Chapter 10
The Blood Vessels and Blood Pressure
TEST QUESTIONS
Multiple Choice
1. At rest which organ below receives the most blood flow?
(a) heart. (b) kidney. (c) brain. (d) muscle. (e) liver.
ANSWER: b
2. Resistance:
(a) is a measure of the hindrance to blood flow through a vessel caused by friction between the moving fluid and stationary vascular walls. (b) is doubled when the radius of the vessel is reduced by one-half.
(c) increases sixteen-fold when the radius of the vessel is reduced by one-half.
(d) both (a) and (b) above. (e) both (a) and (c) above.
ANSWER: e
3. Resistance increases when: (a) radius decreases. (b) length decreases. (c) viscosity decreases. (d) hematocrit decreases. (e) none of these answers.
ANSWER: a
4. Vasoconstriction:
(a) refers to a decrease in the radius of a vessel. (b) of an arteriole decreases blood flow through that vessel.
(c) of a vein increases blood flow through that vessel.
(d) both (a) and (b) above. (e) all of these answers.
ANSWER: e
5. Which of the following is the correct relationship between pressure, flow, and resistance?
(a) flow = pressure gradient radius4
(b) flow x pressure gradient = resistance
(c) flow = pressure gradient resistance
(d) pressure gradient = flow resistance
(e) resistance = flow radius4
ANSWER: c
6. Blood flow is affected by: (a) pressure differences. (b) the viscosity of the blood.
(c) the amount of friction in the blood vessels. (d) the length and diameter of the blood vessels. (e) all of these answers.
ANSWER: e
7. Vascular resistance is related to the: (a) length of a blood vessel. (b) diameter of a blood vessel. (c) nature of the blood flow. (d) viscosity of the blood. (e) all of these answers.
ANSWER: e
8. Vasoconstriction:
(a) causes a decrease in resistance.
(b) occurs when there is a decrease in the radius of a vessel.
(c) is due to a decrease in sympathetic activity. (d) two of these answers.
(e) all of these answers.
9. The major determinant influencing resistance to blood flow is the:
(a) viscosity of the blood.
(b) radius of the vessel through which the blood is flowing.
(c) pressure gradient in the vessel. (d) hematocrit of the blood. (e) amount of plasma protein.
ANSWER: b
10. In an arteriole, if the blood vessel radius is 2 units and then vasoconstricted to 1 unit, the resistance: (a) The resistance decreases 16 times.
(b) The resistance increases 16 times. (c) Flow will be decreased.
(d) Both (a) and (b) above. (e) Both (b) and (c) above.
ANSWER: e
11. The larger arteries assist with systemic blood flow to tissues by:
(a) contracting their tunica intima. (b) beating their semilunar-type valves. (c) by associating with large veins. (d) elastic recoil of their walls. (e) continuous vasoconstriction.
ANSWER: d
12. Which is not true of blood pressure? (a) Its maximal during ventricular systole. (b) It decreases the farther away from the heart. (c) Iit increases with increasing resistance. (d) It decreases with increasing vessel diameter. (e) It can be increased by direct parasympathetic activity.
ANSWER: e
13. Which of the following factors would produce the greatest change in blood flow?
(a) doubling the radius of the vessel.
(b) doubling the difference in the pressure gradient within the vessel.
(c) doubling the viscosity of the blood. (d) doubling the length of the vessel. (e) halving the viscosity of the blood.
ANSWER: a
14. Which type of blood vessel consists of only one cell layer?
(a) arteriole. (b) artery.
ANSWER: c
15. The microcirculation is composed of: (a) arteries, arterioles, and capillaries. (b) arterioles, capillaries, and venules. (c) arteries, capillaries, and venules. (d) arteries, arterioles, and venules. (e) none of these answers.
ANSWER: b
16. Organs that recondition the blood:
(a) receive disproportionately large percentages of the cardiac output.
(b) can withstand temporary reductions in blood flow much better than can organs that do not recondition the blood.
(c) must receive a constant blood supply in order to maintain homeostasis.
(d) both (a) and (b) above. (e) both (a) and (c) above.
ANSWER: d
17. The arteries:
(a) serve as rapid-transit passageways from the tissues to the heart because of their large radii. (b) act as a blood reservoir because they have the capacity to store large volumes of blood with little change in their internal pressure.
(c) are the major resistive vessels of the vasculature.
(d) are the site of exchange between the blood and surrounding tissues.
(e) none of these answers.
ANSWER: e
18. The major function of the arterioles is to: (a) regulate flow of blood through capillary beds. (b) distribute the cardiac output to tissues. (c) serve as a pressure reservoir.
(d) convert the intermittent flow from the heart to a steady outflow.
(e) both (a) and (b) above.
ANSWER: e
19. Because the arteries have large radii, they serve as excellent rapid-transit passageways for blood. Their second function, related to their elasticity, is to act as a __________ for maintaining blood flow during diastole.
(a) cardiac reserve (b) venous reserve (c) arterial capacitance
(d) lymphatic reserve (e) pressure reservoir
ANSWER: e
20. The pressure measured in the arteries just before the next ventricular ejection of blood is:
(a) systolic pressure. (b) diastolic pressure. (c) pulse pressure. (d) mean pressure. (e) none of these answers.
ANSWER: b
21. Select the correct statement about veins. (a) Their walls are highly muscular. (b)Their walls consist of one layer of cells. (c) There are only about forty large ones in the body.
(d) They serve as a blood reservoir.
(e) They transport blood away from the heart.
ANSWER: d
22. The pulse pressure is the:
(a) difference between the systolic and diastolic pressures.
(b) average pressure throughout the cardiac cycle. (c) maximum pressure exerted in the arteries. (d) minimum pressure exerted in the arteries. (e) change in pressure that can be felt in an artery due to shutting of the aortic valve.
ANSWER: a
23. Mean arterial pressure is:
(a) diastolic pressure + (systolic/3). (b) systolic pressure + (pulse pressure/3). (c) diastolic pressure + (pulse pressure/3). (d) pulse pressure - (diastolic pressure/3). (e) pulse pressure + (systolic pressure/3).
