019 Chapter 19

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					                                                  Chapter 19
                Student: _________________________________________________________

1. Contraction of any heart chamber is called ___.

2. A persistent, resting heart rate in excess of 100 beats/minute is called ___.

3. If the SA node fails to function, other regions of atrial myocardium called ___ take over and trigger a
rhythmic heartbeat, although at a slower rate.

4. When the ventricles first begin to contract, there is not enough pressure in them to force the semilunar valves
open, and for a moment, no blood is expelled. Therefore this phase of the cardiac cycle is called ___.

5. Each ventricle ejects about 75 ml of blood in one beat. This figure is called the ___.

6. The ventricles are said to exhibit ___ when they beat in a rapid, uncoordinated fashion and do not effectively
eject blood.

7. The death of a patch of myocardium due to ischemia is clinically known as ___ and likely to cause a heart

8. In the aortic arch and carotid arteries there are pressure sensors called ___, which help to monitor and
regulate blood pressure.

9. Cardiac output is a product of ___ and ___.

10. Gradual depolarization of cells of the SA node, prior to the point where membrane voltage reaches the
threshold, is called the ___ potential.

11. An increased afterload reduces the heart's ejection fraction.
True False

12. If the SA node is destroyed, the heart will stop beating.
True False

13. The first heart sound occurs at the same time as the P wave of the ECG.
True False

14. Being larger than the right ventricle, the left ventricle pumps more blood in each beat.
True False
15. The myocardium begins to relax at the end of the plateau in the action potential.
True False

16. Since athletes are in better than average condition, their hearts beat faster at rest.
True False

17. Cor pulmonale results when the left ventricle fails, causing blood to back up into the lungs.
True False

18. Cells of the SA node exhibit a long plateau in their action potentials.
True False

19. The parasympathetic nervous system has a negative chronotropic effect on the heart.
True False

20. The bundle of His originates at the AV node.
True False

21. The unusually long refractory period of the myocardium prevents wave summation and tetanic contraction.
True False

22. Papillary muscles help to prevent prolapse of the semilunar valves.
True False

23. The myocardium receives the least amount of blood when the ventricles are contracting.
True False

24. The resting heart rate would be slower if not for the fact that sympathetic nerve fibers continually stimulate
True False

25. Most blood enters the ventricles even before the atria begin to contract.
True False

 Match the following terms to the definitions.
afterload                    AV bundle
bradycardia                  cardiac output
chordae tendineae            circumflex artery
coronary sinus               endocardium
epicardium                   first heart sound
left atrium                  mitral valve prolapse
preload                      pulmonary arteries
pulmonary veins              second heart sound
stroke volume                superior vena cava
tachycardia                  ventricular diastole
ventricular systole

26. This is the same as the visceral pericardium.
27. This helps to prevent valvular prolapse during ventricular systole.

28. Empties into the right atrium ::

29. Site of damage that could cause heart block.

30. Phase of the cardiac cycle in which the AV valves close.

31. This is caused partly by closing of the semilunar valves ________.

32. This receives blood that has circulated through the myocardium.

33. Milliliters of blood ejected by one beat of the left ventricle is known as ________.

34. Abnormally fast heart rate is known as ________.

35. End-diastolic volume is known as ________.

36. The coronary arteries arise from
A. the proximal end of the aorta.
B. the interventricular arteries.
C. the myocardium.
D. the coronary sulcus.
E. the venae cavae.

37. In the action potential of a myocardial cell, the Ca 2+ gates close
A. when the pacemaker potential reaches threshold.
B. when the voltage reaches its highest positive value.
C. just as the cell begins to depolarize.
D. at the end of the voltage plateau.
E. at the end of repolarization.

38. If the electrocardiogram exhibits a nodal rhythm
A. the heart is functioning normally.
B. the heart is beating at a slow rate set by the AV node.
C. the heart is beating at a fast rate set by the SA node.
D. the heart is in ventricular fibrillation.
E. there is probably a bundle branch block.

