III. Disorders of the Blood Vessels (pp. 618–619, Fig. 20.24)
- Examples of blood vessel disorders are atherosclerosis, aneurysm, deep vein thrombosis of the lower limbs, venous disease, microangiopathy of diabetes, and arteriovenous
- Blood Vessels Throughout Life (pp. 620–623, Fig. 20.25)
- Embryonic blood vessels form during week 3. (p. 623)
- All major fetal circulation vessels are in place by the third month. (p. 623)
- Unique fetal anatomical vessels and structures are the umbilical arteries, the single
umbilical vein, ductus venosus, foramen ovale, and the ductus arteriosus. (p. 623,
- Stress that arteries carry blood away from the heart and “branch” or “fork.” Stress that veins carry blood toward the heart and “join” or “serve” as tributaries.
- When describing blood vessel wall structure, emphasize the relationship of structure to function. The tunica interna reduces friction between the vessel walls and blood; the
tunica media controls vasoconstriction and vasodilation of the vessel; the tunica externa protects, reinforces, and anchors the vessel to the surrounding structures.
- Explain that arterioles, as the smallest arteries, regulate blood flow into capillary beds through vasoconstriction and vasodilation.
- Students find interesting the concept that the heart is “a big blood vessel.” Explain how the endocardium corresponds to the tunica intima, the myocardium corresponds to the
tunica media, and the connective tissue portion of the epicardium corresponds to the
- Explain that the degree of vascularity varies throughout the body; compare a highly
vascular part, such as the brain, with examples that are poorly vascular, such as ligaments and tendons, and avascular examples, such as the cornea and lens.
- When discussing circulatory pathways, emphasize the important differences between
arteries and veins: (1) there is one terminal systemic artery, the aorta, but two terminal systemic veins, the superior and inferior venae cavae; (2) arteries run deep and are well protected, but veins are both deep, which run parallel to the arteries, and superficial, which run just beneath the skin; (3) arterial pathways tend to be clear and distinct, but there are often many interconnections in venous pathways, making them difficult to
follow; and (4) there are at least two areas where venous drainage does not parallel the arterial supply: the venous dural sinuses draining the brain, and the hepatic portal system draining from the digestive organs to the liver before entering the main systemic
- Review the basics of pulmonary and systemic circulation before introducing the major blood vessels of the body.
- Incorporate schematic drawings to help students master the function of the cardiovascular system.
- Point out that vessels in the head and limbs are mostly bilaterally symmetrical, but some vessels on the right side and left side of the body are not always mirror images of each other, and some deep trunk vessels are asymmetrical.
- Explain how to “trace a drop of blood” from one location in the body to another, beginning and ending in capillaries.
Classroom Discussion Topics and Activities
- Display a model of a human torso, a model of the circulatory vessels, and/or a wall chart to exhibit the major blood vessels of the body. Point out major blood vessels and have students name them.
- Use a short piece of cloth-wrapped garden hose to show the layers (tunics) of arteries and veins. Wrap the hose with one color (red) to represent the tunica media and another color (white) to represent the tunica externa (adventitia).
- Use a short piece of soaker hose to illustrate a capillary as the “functional unit” of the circulatory system.
- Blow up a long balloon to imitate an aneurysm or a varicose vein.
- Direct the class in solving blood-tracing problems using a flowchart format. Assign
several blood-tracing problems, or allow students to make up their own. A few examples include tracing a drop of blood from the:
- brain to the kidney
- left foot to the right thumb
- small intestine to the posterior knee
- left testis to the spleen
- myocardium to the liver
- left thorax to the face
- placenta back to the placenta
- Discuss the significance of a healthy diet low in saturated fat in maintaining normal blood flow.
- Discuss why some coronary bypass surgeries have to be repeated after a few years.
- Discuss what occurs when an artery loses its elasticity.
- Ask students to think about answers to the following questions for a class discussion:
- What factors or events retard venous return?
- Why do water and dissolved solutes leave the bloodstream at the arteriole end of a capillary bed and enter the bloodstream at the venule end of the bed?
- Why is the elasticity of the large arteries so important? Or, why is arteriosclerosis such a threat? (Refer to “A Closer Look: Atherosclerosis? Get Out the Cardiovascular Drano,” p. 619)
- Project an unlabeled copy of Figures 20.8 and 20.16, and instruct students to name the vessels.