ANSWER: c
24. If the arterial blood pressure is recorded at 132/84, what is the mean arterial pressure?
(a) 100 mm Hg (b) 93 mm Hg (c) 108 mm Hg (d) 48 mm Hg
(e) none of these answers.
25. If the pulse pressure is 44 mm Hg and the diastolic pressure is 68 mm Hg, the systolic pressure is ___ mm Hg.
(a) 22 (b) 24 (c) 66 (d) 112 (e) 145
ANSWER: d
26. What force continues to drive blood through the vasculature during ventricular diastole?
(a) Ventricular contraction forces blood into the vasculature during ventricular diastole.
(b) The elastic recoil of the stretched arterial walls provides the force to continue blood flow in the remaining vascular system during ventricular diastole.
(c) Sympathetic stimulation produces arterial vasoconstriction, which drives the blood forward into the arterioles during ventricular diastole. (d) Skeletal muscle contraction squeezes the blood forward from the arteries during ventricular diastole.
(e) Respiratory movements produce pressure changes in the chest, which establishes a pressure gradient that drives blood forward from the arteries into the microcirculation.
ANSWER: b
27. Which of the following factors is most important in matching the blood flow through a specific tissue with the metabolic needs of that tissue? (a) Sympathetically induced vasoconstriction of the arteries supplying a tissue forces more blood to flow into the tissue.
(b) Parasympathetically induced vasodilation of the capillaries within a tissue allows more blood to flow into the tissue.
(c) Local changes within a tissue resulting from increased metabolic activity can produce local arteriolar vasodilation to allow more blood to flow into the tissue.
(d) Widespread venous vasoconstriction allows blood to dam up at the tissue level.
(e) The amount of blood flowing through each tissue remains constant through reflex controls to ensure that metabolic needs are continuously met.
28. Which of the following properties does not pertain to the arterioles?
(a) Their radii cannot be changed.
(b) Their walls contain a thick layer of smooth muscle.
(c) They are responsible for the distribution of blood flow to the various organs.
(d) They are the major vessels that contribute to total peripheral resistance.
(e) They are richly innervated by sympathetic nerve fibers.
ANSWER: a
29. As metabolic activity of an organ or tissue increases, blood flow to that organ increases. This phenomenon is known as:
(a) pressure autoregulation. (b) tissue anoxia.
(c) active hyperemia. (d) hypertension. (e) atherosclerosis.
ANSWER: c
30. The following local chemical changes occur during a period of increased cell activity except: (a) increased CO2.
(b) increased acid. (c) increased O2.
(d) increased K+.
(e) increased osmolarity.
ANSWER: c
31. All of the following local chemical factors will cause vasodilation of arterioles, except: (a) decreased K+.
(b) increased CO2.
(c) increased acid. (d) decreased O2.
(e) histamine release.
ANSWER: a
32. Increased respiration within a tissue leads to vasodilation of arterioles because:
(a) Carbon dioxide levels increase. (b) Oxygen levels decrease.
(c) Parasympathetic activity increases. (d) Parasympathetic activity decreases. (e) Both (a) and (b) above.
ANSWER: e
33. Endothelial-derived relaxing factor (EDRF) is:
(a) a local chemical mediator released from the endothelial cells that induces relaxation of arteriolar smooth muscle in the vicinity. (b) adenosine.
(c) nitric oxide.
(d) both (a) and (b) above. (e) both (a) and (c) above.
ANSWER: e
34. Which statements about nitric oxide is wrong? (a) NO increases the total peripheral resistance by its action on arteriolar smooth muscle.
(b) NO serves as endothelial-derived relaxing factor.
(c) NO is the direct mediator of penile erection. (d) NO is released as “chemical warfare” by macrophages of the immune system.
(e) NO serves as a novel type of neurotransmitter in the brain.
ANSWER: a
35. Extrinsic control of arteriolar radius:
(a) is accomplished primarily by the sympathetic nervous system.
(b) is important in the regulation of arterial blood pressure.
(c) can be overridden by local adjustments. (d) is accomplished primarily by the sympathetic nervous system and is important in the regulation of arterial blood pressure.
(e) all of these answers.
ANSWER: e
36. During strenuous exercise, blood flow increases to:
(a) the heart because of local control factors. (b) the brain because of reflex control factors. (c) the skeletal muscles because of local control factors.
(d) both (a) and (c) above. (e) all of these answers.
ANSWER: d
37. Most sympathetic fibers release ________ at the arterioles.
(a) acetylcholine. (b) dopamine. (c) GABA. (d) glycine. (e) norepinephrine.
38. The major site of sympathetic blood flow control (resistance changes) is at the:
(a) arterioles. (b) capillaries. (c) metarterioles. (d) arteries. (e) veins.
ANSWER: a
39. Each of the following local factors produces the relaxation of arteriolar smooth muscle except increased:
(a) acid.
(b) carbon dioxide. (c) osmolarity. (d) oxygen. (e) potassium.
ANSWER: d
40. The myogenic response:
(a) refers to vascular smooth muscle’s tendency to constrict when blood flow increases.
(b) refers to vascular smooth muscle’s tendency to relax when blood flow increases.
(c) refers to vascular smooth muscle’s tendency to constrict when stretched.
(d) refers to vascular smooth muscle’s tendency to dilate when stretched.
(e) none of these answers.
ANSWER: c
41. The major resistance vessels of the body are the: (a) arteries.
(b) arterioles. (c) capillaries. (d) lymphatics. (e) veins.
ANSWER: b
42. Which does not cause arteriolar vasodilation? (a) decreased sympathetic stimulation. (b) local decrease in O2.
(c) histamine release. (d) application of heat.
(e) myogenic response to passive stretch of the vessel.
ANSWER: e
43 During exercise, there is not an increased blood flow to which of the following tissues?
(a) Skeletal muscles.
(b) Heart. (c) Skin. (d) Brain.
(e) Blood flow is increased to all of these tissues during exercise.
ANSWER: d
44. Which factor would reduce total peripheral resistance?
(a) adrenal medulla hormones. (b) angiotensin II.
(c) increased hematocrit. (d) anaphylaxis.