39. The average resting cardiac cycle takes about 0.8 sec, including 0.1 sec for atrial systole, 0.3 sec for
ventricular systole, and 0.4 sec for
A. isovolumetric relaxation.
B. ventricular diastole.
C. atrial diastole.
D. cardiac reserve.
E. the quiescent period.

40. If the heart's normal pacemaker is nonfunctional and the AV node takes over, the heart beats at a rate of 40-
60 bpm called
A. the endogenous rhythm.
B. the chronotropic rhythm.
C. the ectopic rhythm.
D. the sinus rhythm.
E. the nodal rhythm.

41. If the chordae tendineae of an animal's heart were cut, the most likely effect would be
A. valvular stenosis.
B. valvular prolapse.
C. fibrillation.
D. heart block.
E. myocardial infarction.

42. Blood normally leaves the right ventricle through
A. the pulmonary semilunar valve.
B. the pulmonary tricuspid valve.
C. the tricuspid valve.
D. the bicuspid valve.
E. the aortic semilunar valve.

43. A heart rate of 45 bpm and an absence of P waves from the electrocardiogram would suggest
A. ventricular fibrillation.
B. cardiac arrhythmia.
C. a bundle branch block.
D. cor pulmonale.
E. damage to the SA node.

44. The fast-rising phase of the SA node action potential is due to
A. the opening of slow calcium channels.
B. the closing of potassium channels.
C. calcium influx.
D. potassium influx.
E. potassium efflux.

45. A friction rub results from
A. a myocardial infarction.
B. ventricular fibrillation.
C. valvular insufficiency.
D. an excessive afterload.
E. a deficiency of pericardial fluid.

46. The electrical synchrony of the ventricular myocardium results from
A. the gap junctions of the intercalated discs.
B. the desmosomes of the intercalated discs.
C. the simultaneous firing of the SA and AV nodes.
D. the internodal pathways.
E. the fibrous skeleton.

47. The amount of blood (mL) coming from one ventricle in one heartbeat is called
A. the ejection fraction.
B. the preload.
C. the afterload.
D. the stroke volume.
E. the cardiac output.

48. Atrial systole begins
A. immediately before the P wave.
B. immediately after the P wave.
C. during the Q wave.
D. during the S-T segment.
E. immediately after the T wave.

49. Diastasis is a period of
A. atrial systole.
B. isovolumetric relaxation.
C. slow ventricular filling.
D. reduced ejection.
E. rapid ejection.

50. The cardiac center, which modifies the heart rate, is located in
A. the SA node.
B. the AV node.
C. the carotid sinuses.
D. the aortic arch.
E. the medulla oblongata.

51. The cardioinhibitory center communicates with the heart by way of
A. the internodal pathways.
B. the bundle of His.
C. Purkinje fibers.
D. the vagus nerves.
E. sympathetic nerves.

52. At the end of ventricular contraction, the amount of blood remaining in the ventricle is
A. the end-systolic volume.
B. the end-diastolic volume.
C. the stroke volume.
D. the residual volume.
E. the ejection fraction.

53. The heart's normal ___ of 54% can rise to as high as 90% during strenuous exercise.
A. ejection fraction
B. end-systolic volume
C. end-diastolic volume
D. coronary circulation
E. stroke volume

54. Pressure in the arteries that opposes the opening of the semilunar valves is called
A. inotropic pressure.
B. oncotic pressure.
C. afterload.
D. preload.
E. hypertension.

55. The second heart sound immediately follows
A. closing of the AV valves.
B. the end of diastole.
C. the P wave.
D. the QRS complex.
E. the T wave.

56. The heart rate tends to be higher in
A. women than in men.
B. teenagers than in infants.
C. athletes than in sedentary people.
D. men than in women.
E. adults than in children.

57. The ___ commonly measures about 75 mL.
A. cardiac output
B. stroke volume
C. end-diastolic volume
D. end-systolic volume
E. ejection fraction

58. The conduction of electrical signals is fastest in
A. the atria.
B. the internodal pathways.
C. the Purkinje fibers.
D. the SA node.
E. the AV node.

