Chapter 27 Fluid, Electrolyte, and Acid-Base Balance

1. The right side of the heart receives blood from the body and pumps through _________ circulation to the lungs.

A. hepatic

B. pulmonary

C. peripheral

D. systemic

B. pulmonary

2. The delivery of oxygen and nutrients to the tissues of the body is accomplished through ________ circulation.

A. hepatic

B. pulmonary

C. peripheral

D. systemic

D. systemic

3. Which of the following is NOT a function of the heart?

A. providing a location for gas exchange between oxygen and carbon dioxide

B. regulating blood supply to tissues depending on need

C. generating blood pressure through contraction

D. routing blood to either the pulmonary or systemic circulations

A. providing a location for gas exchange between oxygen and carbon dioxide

4. Which of the following is NOT true about the heart?

A. The heart is about the size of a closed fist.

B. The heart is located in the mediastinum.

C. The apex of the heart is directed superiorly and to the left.

D. Knowing the heart's position is important for effective CPR.

C. The apex of the heart is directed superiorly and to the left.

5. The heart

A. is a four-chambered muscular pump.

B. is posterior to the trachea.

C. is lined with an epithelial layer called epicardium.

D. lies mostly to the right of the midline of the sternum.

E. has a superior apex and an inferior base.

A. is a four-chambered muscular pump.

6. The pericardial sac is lined with

A. fibrous pericardium.

B. parietal pericardium.

C. visceral pericardium.

D. myocardium.

E. epicardium.

B. parietal pericardium.

7. The epicardium

A. covers the surface of the heart.

B. lines the walls of the ventricles.

C. is known as the fibrous pericardium.

D. attaches inferiorly to the diaphragm.

E. is also called endocardium.

A. covers the surface of the heart.

8. A serious condition in which a large amount of fluid accumulates in the pericardial cavity and puts pressure of the heart is

A. endocarditis.

B. pericarditis.

C. a myocardial infarction.

D. cardiac tamponade.

D. cardiac tamponade.

9. E.Z. Goen is admitted to the cardiac unit with a diagnosis of endocarditis. When E.Z. asks the nurse where the infection is located, the nurse replies that the infection is in