- Atherosclerosis is a stealthy killer. Describe the disease process, noting the involvement of specific cells and tissue types.
Answer: See “A Closer Look” on p. 619 of the and the articles on atherosclerosis in the Suggested Readings that follow.
- A woman in her early 50s showed up at the walk-in clinic complaining of an aching pain in her right leg following a fall. Visual examination revealed that the medial aspect of that leg was red and swollen. A diagnosis of phlebitis was made. What is phlebitis, and what more serious condition may follow if proper healing does not occur?
Answer: Phlebitis is an inflammation of a vein, accompanied by painful throbbing and redness of the skin over the inflamed vein. If proper healing does not occur, stagnant blood may clot within the vein (this is thrombophlebitis). The danger is that the clot could detach and form an embolus.
- The day after Spike returned from winning a boxing match, he heard that the boxer who lost suffered a ruptured middle meningeal artery from the knockout blow. Where is this artery located, and what are some likely consequences of its rupture?
Answer: The middle meningeal artery, a branch of the external carotid and maxillary
arteries, runs along the broad internal surfaces of the parietal bone and squamous-temporal bone of the cranium. A rupture of this artery is likely to cause a large hematoma, which exerts pressure on the underlying cerebral cortex of the brain, interfering with the conscious, cortical functions.
- One way that clinicians check patients for the advanced stages of alcoholism is to
look for the caput medusae and hemorrhoids. Explain why these may be symptoms of advanced alcoholism.
Answer: Both the superficial veins around the navel and the hemorrhoidal veins are
anastomoses between portal blood and systemic blood (see the discussion of portal-systemic anastomoses). Chronic alcoholics often have cirrhosis of the liver, which
obstructs the flow of portal blood through the liver sinusoids. This blood backs up and overfills the portal-systemic anastomoses around the navel (causing the Medusa head) and overfills the hemorrhoidal veins (causing hemorrhoids).
Transparencies Index/Instructor Resource DVD
Figure 20.1 Generalized structure of arteries, veins, and capillaries.
Figure 20.2 Comparison of arterial wall structure.
Figure 20.3 Red blood cells passing through a capillary.
Figure 20.4 Capillary structure.
Figure 20.5 Anatomy of a capillary bed.
Figure 20.6 Blood flow through veins.
Figure 20.7 Pulmonary circulation.
Figure 20.8 Major arteries of the systemic circulation.
Figure 20.9 The great vessels that exit and enter the heart.
Figure 20.10 Arteries of the head, neck, and brain.
Figure 20.11 Arteries of the thorax and right upper limb.
Figure 20.12 Major branches of the abdominal aorta.
Figure 20.13 Midline branches off the abdominal aorta supplying the organs of the
Figure 20.14 Arterial supply to the pelvis.
Figure 20.15 Arteries of the right pelvis and lower limb.
Figure 20.16 Major veins of the systemic circulation, anterior view.
Figure 20.17 Venous drainage of the head, neck, and brain.
Figure 20.18 Veins of the head and neck, right superficial aspect.
Figure 20.19 Veins of the thorax and right upper limb, anterior view.
Figure 20.20 The superficial veins of the right upper limb.
Figure 20.21 Tributaries of the inferior vena cava.
Figure 20.22 The hepatic portal system.
Figure 20.23 Veins of the right lower limb and pelvis.
Figure 20.24 Sixty-four-slice CT angiogram of an abdominal aortic aneurysm.
Figure 20.25 Fetal and newborn circulation.
Table 20.1 Summary of Blood Vessel Anatomy
A Closer Look Atherosclerosis? Get Out the Cardiovascular Drano.
Teaching with Art
Figure 20.25 Fetal and newborn circulation.
p. 620; transparencies; Instructor Resource DVD.
Checklist of Key Points in the Figure
- Explain that major vessels are in place by the embryonic third month and that blood flows in the same direction as the adult.
- Describe the placenta as the organ of transport between the fetus and the mother, functioning as the fetal respiratory organ.
- Explain that fetal lungs and liver receive very little blood; define shunt.
- Define umbilical cord, stressing there are two umbilical arteries and one umbilical vein.
- Describe the location and function of the ductus venosus, foramen ovale, and ductus
arteriosus; identify future adult derivatives.
Common Conceptual Difficulties Interpreting the Art
- Stress that an umbilical artery carries blood away from the fetal heart and that an umbilical vein carries blood to the fetal heart. It is the fetal heart that is the point of reference, not the maternal heart.