(e) cardiovascular center activity.
ANSWER: d
45. Binding of epinephrine to alpha receptors causes: (a) smooth muscle relaxation in arteries.
(b) smooth muscle relaxation in skeletal muscle arteries.
(c) smooth muscle constriction in skeletal muscle arteries.
(d) smooth muscle relaxation in coronary arteries. (e) none of these answer.
ANSWER: b
46. Active hyperemia:
(a) refers to the arteriolar dilation that occurs within a tissue in response to local chemical changes that accompany increased metabolic activity of the tissue.
(b) refers to local arteriolar mechanisms that are aimed at keeping tissue blood flow fairly constant in spite of rather wide deviations in mean arterial driving pressure.
(c) refers to the increase in blood flow to a tissue that occurs after removal of an occlusion of its blood supply.
(d) is important in maintaining an adequate pressure head to drive blood forward into a tissue. (e) none of these answers.
ANSWER: a
47. Which of the following is not a characteristic of capillaries?
(a) thin walls.
(b) short distance between adjacent vessels. (c) distensible walls.
(d) slow blood velocity. (e) large total surface area.
48. The largest total cross-sectional area is found in the:
(a) aorta. (b) arterioles. (c) capillaries. (d) venules. (e) veins.
ANSWER: c
49. Through which vessel is the velocity of blood flow the slowest?
(a) aorta. (b) arterioles. (c) capillaries. (d) venules. (e) veins.
ANSWER: c
50. The velocity of blood flow in capillaries: (a) is greater than that for arterioles. (b) is greater than that for veins.
(c) is slow enough to favor adequate exchange. (d) both (a) and (b) above.
(e) both (a) and (c) above.
ANSWER: c
51. As the total cross-sectional area of the vascular tree __________, the velocity of blood flow __________.
(a) increases, decreases (b) increases, increases (c) decreases, decreases (d) increases, remains constant (e) decreases, remains constant
ANSWER: a
52. Glucose, a water-soluble, lipid-insoluble substance, crosses capillary walls:
(a) through water-filled pores. (b) directly through endothelial cells.
(c) through water-filled pores and endothelial cells.
(d) through gap junctions. (e) none of these answers.
ANSWER: a
53. The movements of fluid across the capillary wall depend on all of the following except:
(a) capillary blood pressure.
(b) interstitial-fluid hydrostatic pressure. (c) plasma protein concentration.
(d) interstitial-fluid protein concentration. (e) concentration of glucose in the capillary.
ANSWER: e
54. The process of ultrafiltration:
(a) is movement of protein-free plasma from the capillaries into the interstitial-fluid.
(b) occurs when the outward forces (capillary blood pressure plus interstitial-fluid-colloid osmotic pressure) exceed the inward forces (blood-colloid osmotic pressure plus interstitial-fluid hydrostatic pressure).
(c) occurs when the outward forces (capillary blood pressure plus blood-colloid osmotic pressure exceed the inward forces (interstitial-fluid hydrostatic pressure plus interstitial-( interstitial-fluid-colloid osmotic pressure).
(d) both (a) and (b) above. (e) both (a) and (c) above.
ANSWER: d
55. Reabsorption occurs:
(a) when inward-driving pressures exceed the outward-driving pressures across the capillary wall.
(b) when outward-driving pressures exceed the inward-driving pressures across the capillary wall. (c) due to increased osmolarity of plasma in the venule end of the capillary.
(d) both (a) and (c) above. (e) both (b) and (c) above.
ANSWER: d
56. Which two pressures act to move fluid into the capillary?
(a) interstitial-fluid hydrostatic pressure and capillary blood pressure.
(b) blood-colloid osmotic pressure and interstitial-fluid-colloid osmotic pressure.
(c) interstitial-fluid hydrostatic pressure and blood-colloid osmotic pressure.
(d) interstitial-fluid hydrostatic pressure and interstitial-fluid-colloid osmotic pressure. (e) capillary blood pressure and interstitial-fluid-colloid osmotic pressure.
ANSWER: c
57. Fluid movement into and out of the capillary is dependent on __________ and __________ pressures working in __________ direction(s). (a) hydrostatic, osmotic, opposite
(c) filtration, absorption, the same (d) length, filling, the same
(e) protein content, blood pressure, the same
ANSWER: a
58. The principle force that causes movement of fluid from the tissues into the capillaries is the:
(a) hydrostatic pressure of the venous. (b) hydrostatic pressure of the arterial blood. (c) osmotic pressure created by the plasma proteins.
(d) pressure of the lymph. (e) none of these answers.
ANSWER: c
59. What is the primary method by which materials such as O2, CO2 and nutrients are exchanged
between the blood and surrounding tissues? (a) passive diffusion of substances across the capillary wall down their concentration gradients. (b) active transport of materials across the capillary wall.
(c) osmotic pressure drawing water and solutes out of the capillary and bringing these dissolved nutrients into contact with the tissue cells. (d) processes of ultrafiltration and reabsorption. (e) bulk flow.
ANSWER: a
60. Given the following parameters, what would the reabsorption pressure be?
- blood capillary pressure at arteriolar end of tissue capillaries: 35 mm Hg
- blood capillary pressure at venule end of tissue capillaries: 15 mm Hg
- blood-colloid osmotic pressure: 22 mm Hg - interstitial-fluid hydrostatic pressure: 1 mm Hg - interstitial-fluid-colloid osmotic pressure: 0 mm Hg.
(a) 6 mm Hg (b) 7 mm Hg (c) 8 mm Hg (d) 10 mm Hg (e) 22 mm Hg
ANSWER: c
61. Given the following forces acting at a given point across the capillary wall, what type of fluid movement will be taking place at that point? - Capillary blood pressure = 32 mm Hg - Blood-colloid osmotic pressure = 23 mm Hg - Interstitial-fluid hydrostatic pressure = 1 mm Hg
- Interstitial-fluid-colloid osmotic pressure = 0 mm Hg
(a) Ultrafiltration will occur with a net outward pressure of 8 mm Hg.
(b) Ultrafiltration will occur with a net outward pressure of 10 mm Hg.