A. the outer layer of the heart wall.

B. the inner lining of the heart.

C. a membranous sac that encloses the heart wall.

D. the muscular layer of the heart.

E. the lining of the mediastinum.

B. the inner lining of the heart.

10. Another name for the visceral pericardium is the

A. endocardium.

B. epicardium.

C. isocardium.

D. myocardium.

E. visocardium.

B. epicardium.

11. Which of the following pairs is mismatched?

A. endocardium - covers the inner surfaces of the heart

B. myocardium - cardiac muscle

C. trabeculae carneae - interior walls of ventricles

D. pectinate muscles - muscles that close valves

E. chordae tendineae - connective tissue strings that connect to cusps of valves

D. pectinate muscles - muscles that close valves

12. A stab wound into the heart can result in cardiac tamponade. This means that

A. blood enters the pleural cavity.

B. the heart is compressed by blood in the pericardial sac.

C. the electrical conduction system of the heart is damaged.

D. the left coronary artery has been damaged or cut.

E. the heart has lost all of its blood.

B. the heart is compressed by blood in the pericardial sac.

13. Which of the following layers forms the bulk of the heart wall?

A. epicardium

B. pericardium

C. endocardium

D. myocardium

E. visceral pericardium

D. myocardium

14. The function of the pericardial fluid is to

A. reduce friction between the pericardial membranes.

B. lubricate the heart valves.

C. replace any blood that is lost.

D. provide oxygen and nutrients to the endocardium.

E. stimulate the heart.

A. reduce friction between the pericardial membranes.

15. Blood vessels enter and exit from the _____ of the heart.

A. apex

B. base

C. auricles

D. trigone

E. inferior aspect

B. base

16. Blood in the pulmonary veins returns to the

A. right atrium.

B. left atrium.

C. right ventricle.

D. left ventricle.

E. coronary sinus.

B. left atrium.

17. The great cardiac vein and middle cardiac vein empty into a venous cavity called the

A. pulmonary vein.

B. inferior vena cava.

C. superior vena cava.

D. coronary sinus.

E. coronary artery.

D. coronary sinus.

18. All cardiac veins empty into the _________, which then empties into the _______.

A. coronary sinus; left atrium

B. coronary sinus; right atrium

C. great cardiac vein; right atrium

D. great cardiac vein; superior vena cava

E. inferior vena cava; left atrium

B. coronary sinus; right atrium

19. Occlusion of which of the following would primarily damage the posterior wall of the heart?

A. circumflex artery

B. pulmonary artery

C. right marginal artery

D. coronary sinus artery

E. right coronary artery

A. circumflex artery

20. Which of these statements is true?

A. The left coronary artery is a branch of the left pulmonary vein.

B. The coronary sinus returns blood to the left atrium.

C. The coronary arteries arise from the pulmonary trunk.

D. The great cardiac vein collects blood from the left anterior surface of the heart.

E. The pulmonary arteries carry blood to the left atrium.

D. The great cardiac vein collects blood from the left anterior surface of the heart.

21. A direct connection between arteries is called a/an

A. auricle.

B. sulcus.

C. sinus.

D. anastamosis.

D. anastamosis.

22. Blood flow through the coronary blood vessels decreases during myocardial contraction and increases during myocardial relaxation.

A. true

B. false

A. true

23. Coronary artery disease can diminish myocardial blood flow resulting in the death of myocardial cells. This condition is known as a myocardial

A. attack.

B. angina.

C. necrosis.

D. cirrhosis.

E. infarction.

E. infarction.

24. The procedure whereby a small balloon is placed into a partially occluded coronary artery and then inflated to increase blood flow through the artery is called a(n)

A. angioplasty.

B. coronary bypass.

C. urokinase injection.

D. tissue plasminogen activation.

E. angiogram.

A. angioplasty.

25. Angina pectoris is chest pain caused by reduced

A. stimulation of the myocardium.

B. blood supply to cardiac muscle.

C. fluid in the pericardial sac.

D. contractility of the heart.

E. action potentials from SA node.

B. blood supply to cardiac muscle.

26. Which of the following is NOT an enzyme given to someone experiencing a myocardial infarction to break up blood clots?