- Describe the mixing of oxygenated and deoxygenated blood.
- Explain why shunts away from pulmonary circulation are necessary in the fetal heart.
- Point out that the prenatal circulatory pattern must be able to rapidly convert to the
postnatal circulatory pattern.
Using Figure 20.25, instruct students to design a flowchart that traces a drop of blood from the placenta back to the placenta. Include all shunts and color code high, moderate, low, and very low regions of blood oxygenation.
Looking at Figure 20.25, ask students to identify the adult (“newborn”) structures derived from the following fetal structures and to describe their locations in the adult using additional figures from the :
- Umbilical vein
- Umbilical arteries
- Ductus venosus
- Foramen ovale
- Ductus arteriosus
- The ligamentum teres (“round ligament”), the remnant of the umbilical vein, is contained in the anterior margin of the falciform ligament of the liver. Refer to Figure 23.25.
- The umbilical arteries become the medial umbilical ligaments in the anterior abdominal wall inferior to the navel. Refer to Figure 20.25.
- The ligamentum venosum on the liver’s inferior surface is the fetal remnant of the ductus venosus. Refer to Figure 23.26.
- The fossa ovalis is the fetal remnant of the foramen ovale and appears as a depression in the interatrial septum. Refer to Figure 19.5e.
- Postnatally, the ductus arteriosus becomes the ligamentum arteriosum, a fibrous interconnection between the pulmonary trunk and aortic arch. Refer to Figure 19.5b.
Supplemental Course Materials
Library Research Topics
- Research the congenital defects of circulation that result from differences between the
fetal and adult circulations.
- Research the risk factors implicated in atherosclerosis and what can be done to minimize the risk.
- Research procedures and the types of valves currently used in valve replacement surgery.
- Research data from the past three years to the present concerning vascular health and components of a healthy diet.
- Research methods by which one can effectively lower LDL cholesterol, while raising HDL cholesterol.
See Appendix A of the Instructor Resource Guide for “Key to Audiovisual Distributors.”
- The Anatomy of Circulation (FHS; 50 min., 2005). Dr. Gunther von Hagens describes
the details and interactions of the circulatory and respiratory systems, dissects a heart, and studies the path of blood vessels to various organs. Dr. von Hagens also discusses specific respiratory and circulatory diseases. Of particular interest may be his discussions of arteriosclerosis and myocardial infarction.
- Circulation: What an Autopsy Reveals (FHS; 49 min., 2006). In this program, Dr. von Hagens joins pathologist Dr. John Lee to explore the blood vessels and heart of a woman who died of heart disease. By pumping a UV-sensitive compound into the dead woman’s blood vessels, they also illustrate how blockages affect circulation and damage internal organs.
- The Circulatory System (FHS; 22 min., 2009). This program is one section of the series The Human Body: How It Works. Topics presented in this video include the composition of blood, blood types, the role of hemoglobin, and factors affecting blood pressure.
- Coronary Artery Disease (FHS; 28 min., 2003). Coronary artery disease kills more
people each year than any other degenerative disease. This program looks at risk factors for CAD, including diet, lifestyle, and heredity. Several case studies describe how surviving a serious coronary event has changed their outlooks on their lives.
- Life Under Pressure (FHS; 26 min.). This program follows the journey of a red blood cell around the circulatory system to demonstrate the efficient and elegant design of
oxygen and food delivery to all parts of the body. It shows how veins and arteries are structured to perform their tasks.
- Massive Blood Loss: Circulatory System Emergencies (FHS; 48 min., 2008). Dr. Gunther von Hagens explains the consequences of serious blood loss, including hypoxia and
organ failure. He demonstrates knife wounds by stabbing a frozen human torso and then slicing the torso to show the tracks of the damage.
- Middle Years (FHS; 51 min., 2007). During the 4th to 5th decades of life, many imperfections in our anatomy start becoming evident. This program explores many of the
degenerative illnesses of the circulatory system, including aneurysm, heart disease, and the consequences of smoking cigarettes.
- Pumping Life—The Heart and Circulatory System (WNSE; 20 min.). This program
explains the structure and function of the heart, using animation and live action. It also discusses heart problems and the importance of preventive maintenance.