59. One way of stating the Frank-Starling law of the heart is that stroke volume is proportional to
A. the end-systolic volume.
B. the end-diastolic volume.
C. the afterload.
D. the heart rate.
E. contractility.

60. Baroreceptors are located in
A. the aorta and carotid sinuses.
B. the superior and inferior venae cavae.
C. the internal carotid arteries only.
D. the internal and external jugular veins.
E. the circulatory system pressure points.

61. If end-diastolic volume is 108 mL, end-systolic volume is 35 mL, and ejection fraction is 0.86, then the
stroke volume must be
A. 0.03 L.
B. 0.086 L.
C. 73 mL.
D. 138 mL.
E. 143 mL.

62. During isovolumetric contraction, the pressure in the ventricles
A. rises rapidly.
B. falls rapidly.
C. remains constant.
D. rises and then falls.
E. falls and then rises.

63. Isovolumetric contraction occurs during the ___ of the electrocardiogram.
A. P wave
B. P-Q segment
C. S-T segment
D. R wave
E. T wave

64. Hypercapnia has the effect of
A. increasing the heart rate.
B. decreasing the heart rate.
C. increasing myocardial contractility.
D. increasing the afterload.
E. reducing the ejection fraction.

65. The effect of vagal tone on the heart is to
A. prolong the plateau in the action potential.
B. hyperpolarize the SA node.
C. shorten the pacemaker potential.
D. reduce conduction speed through the AV node.
E. inhibit the breakdown of cAMP.

66. The heart rate is increased by
A. hypothyroidism.
B. acetylcholine.
C. hyperkalemia.
D. hypernatremia.
E. hypercalcemia.

67. Lung diseases that obstruct the flow of blood through the lungs are most likely to
A. increase the preload in the left ventricle.
B. increase the afterload in the pulmonary trunk.
C. increase the ejection fraction of the right ventricle.
D. reduce the ejection fraction of the left ventricle.
E. have a positive chronotropic effect on both ventricles.

68. The innermost lining of the heart wall is
A. the parietal pericardium.
B. the visceral pericardium.
C. the epicardium.
D. the endocardium.
E. the myocardium.
69. An anatomical arrangement that reduces the risk for myocardial infarctions is
A. arterial anastomoses in the coronary circulation.
B. the desmosomes of the intercalated discs.
C. a double circulation.
D. gap junctions in the myocardium.
E. circumflex arteries.

70. Unlike skeletal muscle, cardiac muscle has
A. a more extensive sarcoplasmic reticulum.
B. more nuclei per cell.
C. more mitochondria.
D. longer fibers.
E. shorter refractory periods.

71. A substance that reduces the heart rate is said to exert
A. a positive inotropic effect.
B. a negative chronotropic effect.
C. a positive barotropic effect.
D. a negative inotropic effect.
E. a positive chemotropic effect.

72. Which of the following reduces the heart rate?
A. epinephrine
B. acetylcholine
C. norepinephrine
D. digitalis
E. nicotine

73. Because the human heart is myogenic
A. it will beat even if all nerves to it are severed.
B. both ventricles pump the same amount of blood.
C. it is not subject to the influence of hormones.
D. it contracts rhythmically.
E. it generates electrical activity that can be detected by an electrocardiograph.

74. Which of the following vessels are in the coronary sulcus?
A. the anterior and posterior interventricular arteries
B. the superior and inferior venae cavae
C. the great and middle cardiac veins
D. the right and left semilunar arteries
E. the marginal artery and circumflex artery

75. The cardiovascular system refers to all of the below except one. The area that is not part of the
cardiovascular system is the
A. heart.
B. arteries.
C. blood.
D. capillaries.
E. veins.
76. In the cardiovascular system, the _____ circuit carries blood to and from the lungs, which is served by the
_____ side of the heart.
A. pulmonary; left
B. systemic; left
C. pulmonary; right
D. systemic; right
E. coronary; right

77. Blood, which is _____, leaves the left side of the heart and is pumped into the _____.
A. O2 rich, CO2 poor; aorta
B. O2 poor, CO 2 rich; pulmonary artery
C. O2 rich, CO2 poor; pulmonary vein
D. O2 poor, CO2 rich; vena cavas
E. O2 rich, CO2 poor; pulmonary capillaries

78. The heart is enclosed in a double-walled sac called the pericardium. The outer wall is called the _____
pericardium and consists of
A. parietal; fibrous and serous layers.
B. parietal; a serous layer.
C. visceral; fibrous and serous layers.
D. visceral; a serous layer.
E. visceral; a fibrous layer.