A. streptokinase

B. tissue plasminogen activator (t-Pa)

C. nitroglycerin

D. urokinase

C. nitroglycerin

27. Which of the following is NOT a major opening into the right atrium?

A. pulmonary vein

B. inferior vena cava

C. superior vena cava

D. coronary sinus

A. pulmonary vein

28. The right atrium receives blood from

A. the lungs and the heart.

B. the heart.

C. the body and the heart.

D. the lungs and the body.

C. the body and the heart.

29. What is the foramen ovale?

A. An opening between the right and left atria in the embryo and fetus.

B. An opening between the right and left ventricles in the embryo and fetus.

C. An oval hole in the pericardium in the embryo and fetus.

D. An opening between the pulmonary trunk and aorta in the embryo and fetus.

A. An opening between the right and left atria in the embryo and fetus.

30. What vessel exits the left ventricle?

A. pulmonary trunk

B. pulmonary vein

C. aorta

D. pulmonary artery

C. aorta

31. The AV valve that is located on the same side of the heart as the origin of the aorta is the

A. bicuspid or mitral valve.

B. tricuspid valve.

C. aortic semilunar valve.

D. pulmonary semilunar valve.

E. coronary sinus valve.

A. bicuspid or mitral valve.

32. The valve located between the right ventricle and the pulmonary trunk is the

A. aortic semilunar valve.

B. pulmonary semilunar valve.

C. tricuspid valve.

D. mitral valve.

E. bicuspid valve.

B. pulmonary semilunar valve.

33. Contraction of the papillary muscles would

A. eject blood from the ventricles.

B. prevent the AV valves from protruding into the atria.

C. close the semilunar valves.

D. cause the atria to eject their contents into the ventricles.

E. open the semilunar valves.

B. prevent the AV valves from protruding into the atria.

34. The chordae tendineae

A. connect the atria to the ventricles.

B. are found in the interventricular septum.

C. are part of the conducting system of the heart.

D. connect the flaps of the AV valves to the papillary muscles.

E. are a part of the myocardium.

D. connect the flaps of the AV valves to the papillary muscles.

35. Blood in the superior vena cava will enter the _____.

A. aorta

B. right atrium

C. pulmonary trunk

D. pulmonary arteries

E. pulmonary veins

B. right atrium

36. Which vessels empty blood into the left atrium?

A. aorta

B. right atrium

C. pulmonary trunk

D. pulmonary arteries

E. pulmonary veins

E. pulmonary veins

37. Which blood vessel carries blood from the left ventricle?

A. aorta

B. right atrium

C. pulmonary trunk

D. pulmonary arteries

E. pulmonary veins

A. aorta

38. From the right ventricle, blood flows directly into the _____.

A. aorta

B. right atrium

C. pulmonary trunk

D. pulmonary arteries

E. pulmonary veins

C. pulmonary trunk

39. Which vessels transport blood to the right and left lungs?

A. aorta

B. right atrium

C. pulmonary trunk

D. pulmonary arteries

E. pulmonary veins

D. pulmonary arteries

40. An incompetent pulmonary semilunar valve could result in less blood reaching the

A. lungs.

B. heart muscle.

C. right ventricle.

D. aorta.

E. right atrium.

A. lungs.

41. Which of the following heart chambers is correctly associated with the blood vessel that enters or leaves it?

A. right atrium - pulmonary veins

B. left atrium - aorta

C. right ventricle - pulmonary trunk

D. left ventricle - superior vena cava and inferior vena cava

E. right atrium - aorta

C. right ventricle - pulmonary trunk

42. Which of the following is a function of the heart skeleton?

A. Provides electrical insulation between the atria and ventricles.

B. Supplies support and reinforcement for the valves.

C. Provides a rigid site for cardiac muscle attachment.

D. All of the choices are functions of the heart skeleton.

D. All of the choices are functions of the heart skeleton.

43. Cardiac muscle cells

A. have smooth ER but no T tubules.

B. form the heart valves.

C. are maintained by an extensive capillary network.

D. develop a significant oxygen debt during systole.

E. do not contain actin and myosin like skeletal muscle cells.

C. are maintained by an extensive capillary network.

44. Which of the following phrases would apply to cardiac muscle cells?

A. are organized in parallel columns or bundles

B. contain actin but no myosin

C. develop a significant oxygen debt during systole

D. are multinucleated like skeletal muscle cells

E. possess special cell-to-cell contacts called intercalated discs

E. possess special cell-to-cell contacts called intercalated discs

45. Action potentials pass from one myocardial cell to another through areas of low electrical resistance called

A. gap junctions.

B. fibrous heart rings.

C. electromagnetic discs.

D. sarcolemma sclerotic plaques.

E. tight junctions.

A. gap junctions.

46. The "pacemaker" of the heart is the

A. right bundle branch.

B. left bundle branch.

C. AV node.

D. SAnode.

E. PM node.

D. SAnode.

47. Which of the following sequences for the conducting system is correct?

A. AV node, AV bundle, SA node, Purkinje fibers, bundle branches

B. Purkinje fibers, bundle branches, AV node, AV bundle, SA node

C. SA node, AV node, AV bundle, bundle branches, Purkinje fibers

D. SA node, AV bundle, AV node, bundle branches, Purkinje fibers

E. AV node, SA node, bundle branches, AV bundle, Purkinje fibers

C. SA node, AV node, AV bundle, bundle branches, Purkinje fibers

48. What is the importance of the delay in the action potential in the AV node?

A. It allows the action potential to reach both ventricles at the same time.

B. It allows an action potential to reach the left atrium so both atria contract together.

C. It slows the rate of contraction of the ventricles.

D. It allows time for the atria to be filled with blood.

B. It allows an action potential to reach the left atrium so both atria contract together.

49. Energy for contraction of myocardial cells comes primarily from

A. aerobic respiration in the mitochondria.

B. anaerobic respiration in the cytosol.

C. glycolysis in the cytosol.

D. ATP that is stored while the heart is not contracting.

E. creatine phosphate.

A. aerobic respiration in the mitochondria.

50. The cardiac electrical impulse normally begins spontaneously in the SA node because

A. of the superior location of the SA node in the right atrium.

B. the SA node is the only area of the heart capable of spontaneous depolarization.