- William Harvey and the Circulation of Blood (FHS; 29 min.). This program provides an introduction to the life and work of William Harvey, the English physician and physiologist who discovered the circulation of blood in the human body in 1628. The program
describes the way in which Harvey formulated his revolutionary new theories of cardiac action and of the motion of the blood through the heart, arteries, and veins.
- Explorer: Cardiovascular System CD-ROM (WNSE; Win/Mac). This program illustrates the role the heart plays in the function of the human body. It investigates the heart as well as its function, the effect of drugs, cardiac fitness, and various heart disorders.
- Practice Anatomy Lab 3.0 (PAL) (BC; DVD, website) is a comprehensive program that students can access from www.myaandp.com or from the DVD. Students will find it beneficial to study the Cardiovascular System section of the Cadaver module and photomicrographs of blood vessels in the Histology module. Teachers will also find the PAL Instructor Resource DVD helpful for creating online quizzes.
Arampatzis, C. “Coronary Atherosclerosis: Current Management and Treatment.” 1st ed.,
Informa Healthcare, 2012.
Ballantyne, Christie. Dyslipidemia and Atherosclerosis Essentials. 4th ed., Jones & Bartlett Publsihers, 2008.
Foley, Natalia. Anatomy and Physiology of the Blood Vessels. Liberty Soldier, 2007.
Fuster, V., R. Walsh, and R. Harrington. Hurst’s the Heart. 13th ed., McGraw-Hill Professional, 2010.
George, Sarah Jane. Atherosclerosis. 1st edition., Wiley-VCH, 2010.
Hoffman-Kim, Diane. “Tissue Engineering: Heart valves.” Science and Medicine 8 (March/April 2002): 62–64.
Iaizzo, P. Handbook of Cardiac Anatomy, Physiology, and Devices. 2nd ed., Springer, 2009.
Moore, K. L. Clinically Oriented Anatomy. 6th ed. Philadelphia: Lippincott Williams &
Wick, Georg, and Cecilia Grundtman. Inflammation and Atherosclerosis. Springer, 2012.
Answers to Questions
Answers for multiple-choice and matching questions 1–16 are located in Appendix B of the
Short Answer and Essay Questions
- (a) There are four paths by which molecules pass into and out of capillaries: (1) through the clefts between the endothelial cells; (2) through the pores of fenestrated capillaries; (3) by diffusing directly through the endothelial cell membranes; and (4) through
cytoplasmic vesicles (caveolae) that invaginate from the plasma membrane and migrate across the endothelial cells. Most of the exchange of small molecules seems to occur through route 1. (b) Brain capillaries of the blood brain barrier lack pores, caveolae,
and intercellular clefts. (pp. 592–593, Fig. 20.5)
- Elastic arteries are the large, thick-walled arteries close to the heart. These arteries
contain many layers of elastin in their walls, especially in the tunica media. This large amount of elastin enables the arteries to withstand large pressure fluctuations by expanding when the heart contracts, forcing blood into them, and recoiling as blood flows
forward into the circulation during heart relaxation. The tunica media of elastic arteries contains substantial amounts of smooth muscle, but these vessels are not as active in vasoconstriction as are the muscular arteries. (pp. 589–591, Fig. 20.2)
Muscular arteries are medium- and smaller-sized arteries farther along the circulatory pathway that carry blood to specific body organs. Their tunica media contains proportionately more smooth muscle and less elastic tissue than that of elastic arteries. Muscular arteries are most active in vasoconstriction, although the elastin in their walls continues to dampen the pulsatile force produced by the heartbeat. (p. 591, Fig. 20.2)
Arterioles are the smallest of the arterial vessels, feeding directly into the capillary beds. Larger arterioles exhibit all three tunics, with tunica media being the thickest of these. The walls of the smaller arterioles are little more than smooth muscle cells that coil around the endothelium of the tunica intima. When arterioles constrict, the tissues served are largely bypassed. When the arterioles dilate, blood flow into the local capillaries
increases dramatically. (pp. 591–592, Fig. 20.2)
- (a) The examples of sinusoids in the chapter are within the bone marrow and spleen.
(p. 593) (b) A sinusoid is a wide, twisty, leaky capillary. (p. 593)
- The sketch of the cerebral arterial circle (of Willis) should resemble that in Figure 20.10c.