79. The endocardium is lined by a _____ epithelium called the _____.
A. simple squamous; mesothelium
B. simple squamous; endothelium
C. simple cuboidal; mesothelium
D. stratified squamous; endothelium
E. stratified sqamous; mesothelium

80. The myocardia of the two atria are simultaneously excited, but the atria do not stimulate the ventricles
directly, otherwise all of the chambers of the heart would contract at the same time. The signals from the atria
are blocked from stimulating the ventricles directly by the
A. interventricular sulcus.
B. interventricular septum.
C. fibrous skeleton.
D. conduction system.
E. SA node.

81. The internal ridges in the atria are called _____, while the internal ridges in the ventricles are called _____.
A. papillary muscles; pectinate muscles
B. pectinate muscles; trabeculae carneae
C. pectinate muscles; papillary muscles
D. trabeculae carneae; chordae tendineae
E. papillary muscles; chordae tendineae

82. When the left ventricle contracts the _____ valve closes and the _____ valve is pushed open.
A. bicuspid; pulmonary
B. tricuspid; aortic
C. mitral; aortic
D. tricuspid; pulmonary
E. bicuspid; pulmonary
83. When the ventricles contract, the papillary muscles also contract, which
A. tightens the chordae tendineae preventing the AV valves from prolapsing.
B. tightens the chordae tendineae, causing the AV valves to close.
C. loosens the chordae tendineae, allowing the semilunar valves to open.
D. loosens the chordae tendineae, allowing the semilunar valves to close.
E. loosens the chordae tendineae, causing the AV valves to open.

84. In mitral stenosis, one of the most common forms of valvular heart disease, when the ventricles contract
blood will leak back into the
A. left atrium.
B. right atrium.
C. aorta.
D. pulmonary trunk.
E. pulmonary arteries.

85. You are following the pathway of blood from the superior vena cava to the aorta. What is the correct order
of valves through which the blood will pass?
A. aortic, bicuspid, pulmonary, tricuspid
B. tricuspid, aortic, bicuspid, pulmonary
C. tricuspid, pulmonary, bicuspid, aortic
D. pulmonary, bicuspid, aortic, tricuspid
E. bicuspid; pulmonary; tricuspid; aortic

86. The coronary artery receives blood from the ____, and the coronary artery empties blood into the _____.
A. pulmonary artery; right atrium
B. superior vena cava; left atrium
C. inferior vena cava; left atrium
D. aorta; right atrium
E. pulmonary vein; right atrium

87. The left coronary artery divides into the
A. marginal and posterior interventricular arteries.
B. anterior interventricular and circumflex arteries.
C. marginal and circumflex arteries.
D. anterior and posterior interventricular arteries.
E. posterior interventricular and marginal arteries.

88. An individual is feeling severe chest pain, which radiates to the neck, jaw, shoulder, and left arm. The
individual is showing symptoms of
A. tachycardia.
B. myocardial infarction.
C. congestive heart failure.
D. valvular heart disease.
E. bradycardia.

89. Cardiac muscle metabolism is different from skeletal muscle metabolism because cardiac muscle
A. can break down fatty acids for energy.
B. relies more on anaerobic respiration.
C. does not rely on anaerobic respiration.
D. is more prone to fatigue.
E. produces more lactic acid.
90. Which one of the following parts of the conduction system directly stimulates the ventricles?
A. AV node
B. AV bundle
C. right and left bundle branches
D. Purkinje fibers
E. bundle of His

91. Acetylcholine binds to muscarinic receptors on the SA node causing a K + leak. This will cause the heart to
A. slow its rate of contraction.
B. speed up its rate of contraction.
C. fibrillate.
D. stop beating.
E. have nodal rhythm.

