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Chapter 20
1. What is the function of elastic fibers and smooth muscle in the tunica media of
arteries?
Ans: pg. 726 – allows the walls of the arteries to stretch easily or expand without
tearing in response to a small increase in pressure
2. In atherosclerosis, the walls of elastic arteries become less compliant (stiffer).
What effect does reduced compliance have on the pressure reservoir function of
arteries?
Ans: pg. 727 – less blood can be moved through the arteries
3. How are elastic arteries and muscular arteries structurally different?
Ans: pg. 727 – elastic arteries: high proportion of elastic fibers in their tunica
media, muscular arteries: more smooth muscle and fewer elastic fibers
4. State the functions of elastic arteries and muscular arteries.
Ans: pg. 727 – elastic arteries: help propel blood onward while the ventricles are
relaxing, muscular arteries: adjust the rate of blood flow and distribute blood to
various region of the body
5. Why do metabolically active tissues have extensive capillary networks?
Ans: pg. 730 - they use more oxygen and nutrients
6. What structural features of capillaries allow the exchange of materials between
blood and body cells?
Ans: pg. 730 – they are composed of only a single layer of endothelial cells and a
basement membrane so many substances can pass through them easily
7. Through which vessels does blood enter and leave a capillary bed?
Ans: pg. 730 – enters through a metarteriole and leaves through a thoroughfare
channel
8. How is blood flow directed through a capillary bed?
Ans: pg. 730 – by alternating contraction and relaxation of the smooth muscle of
metarterioles and the precapillary sphincter
9. Which vessel – the femoral artery or the femoral vein – has a thicker wall?
Which has a wider lumen?
Ans: pg. 732 – a) femoral artery, b) femoral vein
10. State the primary structural and functional differences between arteries, capillaries
and veins.
Ans: pg. 733 – arteries: smooth muscle and elastic fibers, conduct blood from the
heart to the body; capillaries: single-celled with only an endothelium and
basement membrane, permit exchange of nutrients and wastes between blood and
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interstitial fluid; veins: smooth muscle and elastic fibers with valves, return blood
to the heart
11. Why are valves more important in arm veins and leg veins than in neck veins?
Ans: pg. 732 – the valves aid in venous return by preventing the backflow of
blood
12. Referencing Figure 20.6, if your total blood volume is 5 liters, what volume is in
your venules and veins right now? In your capillaries?
Ans: pg. 733 – a) 3.2 liters, b) 3.5 liters
13. State the ways substances enter and leave blood plasma.
Ans: pg. 737 – diffusion, transcytosis, bulk flow
14. How do hydrostatic and osmotic pressures determine fluid movement across the
walls of capillaries?
Ans: pg. 734 – High blood hydrostatic pressure “pushes” fluid out of the
capillaries, while high osmotic pressure “pulls” fluid back into the capillaries
15. A person who has liver failure cannot synthesize the normal amount of plasma
proteins. How does a deficit of plasma proteins affect blood colloid osmotic
pressure? What is the effect on capillary filtration and reabsorption?
Ans: pg. 734 – a) deficit of plasma proteins: decreases the blood colloid osmotic
pressure, b) decreases reabsorption, increases capillary filtration
16. What happens to excess filtered fluid and proteins that are not reabsorbed?
Ans: pg. 736 – They enter lymphatic capillaries and are eventually returned by
the lymphatic system to the bloodstream
17. While exercising, your cardiac output increases. What happens to your total
blood flow? What happens to your mean arterial pressure?
Ans: pg. 737 – a) It will equal your cardiac output. b) mean arterial pressure will
increase
18. Which activity is occurring in the heart to produce systolic blood pressure?
Which heart activity is occurring during diastolic blood pressure?
Ans: pg. 737 – a) systole (contraction), b) diastole (relaxation)
19. What happens to blood pressure when a blood vessel’s distance from the left
ventricle increases? When you’re dehydrated? When dieting decreases adipose
tissue volume?
Ans: pg. 737, 738 – a) decreases, b) increases, c) decreases
20. What is vascular resistance and which factors contribute to it?
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Ans: pg. 737,738 – opposition to blood flow due to friction between blood and
the walls of the blood vessels, factors: size of the lumen, blood viscosity, total
blood vessel length
21. Which type of blood vessel exerts the most control over systemic vascular
resistance, and how does it achieve this?
Ans: pg. 738 – arteriole, by different diameters in different arterioles
22. Explain how the return of venous blood to the heart is accomplished.
Ans: pg. 738, 739 – Venous return is partly due to the pressure generated by
contraction of the left ventricle, by the skeletal muscle pump (contraction of
skeletal muscles in the limbs), by the respiratory pump alternating compression
and decompression of veins during inhalation and exhalation
23. Why is the velocity of blood flow slower in capillaries than in arteries and veins?
Of what benefit is a slow blood flow through capillaries?