- (a) The two tributaries of the hepatic portal vein are the superior mesenteric vein and the splenic vein. (b) The function of the hepatic portal circulation is to deliver blood laden with nutrients from the stomach and intestine to the liver, where the nutrients are processed. (pp. 613 and 616)
- The azygos vein ascends along the right surface, or the center, of the bodies of the
thoracic vertebrae. It drains most systemic blood from the thorax region of the body.
(p. 611, Fig. 20.18)
- These are the superior left, superior right, inferior left, and inferior right pulmonary veins. (p. 596)
- Both are fetal vessels. Ductus venosus lies on the caudal surface of the liver and shunts some of the blood from the umbilical vein around the liver. Ductus arteriosus lies near the heart, connecting the pulmonary trunk to the arch of the aorta and shunting blood into the systemic circulation so as not to overload the pulmonary vessels in the nonfunctional fetal lungs. (pp. 622–623, Fig. 20.24)
- Arteriosclerosis (“hardening of the arteries”) is a general term for the pathological thickening and loss of elasticity of the arterial walls. Atherosclerosis is a specific term for the thickening of the tunica intima that narrows the arterial lumen because of deposits of atheromas in coronary arteries, resulting in strokes and heart attacks. (p. 619, “A Closer Look”)
- 1. The superficial temporal artery is a branch of the external carotid artery. 2. The facial artery is a branch of the external carotid artery. 3. The left common carotid artery branches from the aortic arch and the right common carotid artery branches from the brachiocephalic artery. 4. The brachial artery is a continuation of the axillary artery. 5. The radial artery branches from the brachial artery. 6. The femoral artery is a continuation of the external iliac artery. 7. The popliteal artery is a branch of the femoral artery. 8. The posterior tibial artery is a branch of the popliteal artery. 9. The dorsal pedis artery is the inferior continuation of the anterior tibial artery. (p. 598, Fig. 20.8a, b)
Critical Reasoning and Clinical Applications Questions
- Bacteria from infections in the danger triangle of the face can enter the facial vein, which communicates with the ophthalmic vein, which drains into the cavernous sinus, which is continuous with all other venous dural sinuses. Thus, infections may spread widely throughout the venous dural sinuses in the skull. (p. 611)
- Closing a patent foramen ovale is much more difficult and dangerous because it requires opening the heart—and open heart surgery is always difficult, especially in a small child. (p. 623, “Related Clinical Terms”)
- As evident in the figure, there are no major arteries in the center of the distal forearmRemember, Sam should survive. (Fig. 20.8a)
- The aneurysm was a balloon widening or outpocketing of a brain artery with weak walls that was compressing nearby nervous structures and in danger of bursting. The surgeons removed the aneurysm and replaced this arterial segment with a strong tube that will not burst. (p. 618, Fig. 20.24)
- In the absence of the pressure-dampening effect of the elastic arteries, the wall of arteries throughout the body must withstand pulses of higher maximum pressure. (pp. 589 and 591) Battered by higher than normal pressures, the arteries may eventually rupture, as occurs in some strokes, or may weaken and form an aneurysm. Atherosclerosis, a common type of arteriosclerosis, is described in detail in the A Closer Look box on p. 619.
- Because it is an artery, the internal thoracic artery (p. 602, Fig. 20.11) has a thicker wall than the saphenous vein (pp. 616–617. Fig. 20.23)Remember, it is less likely to be damaged by the pressure of the heartbeat or to develop atherosclerosis. As a result, the arterial graft lasts longer and leads to higher long-term rates of survival than the venous graft. Another advantage of using the internal thoracic artery is that it lies near the heartRemember, it need not be transplanted from some distant site in order to be grafted.
- Because both the ductus arteriosus and foramen ovale lead to a mixing of oxygen-rich pulmonary blood with oxygen-poor systemic blood after birth, the blood reaching the
tissues is not fully oxygenated. In such cases, the baby is blue from cyanosis. Still, the
affected babies can survive, and surgeons usually wait until the child is a few years old (and can better withstand the risks of thoracic surgery) before repairing the defects.