(c) Ultrafiltration will occur with a net outward pressure of 56 mm Hg.
(d) Reabsorption will occur with a net inward pressure of 24 mm Hg.
(e) Reabsorption will occur with a net inward pressure of 10 mm Hg.
ANSWER: a
62. Which change will increase fluid reabsorption by the capillaries?
(a) decreased interstitial-fluid hydrostatic pressure. (b) increased capillary blood pressure.
(c) increased blood-colloid osmotic pressure. (d) increased interstitial-fluid-colloid osmotic pressure.
(e) none of these answers.
ANSWER: c
63. Which of the following alterations could lead to edema?
(a) a fall in capillary blood pressure.
(b) a fall in the concentration of plasma proteins. (c) blocked lymph vessels.
(d) both (a) and (b) above. (e) both (b) and (c) above.
ANSWER: e
64. What is the primary reason that edema may occur with serious burns?
(a) increased venous pressure due to interference with circulation through scarring in the burned area.
(b) lowering of blood-colloid osmotic pressure due to the loss of protein-rich fluid from the surface of the burn.
(c) blockage of lymphatic drainage from the burned area.
(d) loss of protein in the urine. (e) increased tissue pressure.
ANSWER: b
65. Edema could result from:
(b) blockage of lymph vessels and increased capillary blood pressure.
(c) increased capillary blood pressure and decreased blood-colloid osmotic pressure. (d) blockage of lymph vessels and decreased blood-colloid osmotic pressure.
(e) none of these answers.
ANSWER: a
66. Each of the following factors promotes the function of the capillaries except:
(a) a blood pressure forcing fluid out of these vessels.
(b) a small total surface area.
(c) an osmotic pressure drawing fluid into these vessels.
(d) pores in the endothelial wall. (e) thin walls.
ANSWER: b
67. Which of the following conditions might be associated with edema?
(a) extensive burns. (b) congestive heart failure. (c) blocked lymphatics. (d) increased venous pressure. (e) all of these answers.
ANSWER: e
68. Which of the following is not a function of the lymphatic system?
(a) defense against disease.
(b) return of fluid to the circulatory system. (c) transport of fat molecules.
(d) regulation of sodium balance.
(e) return of proteins to the circulatory system.
ANSWER: d
69. The veins:
(a) act as low-resistance passageways for blood flow from the tissues to the heart.
(b) can serve as a blood reservoir by adjusting their total capacity to accommodate variations in blood volume.
(c) contain one-way valves that prevent the backflow of blood.
(d) both (a) and (c) above. (e) all of these answers.
ANSWER: e
70. Which vessels can act as a blood reservoir by adjusting their total capacity to accommodate variations in blood volume?
(a) arteries. (b) arterioles. (c) capillaries. (d) veins.
(e) lymph vessels.
ANSWER: d
71. Which vessels contain the highest percentage of total blood volume?
(a) pulmonary veins. (b) pulmonary arteries. (c) systemic veins. (d) systemic arteries. (e) coronary arteries.
ANSWER: c
72. The venous valves:
(a) actively contract to force blood uphill against gravity.
(b) passively close to prevent the backflow of blood in the veins.
(c) are positioned at the entrances to the atria. (d) both (b) and (c) above.
(e) all of these answers.
ANSWER: b
73. Heart and venous valves serve a similar function. They prevent a __________ flow of blood. (a) forward.
(b) backward. (c) turbulent. (d) pulsatile. (e) laminar.
ANSWER: b
74. The walls of the veins contain smooth muscle innervated by sympathetic nerve fibers. Sympathetic stimulation _________ venous pressure and drives __________ blood into the heart.
(a) increases, more. (b) increases, less. (c) decreases, more. (d) decreases, less. (e) none of these answers.
75. Which of the following factors aids venous return to the heart?
(a) Sympathetic stimulation increases venous pressure.
(b) Skeletal muscle pump squeezes blood through the veins.
(c) Respiratory pump provides a pressure gradient between the lower and chest veins.
(d) Venous valves prevent backflow of blood. (e) All of these answers.
ANSWER: e
76. Increased venous return:
(a) is encouraged by vasocontraction.
(b) occurs when heart has greater contractility. (c) is enhanced by salt retention.
(d) both (a) and (b) above. (e) all of these answers.
ANSWER: e
77. The two determinants of mean arterial pressure are _________ and __________.
(a) stroke volume, compliance of vessel walls. (b) heart rate, stroke volume.
(c) heart rate, end-diastolic volume.
(d) cardiac output, total peripheral resistance. (e) none of these answers.
ANSWER: d
78. Which factor does not positively affect blood pressure?
(a) skeletal muscle activity. (b) aldosterone release. (c) renin release.
(d) calcium reabsorption. (e) increased venous return.
ANSWER: d
79. Mean arterial blood pressure:
(a) equals stroke volume times heart rate. (b) is 91 mm Hg when the blood pressure is recorded as 117/78.
(c) is 97.5 mm Hg when the blood pressure is recorded as 117/78.
(d) both (a) and (b) above. (e) both (a) and (c) above.
ANSWER: b
80. When the blood pressure becomes elevated above normal:
(a) The carotid-sinus and aortic-arch baroreceptors increase their rate of firing.
(b) The cardiovascular control center decreases sympathetic and increases parasympathetic activity to the heart and blood vessels. (c) Arteriolar vasodilation occurs as a compensatory response.
(d) Two of these answers. (e) All of these answers.
ANSWER: e
81. Short term adjustments in blood pressure are mediated by:
(a) baroreceptor reflexes. (b) changes in cardiac output. (c) renal activity
(d) both (a) and (b) above. (e) both (b) and (c) above.
ANSWER: d
82. Which of the following does not occur to compensate for a fall in blood pressure below normal?
(a) Cardiac output is increased.
(b) Total peripheral resistance is decreased. (c) Heart rate is increased.
(d) Venous vasoconstriction occurs. (e) Stroke volume is increased.
ANSWER: b
83. Which statement regarding sympathetic
stimulation effects on blood pressure is incorrect? (a) vasoconstriction of arterioles increases total peripheral resistance.