92. Hypocalcaemia will cause the heart rate to _____ and hyperkalemia will cause heart rate to _____.
A. increase; increase
B. decrease; decrease
C. increase; decrease
D. decrease; increase
E. increase; stop

93. The absolute refractory period in the myocyte results in
A. stimulation of neighboring myocytes.
B. continual production of action potentials called pacemaker potentials.
C. the ability to wave summate and to undergo tetany.
D. the prevention of wave summation and tetanus.
E. the ability to use glucose in anaerobic glycolysis.

94. An individual has mitral valve prolapse, which generates a gurgling sound called a heart murmur. The
murmur would be associated with the _____ heart sound and occurs when the ____.
A. lubb (S1); atria contract
B. dupp (S2); atria relax
C. lubb (S1); ventricles contract
D. dupp (S2); ventricles relax
E. lubb (S1); ventricles relax

95. The aortic semilunar valve shuts when the pressure in the aorta is ______ and results in the _____ heart
A. less than in the left ventricle; dupp (S2)
B. less than in the right ventricle lubb (S1)
C. greater than in the left ventricle; dupp (S2)
D. greater than in the left ventricle; lubb (S1)
E. greater than in the right ventricle; dupp (S2)

96. The mitral, or bicuspid valve, opens when the pressure in the left ventricle is _____; and the mitral valve
closes when the pressure in the left ventricle is _____.
A. less than the pressure in the left atrium; greater than the pressure in the left atrium
B. less than the pressure in the aorta; greater than the pressure in the aorta
C. less than the pressure in the right atrium; greater than the pressure in the right atrium
D. less than the pressure in the pulmonary trunk; greater than the pressure in the pulmonary trunk.
E. greater than the pressure in the left atrium; less than the pressure in the left atrium.
97. Blood moves into the aorta when the pressure in the aorta is ____ causing the aortic valve to ____.
A. less than the pressure in the right ventricle; close
B. greater than the pressure in the right ventricle; open
C. greater than the pressure in the left ventricle; close
D. less than the pressure in the left ventricle; open
E. the same as the pressure in the left ventricle; open

98. Most of the ventricle filling occurs
A. during atrial systole.
B. during atrial diastole.
C. during ventricular systole.
D. isovolumetric contraction.
E. when the AV valve is closed.

99. The first heart sound (S1 or lubb) is primarily caused by ________.
A. left ventricle contracting
B. left atrium contracting
C. right ventricle relaxing
D. right atrium relaxing
E. left atrium relaxing

100. The pressure peaks at about ____ mmHg in the left ventricle and at about _____ mmHg in the right
A. 25; 120
B. 80; 120
C. 120; 25
D. 120; 80
E. 140; 90
                               Chapter 19 KEY
1. systole
2. tachycardia
3. ectopic pacemakers
4. isovolumetric contraction
5. stroke volume
6. fibrillation
7. myocardial infarction
8. baroreceptors
9. heart rate; stroke volume
10. pacemaker
11. TRUE
15. TRUE
19. TRUE
20. TRUE
21. TRUE
23. TRUE
25. TRUE
26. epicardium
27. chordae tendineae
28. superior vena cava
29. AV bundle
30. ventricular systole
31. second heart sound
32. coronary sinus
33. stroke volume
34. tachycardia
35. preload
36. A
37. D
38. B
39. E
40. E
41. B
42. A
43. E
44. C
45. E
46. A
47. D
48. B
49. C
50. E
51. D
52. A
53. A
54. C
55. E
56. A
57. B
58. C
59. B
60. A
61. C
62. A
63. D
64. A
65. B
66. E
67. B
68. D
69. A
70. C
71. B
72. B
73. A
74. E
75. C
76. C
77. A
78. A
79. B
80. C
81. B
82. C
83. A
84. A
85. C
86. D
87. B
88. B
89. C
90. D
91. A
92. C
93. D
94. C
95. C
96. A
97. D
98. B
99. A
100. C

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