Ans: pg. 739 – a) smaller size of the capillary, b) aids the exchange of materials
between blood and interstitial fluid
24. What are the principal inputs to and outputs from the cardiovascular center?
Ans: pg. 740, 741 – inputs: cerebral cortex, limbic system, hypothalamus;
outputs: sympathetic and parasympathetic neurons of the ANS
25. Following a drop in blood pressure, how does the baroreceptor reflex return blood
pressure to normal level? Does this negative feedback cycle happen when you lie
down or when you stand up?
Ans: pg. 741, 742 – a) they send nerve impulses at a slower rate to the
cardiovascular center, decreasing parasympathetic stimulation of the heart and
increasing sympathetic stimulation of the heart, increased secretion of epinephrine
and norepinephrine, b) when you stand up
26. What is the role of chemoreceptors in the regulation of blood pressure?
Ans: pg. 742 – monitor changes in blood levels of O2, CO2, and H+
27. How do hormones regulate blood pressure?
Ans: pg. 742,743 – altering cardiac output, changing systemic vascular
resistance, or adjusting the total blood volume
28. What is autoregulation and how does it differ in the systemic and pulmonary
circulations?
Ans: pg. 743, 744 – autoregulation: the ability of a tissue to automatically adjust
its blood flow to match its metabolic demands; in systemic circulation: walls of
the blood vessels dilate in response to low O2; in pulmonary circulation: walls of
the blood vessels constrict in response to low O2
29. What causes the pulse?
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Ans: pg. 746 – the alternate expansion and elastic recoil of an artery after each
contraction and relaxation of the left ventricle
30. How are systolic and diastolic blood pressures measured with a
sphygmomanometer?
Ans: pg. 746 – A cuff is placed on a bared arm. The cuff is inflated until the
brachial artery is compressed and blood flow stops. The cuff is deflated slowly
while the technician listens at the artery with a stethoscope. When the cuff is
deflated enough to allow the artery to open, the spurt of blood passing through the
artery is heard, the pressure is read as the systolic blood pressure. As the cuff is
deflated further, when the sounds become faint, the pressure is measured as the
diastolic blood pressure.
31. If a blood pressure is reported as “142 over 95”, what are the diastolic and systolic
pressures?
Ans: pg. 746 – 142 is systolic, 95 is diastolic
32. What is the relationship between anastomoses and collateral circulation?
Ans: pg. 748 – An anastomosis is the union of the branches of two or more
arteries supplying the same body region. Collateral circulation is the alternate
circulatory route of blood flow to a body part through an anastomosis.
33. In the adult, which are the only arteries that carry deoxygenated blood and the
only veins that carry oxygenated blood?
Ans: pg. 749 – Arteries that carry deoxygenated blood: pulmonary arteries; veins
that carry oxygenated blood: pulmonary veins
34. Why is less blood pressure needed in pulmonary arteries than systemic arteries?
Ans: pg. 750 – pulmonary arteries have larger diameters, thinner walls, and less
elastic tissue so the resistance to blood flow is very low
35. What is the main function of the systemic circulation?
Ans: pg. 751 – carries oxygenated blood from the heart to all parts of the body
and returns deoxygenated blood to the heart
36. After blood is ejected from the heart, what are the names of the four divisions of
the aorta, in order of blood flow?
Ans: pg. 751 – ascending aorta, arch of the aorta, thoracic aorta, abdominal aorta
37. Which general regions do each of the four principal divisions of the aorta supply?
Ans: pg. 755 – ascending aorta: myocardium of the heart; arch of the aorta: right
and left side of the head and neck, right and left upper limbs; thoracic aorta:
pericardium, bronchi of lungs, esophagus, structures in mediastinum, intercostals
and chest muscles, superior and posterior surfaces of diaphragm; abdominal aorta:
inferior surface of diaphragm, liver, stomach and esophagus, spleen, pancreas,
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small intestine, colon, adrenal glands, kidneys, reproductive structures, lower
limbs
38. Which branches of the coronary arteries supply the left ventricle? Why does the
left ventricle have such an extensive arterial blood supply?
Ans: pg. 756 – a) posterior interventicular branch, left anterior descending branch,
circumflex branch, b) must send blood to the body
39. What are the three major branches of the arch of the aorta, in order of their
origination?
Ans: pg. 756 – brachiocephalic trunk, left common carotid artery, left subclavian
artery
40. Which general regions do the arteries that arise from the arch of the aorta supply?
Ans: pg. 756, 759 – Right and left subclavian arteries: brain, spinal cord, neck,
shoulder, thoracic viscera and wall, scapular muscles; internal thoracic or
mammary artery: anterior thoracic wall and structures in the mediastinum;
vertebral artery: posterior portion of the brain, the cerebellum and pons, inner ear;
axillary artery: shoulder, thoracic and scapular muscles, humerus; brachial artery:
main blood supply to the arm; radial artery: wrist and hand; ulnar artery: ulnar
aspect of the forearm, wrist, palm; right common carotid artery: head; external
carotid artery: structures external to the skull; internal carotid artery: structures
internal to the skull
41. Which general regions do the visceral and parietal branches of the thoracic aorta
supply?