(b) decreased end diastolic volume increases cardiac output.
(c) increased stroke volume increases cardiac output.
(d) vasoconstriction of veins increases venous return
(e) vasoconstriction of veins increases stroke volume.
ANSWER: b
84. Receptors that detect changes in the blood pressure are located in the:
ANSWER: a
85. Regulation of arterial pressure is mediated by reflex mechanisms. One important pressure receptor, a __________, is located in the _________.
(a) chemoreceptor, carotid sinus. (b) exteroceptor, carotid sinus. (c) baroreceptor, carotid sinus. (d) chemoreceptor, skeletal muscles. (e) baroreceptor, skeletal muscles.
ANSWER: c
86. The vasomotor center responds to rising H+/CO 2
by:
(a) vasodilating arteries. (b) vasoconstricting arteries. (c) increasing respiratory rate. (d) inhibiting cardioinhibitory center. (e) stimulating cardioacceleratory center.
ANSWER: b
87. Each of the following will cause an increase in blood pressure except one. Identify the exception. (a) increased levels of aldosterone.
(b) increased levels of angiotensin II. (c) increased blood volume.
(d) increased levels of oxygen. (e) increased levels of vasopressin.
ANSWER: d
88. When the receptor potential of the baroreceptors decreases, the cardiovascular center responds by bringing about an increase in:
(a) stroke volume. (b) venous return.
(c) total peripheral resistance. (d) two of these answers. (e) all of these answers.
ANSWER: e
89. A sudden increase in pressure within the carotid sinus leads to:
(a) increased sympathetic nerve activity. (b) increased sympathetic nerve activity and decreased parasympathetic nerve activity. (c) decreased sympathetic nerve activity and increased parasympathetic nerve activity. (d) decreased sympathetic nerve activity. (e) none of these answers.
ANSWER: c
90. __________ refers to a chronic state of increased arterial pressure:
(a) shock.
(b) congestive heart failure. (c) pulmonary edema. (d) angina pectoris. (e) hypertension.
ANSWER: e
91. Which of the following does not occur as a compensation for hemorrhage?
(a) shift of fluid from the interstitial fluid into the plasma.
(b) reduced urinary output.
(c) increased capillary permeability. (d) increased cardiac output.
(e) increased synthesis of plasma proteins.
ANSWER: c
92. Hypertension may be caused by all of these except:
(a) renal disease.
(b) hardening of the arteries. (c) suppression of baroreceptors. (d) salt imbalances.
(e) adrenal medullary tumors.
ANSWER: c
93. Shock may develop: (a) from loss of blood. (b) from low cardiac output. (c) from anaphylaxis. (d) excess vasodilation. (e) all of these answers.
ANSWER: e
94. Which is not a compensation mechanism for blood loss?
(a) fluid shift from ICF to plasma. (b) venous vasoconstriction.
(c) lowered angiotensin II production. (d) thirst.
(e) increased renal reabsorption of salt and water.
ANSWER: c
95. Varicose veins develop mainly from the incompetent function of the
(a) connective tissue lining. (b) endothelium.
(e) valves.
ANSWER: e
96. Baroreceptors are most sensitive to changes in the (a) blood pressure.
(b) carbon dioxide level in the blood. (c) degree of contraction of skeletal muscles. (d) oxygen level in the blood.
(e) pH of the ECF.
ANSWER: a
True/False
97. Organs that recondition the blood normally receive considerably more of the cardiac output than is necessary to meet their metabolic needs.
ANSWER: True
98. Organs that do not adjust the blood are more vulnerable to reductions in blood flow than are organs that perform homeostatic functions on the blood.
ANSWER: True
99. If driving pressure is constant, flow will double when the radius increases by two-fold.
ANSWER: False
100.Resistance to blood flow increases as the viscosity of the blood increases.
ANSWER: True
101.Arteries ensure that blood constantly flows due to contraction of its smooth muscle layer.
ANSWER: False
102.Arteries that have lowered compliance are not as elastic.
ANSWER: True
103.Vasoconstriction refers to a decrease in the radius of a vessel.
ANSWER: True
104.A major function of the arteries is to serve as a blood reservoir.
ANSWER: False
105.More blood is delivered to the tissues during ventricular systole than during ventricular diastole.
ANSWER: False
106.As the concentration of red blood cells increases in the blood, the viscosity of the blood increases.
ANSWER: True
107.When the heart is not ejecting blood into the arterial system, the pressure in the arteries falls to zero as blood drains off into the rest of the vasculature.
ANSWER: False
108.There is a constant flow of blood through the capillaries even though the heart is forcing blood out into the arterial system only part of the time.
ANSWER: True
109.The sphygmomanometer and stethoscope can be used for a direct measurement of arterial blood pressure.
ANSWER: False
110.Measurement of arterial pressure using a
sphygmomanometer is possible because turbulent blood flow that occurs as arterial pressure overcomes a partially occluded artery and can be heard by a stethoscope placed just over the artery.
ANSWER: True
111.Arterial walls contain a thick layer of smooth muscle and an abundance of collagen and elastin fibers.
ANSWER: True
112.The pulse pressure is the maximum pressure exerted in the arteries.
ANSWER: False
113.If the diastolic pressure and systolic pressure were both increased by 10 mm Hg, then the pulse pressure would also be increased by 10 mm Hg.
114.For a blood pressure reading of 136/78, 78 refers to the diastolic pressure.
ANSWER: True
115.Local control mechanisms can override sympathetic control of changes in the size of arterioles.
ANSWER: True
116.During exercise, blood flow to the digestive tract is increased by dilation of the arterioles of the digestive tract.
ANSWER: False
117.The mean arterial pressure is a simple average of the systolic and diastolic pressures.
ANSWER: False
118.Arteriolar resistance is regulated by both local controls and extrinsic controls.
ANSWER: True
119.Histamine released in injured areas produces local arteriolar vasodilation.
ANSWER: True
120.Differences in blood flow to an organ are related to the resistance to flow offered by the arterioles that supply that organ.
ANSWER: True
121.The regulation of blood flow in the arterioles of the brain is mainly under the control of the sympathetic nervous system.