(p. 618, Fig. 20.25)
- (a) The venous blood in the legs has to travel the farthest distance to return to the heart, all “uphill” against gravity. Thus, the drainage of this blood may be slowed or halted,
especially in people who stand still for long periods. Pooling of blood in the veins of the lower limb puts backpressure on the valves and walls of these veinsRemember, that the valves may fail and the walls may stretch. (pp. 594–595) (b) Valves prevent backflow of blood, and they direct the flow of venous blood to the heart. In the neck, gravity directs venous blood in the proper direction anywayRemember, few valves are necessary—unlike in the lower limbs. (pp. 594–595)
Supplemental Student Materials
to Human Anatomy, Seventh Edition
Chapter 20: Blood Vessels
To the Student
Arteries, veins, and capillaries are dynamic structures that accomplish the delivery of blood throughout your body. The pulmonary circuit carries blood to the lungs for gas exchange, oxygen is picked up, and carbon dioxide is removed. The systemic circuit delivers oxygenated blood to the tissues of the body in exchange for carbon dioxide. As you study the vascular system, keep in mind that many arteries and deep veins are named the same and parallel with each other. Arteries always carry blood away from the heart, and veins always carry blood toward the heart. Regardless of type, vessels carrying oxygen-rich blood are colored red, and vessels carrying oxygen-poor blood are colored blue. First, learn the specific characteristics of blood vessels. Second, practice numerous blood-tracing problems to truly understand the “circuit” of blood circulation.
You will also find that incorporating Practice Anatomy Lab 3.0 (PAL) (BC; DVD, website) into your studies of the blood vessels will help you differentiate arteries from veins and learn the details of pulmonary and systemic circulation. For an excellent review of blood vessels, refer to the Cardiovascular System section of the Cadaver module. You may access PAL 3.0 through the DVD or the www.myaandp.com website.
Step 1: Describe the general characteristics of blood vessels.
__ Name the main types of vessels, describing the directional flow of blood within each type.
__ Describe the structure and function of three types of arteries, and name a body location for each.
__ Name the tunics of a blood vessel.
__ Clearly distinguish capillaries from sinusoids, naming body locations for each.
__ Explain the structural basis of capillary permeability.
__ Describe four routes involved in capillary permeability.
__ Distinguish a metarteriole from a thoroughfare channel.
__ Define precapillary sphincter, and describe its function.
__ Compare postcapillary venules to capillaries.
__ Explain how to histologically distinguish a vein from an artery, including comments on lumina and tunics.
__ Explain the function of valves in veins, and describe them on varicose veins.
__ Define vascular anastomoses, explain their functions, and identify body locations.
__ Define vasa vasorum, explain their functions, and name a couple of their locations.
Step 2: Review the heart and the great vessels.
__ Identify the major vessels associated with the heart.
__ Review how blood moves through the heart.
Step 3: Describe pulmonary circulation.
__ Name the major vessels of the pulmonary circuit.
__ Trace a drop of blood in the pulmonary trunk back to the left atrium.
__ Explain why pulmonary arteries are colored blue and pulmonary veins are colored red in Figure 20.7 in your .
Step 4: Describe systemic circulation.
__ List the major arteries, and name the part of the body they supply.
__ List the major veins that serve as tributaries for the superior and inferior venae cavae, naming the parts of the body that they drain.
__ Describe the special function of the hepatic portal system, and explain the significance of the portal-systemic anastomoses.
__ Diagram the pathway of the hepatic portal system using a flowchart format.
__ Name each part of the body drained by a vessel of the hepatic portal system.
__ Explain what makes a portal system extremely unique, and answer the question, “Does the human body have other portal systems and, if so, where?”
__ Trace a drop of blood from the kidney to the spleen.
__ Trace a drop of blood from the descending colon to the right hand.
__ Formulate several blood-tracing problems, and check your answers with your professor.
Step 5: Describe blood vessel disorders.
__ Distinguish atherosclerosis from arteriosclerosis (see “A Closer Look”).
__ Describe deep vein thrombosis of the lower limb.
__ Describe venous disease and the population it affects most.
__ Describe microangiopathy of diabetes.
__ Describe the various arteriovenous malformations.
Step 6: Describe fetal circulation.
__ Name fetal vessels that carry blood to and from the placenta, and describe the concentration of oxygen contained in them.
__ Define shunt.
__ Explain how the ductus venosus, ductus arteriosus, and foramen ovale function as fetal circulatory shunts.
__ Describe what happens to the ductus arteriosus and foramen ovale at birth.
__ Identify the adult structures derived from the ductus venosus, ductus arteriosus, foramen ovale, umbilical arteries, and umbilical vein.
__ Trace a drop of fetal blood from the placenta back to the placenta, including shunts.
Indicate regions of oxygen concentration (high, moderate, low, and very low) along the pathway.