Ans: pg. 761 – visceral branches: pericardium, bronchi, pleurae, bronchial lymph
nodes, esophagus, mediastium; parietal branch: thoracic muscles, subcutaneous
tissue and skin, mammary glands, vertebrae, meninges, spinal cord, diaphragm
42. Which structure is the anatomic border between the thoracic and abdominal aorta?
Ans: pg. 763 – diaphragm
43. What are the paired and unpaired visceral branches of the abdominal aorta? What
is the general region that each branch supplies?
Ans: pg. 763, 767 – paired visceral branches: suprarenal, renal, gonadal arteries;
unpaired visceral branches: celiac trunk, superior mesenteric and inferior
mesenteric arteries; paired visceral branch supplies the kidneys, adrenal glands,
ureters, male and female reproductive organs; unpaired visceral branch supplies
the stomach and esophagus, pancreas, liver, gallbladder, small intestine, large
intestine
44. What are the paired and unpaired parietal branches of the abdominal aorta? What
is the general region that each branch supplies?
Ans: pg. 767 – paired parietal branch: inferior phrenic arteries, lumbar arteries;
unpaired parietal branch: median sacral artery; paired parietal branch supplies
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diaphragm, adrenal glands, lumbar vertebrae, spinal cord and its meninges,
muscles and skin of the lumbar region of the back; unpaired parietal branch
supplies the sacrum and coccyx
45. What are the two major branches of the common iliac arteries? Which general
regions do those arteries supply?
Ans: pg. 768,771 – internal iliac arteries and external iliac arteries; internal iliac
arteries supply the pelvis, buttocks, external genitals, thigh; external iliac arteries
supply the muscles of the anterior abdominal wall, the cremaster muscle in
males, round ligament of the uterus in females, lower limbs
46. Which general regions of the body are drained by the superior vena cava and the
inferior vena cava?
Ans: pg. 772 – superior vena cava: head, neck, chest, upper limbs; inferior vena
cava: abdomen, pelvis, lower limbs
47. Which vessels drain into the coronary sinus?
Ans: pg. 772 – great cardiac vein, middle cardiac vein, small cardiac vein
48. Into which veins in the neck does all venous blood from the head and neck drain?
Ans: pg. 774 – internal jugular, external jugular, vertebral veins
49. Which general areas are drained by the internal jugular, external jugular, and
vertebral veins?
Ans: pg. 776 – internal jugular: brain, face, neck; external jugular: scalp,
superficial and deep regions of the face; vertebral veins: deep structures in the
neck such as the cervical vertebrae, cervical spinal cord, and some neck muscles
50. Which regions of the upper limb are drained by the cephalic, basilic, median
antebrachial, radial, and ulnar veins?
Ans: pg. 780 – cephalic: lateral aspect of upper limbs; basilic: medial aspect of
upper limbs; median antebrachial: palms and forearms; radial: lateral aspects of
the forearms; ulnar: medial aspect of the forearms
51. Which vein provides collateral circulation between the cephalic and basilic veins?
Ans: pg. 780 – median cubital vein
52. From which vein in the upper limb is a blood sample often taken?
Ans: pg. 780 – medial cubital vein
53. Into which upper limb vein does lymph drain from the lymphatic system into the
circulatory system?
Ans: pg. 780 – subclavian
54. What is the importance of the azygos system relative to the inferior vena cava?
Ans: pg. 781 – may serve as a bypass for the inferior vena cava
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55. Which components of the azygos system drain the left side of the thorax? Into
which vein do they drain?
Ans: pg. 781 – a) hemiazygos vein and accessory hemiazygos vein, b) azygos
vein
56. Which vein returns blood from the abdominopelvic viscera to the heart?
Ans: pg. 784 – inferior vena cava
57. Which structures are drained by the lumbar, gonadal, renal, suprarenal, inferior
phrenic, and hepatic veins?
Ans: pg. 785 – lumbar: both sides of the posterior abdominal wall, vertebral canal,
spinal cord and meninges; gonadal: testes in the male and ovaries in the female;
renal: kidneys; suprarenal: adrenal glands; inferior phrenic: diaphragm; hepatiac:
liver
58. Which vein drains the medial side of the entire lower limb? The anterior leg?
The knee joint?
Ans: pg. 788 – a) great saphenous vein, b) anterior tibial veins, c) anterior tibial
veins
59. What is the clinical importance of the great saphenous veins?
Ans: pg. 788 – often used for prolonged administration of intravenous fluids
60. What is the main function of hepatic portal circulation?
Ans: pg. 789 – detours venous blood from the gastrointestinal organs and spleen
through the liver before it returns to the heart
61. Which veins carry nutrient-rich blood to the liver? Which veins carry oxygenrich blood to the liver?
Ans: pg. 789 – a) hepatic portal vein, b) proper hepatic artery
62. Which veins carry blood away from the liver?
Ans: pg. 789 – hepatic veins
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