ANSWER: False
122.Hyperemia occurs in response to circulating epinephrine.
ANSWER: False
123.By F = P/R, as resistance increases the flow increases if the pressure is constant.
ANSWER: False
124.Increased sympathetic stimulation causes generalized vasoconstriction.
ANSWER: True
125.The greatest pressure drop in the vascular system occurs within the capillaries due to fluid leaving the capillaries by the process of ultrafiltration.
ANSWER: False
126.A local increase in potassium increases the vasodilation of arterioles.
ANSWER: True
127.The extra fluid filtered but not reabsorbed at the capillary level is picked up by the lymphatics.
ANSWER: True
128.The ultimate function of the circulatory system is accomplished by the heart.
ANSWER: False
129.All the fluid forced out of the capillaries is filtered through the lymphatics before being returned to the venous blood.
ANSWER: False
130.During exercise, a larger percentage of the cardiac output travels to the skin and skeletal muscles.
ANSWER: True
131.Increased tissue respiration rates cause local vasodilation of arterioles.
ANSWER: True
132. Blood flow is driven by osmotic pressure.
ANSWER: False
133.Velocity of blood flow is the slowest in the veins because the blood must move uphill against gravity in these vessels.
ANSWER: False
134.Endothelin causes arteriolar smooth muscle contraction.
135.The primary means by which individual
substances are exchanged between the blood and surrounding tissues is by bulk flow.
ANSWER: False
136.The main process by which exchange of solutes occurs between the blood and interstitial fluid at the capillary level is passive diffusion down concentration gradients.
ANSWER: True
137.Glucose is actively transported across the capillary walls.
ANSWER: False
138.Vasopressin is a vasodilator.
ANSWER: False
139.Plasma proteins are responsible for the blood-colloid osmotic pressure.
ANSWER: True
140.There is normally a net loss of fluid from the capillary at the arteriolar end.
ANSWER: True
141.There is normally a net gain of fluid in the capillary at the venular end.
ANSWER: True
142.The colloidal osmotic pressure in the blood plasma draws fluid into the capillary.
ANSWER: True
143.The capillary vessel walls are more permeable than the lymphatic vessel walls.
ANSWER: False
144.The capillaries have an overall, tremendous cross-sectional area.
ANSWER: True
145.Normally most of the blood at any one time is in the capillary beds, because this is where material exchange is taking place.
ANSWER: False
146.Sympathetic activity controls the degree of resistance in arterioles.
ANSWER: True
147.Bulk flow refers to the volume of blood ejected by each ventricle each minute.
ANSWER: False
148.At any point in time most of the blood flow in the body is contained in the capillaries.
ANSWER: False
149.The vessels with the greatest total cross-sectional area are the arteries.
ANSWER: False
150.Because the capillaries have the smallest radii of any vascular segment, they are the major resistive vessels.
ANSWER: False
151.A decrease in blood-colloid osmotic pressure will decrease ultrafiltration and increase reabsorption at the capillary level.
ANSWER: False
152.Edema refers to excess interstitial fluid.
ANSWER: True
153.Blood flows continuously through all capillaries.
ANSWER: False
154.The skeletal muscle pump adds to the effect of gravity on the venous system.
ANSWER: True
155.Cardiac contraction induces blood flow in the arterial system, but it has no influence on blood flow in the veins.
ANSWER: False
ANSWER: True
157.The effective circulating volume is reduced when blood collects in distended varicose veins. ANSWER: False
158.A metarteriole is located between an arteriole and venule.
ANSWER: True
159.The flow rate of blood is the same in all segments of the vascular tree, but the velocity of blood flow is slower in the capillaries than in other segments of the vascular tree.
ANSWER: True
160.Cardiovascular changes associated with exercise can be accounted for by local metabolic influences on skeletal muscle arterioles coupled with adjustments via the baroreceptor reflex.
ANSWER: False
161.Primary hypertension refers to chronically elevated blood pressure of unknown origin.
ANSWER: True
162.The baroreceptors are usually no longer functional in the presence of hypertension.
ANSWER: False
163.The interstitial fluid is not part of the ECF.
ANSWER: False
164.Irreversible shock occurs when the cardiovascular system itself starts to deteriorate as a consequence of side effects from compensatory measures to the severe hypotension.
ANSWER: True
Fill-in-the-Blank
165.Two functions of arteries are ______________ and _______________.
ANSWER: passageway to tissues, pressure reservoir
166.The wall of an artery contains ________ and ________ connective tissue fibers.
ANSWER: collagen, elastin
167.Arteriolar smooth muscle normally displays a state of partial constriction known as
_____________________.
ANSWER: tone
168.Relaxation of arteriolar smooth muscle causes the radius of the vessel to _______________, a process known as ___________________, whereas contraction of arteriolar smooth muscle causes the radius of the vessel to ___________, a process known as _________________.
ANSWER: increase, vasodilation, decrease, vasoconstriction
169.What category of controls (local or extrinsic) is primarily responsible for matching tissue blood flow with the metabolic needs of the specific tissue involved? ___________________
ANSWER: local
170.The two hormones primarily involved in fluid balance that are also potent vasoconstrictors are ________________ and __________________.
ANSWER: vasopressin, angiotensin II
171.Blood flow is driven by ____________.
ANSWER: mean arterial pressure
172. Movement of fluid out of the capillaries into the interstitial fluid is known as ____________.
ANSWER: ultrafiltration
173.Movement of fluid from the interstitial fluid into the plasma is known as _______________.
174.Accumulation of excess interstitial fluid is known as ______________________.
ANSWER: edema
175.A capillary wall has a measured thickness of about one ________.
ANSWER: micrometer
176.The primary mechanism for exchange of individual solutes across the capillary wall is __________________.
ANSWER: diffusion down individual concentration gradients
177.The process of ____________________ is responsible for determining the distribution of the extracellular fluid volume between the plasma and interstitial fluid.
ANSWER: bulk flow
178.A deficiency of ______________ in the blood reduces the blood-colloid osmotic pressure.
ANSWER: plasma proteins
179.Mean arterial pressure = _______________ x _______________.
ANSWER: cardiac output, total peripheral resistance
180. Cardiac output = [EDV - ______] x heart rate.
ANSWER: ESV
181.Total peripheral resistance is primarily dependent on ________________________________.
ANSWER: the degree of arteriolar vasoconstriction
182.The receptors for the baroreceptor reflex are located in the ____________ and
______________, whereas the integrating center is the ________________ located in the
____________________. The efferent pathway for this reflex is the ______________. The effector organs are the _______________ and _______________.
ANSWER: carotid sinus, aortic arch, cardiovascular control center, medulla, autonomic nervous system, heart, blood vessels
183.Assume a person has a blood pressure recording of 125/77.
(a) What is the systolic pressure? ________________
(b) What is the diastolic pressure? _______________
(c) What is the pulse pressure? ___________________
(d) What is the mean arterial pressure? ___________
(e) Would any sound be heard when the pressure in an external cuff around the arm was 130 mm Hg? _______
(f) Would any sound be heard when cuff pressure was 118 mm Hg? ________
(g) Would any sound be heard when cuff pressure was 75 mm Hg? ________
ANSWER: a. 125, b. 77, c. 48, d. 93, e. no, f. yes, g. no
184.Normally capillary filtration exceeds reabsorption by about ________ liters daily.
ANSWER: three
185.Venous capacity depends on the _________ of the vein walls.
ANSWER: distensibility
186.Vasoconstriction of blood vessels changes the flow of blood through them by ________ it.
ANSWER: decreasing
187.The skeletal muscle pump changes venous return by _________ it.
ANSWER: increasing
188._________ are structures in veins that prevent the blood from flowing backwards.
ANSWER: Valves
189.Baroreceptors are mainly found in the carotid sinus and ________.
ANSWER: aortic arch
190.Hypertension occurs if the systolic/diastolic pressure is above the values of ________.
191.________ syndrome occurs with the increased production of the hormone ________.
ANSWER: Conn’s, aldosterone
192.Vasogenic shock is triggered by widespread _________ of blood vessels.
ANSWER: vasodilation
Matching
193.Indicate which type of vessel performs the function listed by writing the appropriate letter in the blank using the answer code below.
(a) arteries (b) arterioles (c) capillaries (d) veins (e) lymphatics
_____ Site of exchange of nutrients and waste products between the blood and surrounding tissues.
_____ Serve as low-resistance passageways from the heart to the tissues.
_____ Serve as a blood reservoir to accommodate variations in blood volume.
_____ Major resistive vessels.
_____ Portion of the circulatory system through which the velocity of blood flow is the slowest.
_____ Serve as low-resistance passageways from the tissues to the heart.
_____ Act as a pressure reservoir to drive blood forward throughout the vasculature during cardiac diastole.
_____ Changes in the radius of this vessel type regulate the distribution of the cardiac output to various areas of the body.
_____ Vessels that pick up fluid that is filtered but not reabsorbed.
ANSWER: c, a, d, b, c, d, a, b, e
194.Indicate what effect the changes in question would have on blood flow, using the following answer code:
(a) This change would increase blood flow. (b) This change would decrease blood flow. (c) This change would have no effect on blood flow.
_____ Increasing the pressure gradient in a vessel. _____ Increasing the resistance of a vessel. _____ Increasing the radius of a vessel. _____ Increasing the number of circulating red
blood cells.
_____ Increasing the length of a vessel.
ANSWER: a, b, a, b, b
195.If the blood pressure is recorded as 118/76, indicate the correct value of the pressure in question by writing the appropriate letter in the blank using the following answer code: (a) 118 mm Hg
(b) 42 mm Hg (c) 97 mm Hg (d) 76 mm Hg (e) 90 mm Hg
_____ What is the systolic pressure? _____ What is the diastolic pressure? _____ What is the pulse pressure? _____ What is the mean pressure?
ANSWER: a, d, b, e
196.Match term with correct characteristic. (a) react hyperemia
(b) active hyperemia (c) pressure autoregulation (d) extrinsic control
_____ arteriolar dilation that occurs within a tissue in response to local chemical changes that accompany increased metabolic activity of the tissue.
_____ important in maintaining an adequate pressure head to drive blood forward to the tissues. _____ local arteriolar mechanisms that are aimed at
keeping tissue blood flow fairly constant in spite of rather wide deviations in mean arterial driving pressure.
_____ iIncrease in blood flow to a tissue that occurs after removal of an occlusion of its blood supply.
197.Indicate what effect the change in question would have on bulk flow using the answer code below: (a) The change would increase ultrafiltration and decrease reabsorption.
(b) The change would decrease ultrafiltration and increase reabsorption.
(c) The change would increase both ultrafiltration and reabsorption.
(d) the change would decrease both ultrafiltration and reabsorption.
(e) The change would not alter ultrafiltration and reabsorption.
_____ loss of plasma protein in the urine due to kidney disease
_____ rise in capillary blood pressure in connection with congestive heart failure
_____ loss of plasma volume due to hemorrhage _____ escape of plasma proteins into the interstitial
fluid due to capillary damage
_____ reduced synthesis of plasma proteins due to liver disease
_____ expanded plasma volume due to excessive fluid intake
ANSWER: a, a, b, a, a, a
198.Indicate whether arteriolar vasoconstriction or vasodilation would occur in the tissue in question by using the following answer code:
(a) would produce arteriolar vasoconstriction (b) would produce arteriolar vasodilation (c) would not cause any change in arteriolar caliber
_____ decreased O2 in skeletal muscle
_____ a hyperemic response in the heart _____ histamine release in an injured tissue _____ application of ice to a sprained ankle _____ occlusion of an artery supplying a particular
tissue
_____ norepinephrine on cerebral arterioles _____ sympathetic stimulation of kidney arterioles _____ parasympathetic discharge on skeletal muscle
arterioles
_____ increased stretch of arterioles supplying a particular tissue
ANSWER: b, b, b, a, b, c, a, c, a
Identifying Relationships
199.Indicate the relative comparison of each of the paired items by writing the appropriate letter in the blank using the following answer code: (a) A is greater than B.
(b) B is greater than A. (c) A and B are equal.
_____ A. blood flow through an arteriole upon increased sympathetic activity.
B. blood flow through an arteriole upon decreased sympathetic activity.
_____ A. blood flow through a vein upon increased sympathetic activity.
B. blood flow through a vein upon decreased sympathetic activity.
_____ A. velocity of blood flow through the veins. B. velocity of blood flow through the capillaries.
_____ A. local arteriolar radius in the presence of local decreased O2 concentration and
increased CO2 concentration.
B. local arteriolar radius with normal local concentration of O2 and CO2.
_____ A. circulation through the skin during exercise.
B. circulation through the skin at rest.
_____ A. circulation to the brain at rest. B. circulation to the brain during an examination.
_____ A. net ultrafiltration pressure at the arteriolar end of the capillary.
B. net reabsorption pressure at the venous end of the capillary.
200.When blood pressure falls below normal, indicate what happens to each of the following factors to restore the blood pressure back toward normal.
I. When the blood pressure falls below normal, the rate of firing in the afferent nerves originating from the carotid-sinus and aortic-arch baroreceptors:
(a) increases. (b) decreases. (c) does not change.
II. As a result of I, the medullary cardiovascular center responds by _____________ the rate of firing in the sympathetic cardiac nerve. (a) increasing
(b) decreasing (c) not changing
III. Also as a result of I, the cardiovascular center __________ the rate of firing in the
parasympathetic nerve supply to the heart. (a) increases
(b) decreases (c) does not alter
IV. Also as a result of I, the rate of firing in the sympathetic vasoconstrictor nerve __________ by the cardiovascular center.
(a) is increased (b) is decreased (c) is not altered
V. As a result of II and III, the rate of firing of the SA node:
(a) increases. (b) decreases.
(c) remains unchanged.
VI. As a result of V, the heart rate: (a) increases.
(b) decreases.
(c) remains unchanged.
VII. As a result of IV:
(a) Arteriolar vasoconstriction occurs. (b) Arteriolar vasodilation occurs. (c) There is no change in arteriolar radius.
VIII. As a result of VII, total peripheral resistance: (a) increases.
(b) decreases.
(c) remains unchanged.
IX. Also as a result of IV:
(a) Venous vasoconstriction occurs. (b) Venous vasodilation occurs. (c) There is no change in venous radius.
X. As a result of IX, venous return: (a) increases.
(b) decreases.
(c) remains unchanged.
XI. As a result of X, end-diastolic volume: (a) increases.
(b) decreases.
(c) remains unchanged.
XII. As a result of II and XI, stroke volume: (a) increases.
(b) decreases.
(c) remains unchanged.
XIII. As a result of VI and XII, cardiac output: (a) increases.
(b) decreases.
(c) remains unchanged.
XIV. As a result of VIII and XIII, blood pressure: (a) increases to normal.
(b) decreases to normal. (c) remains unchanged.
ANSWER: b, a, b, a, a, a, a, a, a, a, a, a, a, a
For questions 201-223, choose the appropriate letter from the answer code below to make the statement true.
(a) stimulates or increases (b) decreases or inhibits (c) has no effect on
201.Decreased rate of firing in afferent nerves reaching the cardiovascular control center ________ the parasympathetic nerve activity to the cardiovascular system.
ANSWER: b
202.Decreased rate of firing in afferent nerves reaching the cardiovascular control center ________ the sympathetic nerve activity to the cardiovascular system.
203.Increased parasympathetic nerve activity _____ the strength of cardiac ventricular contraction.
ANSWER: c
204.Increased sympathetic nerve activity _________ the rate of depolarization of the SA node.
ANSWER: a
205.Increased sympathetic nerve activity _________ the strength of cardiac ventricular contraction.
ANSWER: a
206.Increased sympathetic nerve activity _____ the stroke volume.
ANSWER: a
207.Increased parasympathetic nerve activity _________ the heart rate.
ANSWER: b
208.Increased heart rate _________ cardiac output.
ANSWER: a
209.Decreased stroke volume _______ cardiac output.
ANSWER: b
210.Decreased stroke volume _________ heart rate.
ANSWER: c
211.Decreased sympathetic nerve activity ________ the arteriolar radius.
ANSWER: a
212.Increased arteriolar radius ___________ the total peripheral resistance.
ANSWER: b
213.Increased total peripheral resistance _________ the mean systemic arterial blood pressure.
ANSWER: a
214.Decreased cardiac output _____________ the mean systemic arterial blood pressure.
ANSWER: b
215.Increased skeletal muscle activity _________ venous return.
ANSWER: a
216.Decreased O2, increased CO2, increased acid, and
increased K+ concentrations in a skeletal muscle
__________ the radius of the arterioles supplying this skeletal muscle.
ANSWER: a
217.Increased sympathetic nerve activity _________ the venous radius.
ANSWER: b
218.Decreased venous radius __________ the venous return.
ANSWER: a
219.Increased venous return _________ the end-diastolic volume.
ANSWER: a
220.Decreased venous return _________ the stroke volume.
ANSWER: b
221.Decreased arteriolar radius __________ the blood flow through the arteriole.
ANSWER: b
222.Increased venous radius __________ the blood flow through the vein.
ANSWER: b
223.Decreased parasympathetic nerve activity __________ total peripheral resistance.
224.Indicate whether the following would (a) increase BP
(b) decrease BP
(c) increase heart rate only
(d) have no effect on BP or heart rate
_____ increased vasomotor center activity _____ baroreceptors inhibited
_____ chemoreceptors activated _____ stress
_____ increased release of aldosterone _____ increased release of vasopressin _____ release of renin
_____ facultative Na+ reabsorption
_____ adrenalin release _____ venous vasodilation
ANSWER: a, a, a, a, a, a, a, a, a, b
Essay Questions
1. Describe how blood pressure is regulated.
2. Describe capillary filtration and reabsorption.
3. What hemodynamic changes occur when an individual goes from a resting state to an active state?
4. What are the roles of the lymphatic system in relation to the cardiovascular system.
5. How is salt balance tied into blood pressure control?