C. of the rich sympathetic innervation of the SA node.

D. this area produces action potentials more rapidly than any other portion of the conduction system.

E. of action potentials from the cardioregulatory center.

D. this area produces action potentials more rapidly than any other portion of the conduction system.

51. Which of the following will depolarize immediately after the AV node depolarizes?

A. the AV bundle

B. Purkinje fibers

C. atrial myocardium

D. bundle branches in the ventricular septum

E. theSAnode

A. the AV bundle

52. Ventricular contraction begins at the

A. AV bundle.

B. apex of the heart.

C. base of the heart.

D. superior portion of the interventricular septum.

E. top of the ventricles.

B. apex of the heart.

53. The action potentials are slowed at the AV node to allow the

A. ventricles to repolarize.

B. ventricles to completely empty of blood.

C. pacemaker to reset for the next beat.

D. atria to complete their contraction.

E. atria to begin their contraction.

D. atria to complete their contraction.

54. The spontaneous opening of sodium channels marks the beginning of ____ of a myocardial cell.

A. depolarization

B. repolarization

C. hyperpolarization

D. isopolarization

E. afterpolarization

A. depolarization

55. The plateau phase seen during the action potential of a cardiac muscle cell is due to the

A. sodium-potassium pump.

B. opening of sodium channels.

C. continuing to have open calcium channels.

D. closure of chloride channels.

E. closing of calcium channels.

C. continuing to have open calcium channels.

56. When a pacemaker potential in the SA node reaches threshold,

A. the permeability to K+ ions increases.

B. many voltage-gated Ca2+ channels open.

C. voltage-gated Ca2+ channels close.

D. RMP has been restored.

E. permeability of the cell does not change.

B. many voltage-gated Ca2+ channels open.

57. If the SA node is nonfunctional, which of the following is most likely to occur?

A. The heart will go into asystole (stop).

B. Tachycardia will develop.

C. Another portion of the heart will become the pacemaker.

D. The heart will go into defibrillation.

E. The heart will be desensitized.

C. Another portion of the heart will become the pacemaker.

58. Which of the following events occurs first?

A. threshold

B. depolarization

C. early repolarization

D. final repolarization

E. pacemaker potential

E. pacemaker potential

59. Calcium channel blockers are frequently used to

A. increase the heart rate.

B. treat tachycardia or other arrhythmias.

C. speed up conduction of impulses through the AV node.

D. slow the closing of potassium ion channels.

E. treat bradycardia and low blood pressure.

B. treat tachycardia or other arrhythmias.

60. Depolarization of a cardiac muscle cell occurs as the result of

A. a decrease in the permeability of the cell membrane to sodium.

B. the opening of voltage-gated sodium channels and voltage-gated calcium channels.

C. the closure of voltage-gated calcium channels.

D. the opening of voltage-gated potassium channels.

E. the closure of the voltage-gated sodium channels.

B. the opening of voltage-gated sodium channels and voltage-gated calcium channels.

61. When comparing cardiac muscle cells and skeletal muscle cells,

A. the rate of action potential propagation is faster in cardiac muscle.

B. both possess intercalated discs.

C. only skeletal muscle has a plateau phase in its contraction cycle.

D. action potentials are conducted from cell to cell only in cardiac muscle.

E. both are voluntary.

D. action potentials are conducted from cell to cell only in cardiac muscle.

62. What action is most responsible for the resting membrane potential in cardiac muscle cells?

A. movement of K+ through voltage-gated K+ channels

B. movement of Na+ through open Na+ channels

C. movement of Ca2+ through voltage-gated Ca2+ channels.

D. closing of Na+ and K+ voltage-gated channels

A. movement of K+ through voltage-gated K+ channels

63. Which of the following is mismatched?

A. opening of sodium channels - depolarization

B. closing of calcium channels - plateau phase

C. opening of potassium channels - rapid repolarization

D. closure of sodium channels - early repolarization

E. opening of calcium channels - plateau phase

B. closing of calcium channels - plateau phase

64. Which of the following would result from a reduced function of the sodium channels in the SA node?

A. depolarization would be delayed

B. the heart rate would decrease

C. repolarization would not occur

D. a shortened plateau phase

E. depolarization would be delayed and the heart rate would decrease

E. depolarization would be delayed and the heart rate would decrease

65. Which of the following areas of the conduction system would produce spontaneous action potentials most frequently if the SA node were not functioning?

A. AV bundle

B. Purkinje fibers

C. AV node

D. bundle branch

E. the pacemaker

C. AV node

66. The long refractory period observed in cardiac muscle

A. prolongs depolarization of the cardiac muscle.

B. prevents tetanic contractions of the cardiac muscle.

C. ensures that the heart has adequate time to contract.

D. prevents the heart rate from slowing down.

E. prevents an increase in heart rate.

B. prevents tetanic contractions of the cardiac muscle.

67. The period of time in which the myocardium is insensitive to further stimulation is called the

A. absolute refractory period.

B. hyperpolarization period.

C. AV period.

D. SAperiod.E. ectopic focus.

A. absolute refractory period.

68. If cardiac muscle cells are unable to repolarize, this would cause

A. cardiac output to increase.

B. no harm. These cells can spontaneously depolarize anyway.

C. the heart rate to decrease. It might cause cardiac arrest.

D. an increased demand on mitochondria to produce more ATP.

E. tachycardia.

C. the heart rate to decrease. It might cause cardiac arrest.

69. In a normal electrocardiogram, the

A. P wave results from repolarization of the atria.

B. QRS complex results from ventricular depolarization.

C. P wave occurs after the QRS complex but before the T wave.

D. T wave represents depolarization of the atria.

E. repolarization of the atria is clearly visible.

B. QRS complex results from ventricular depolarization.

70. The P wave of an ECG indicates

A. atrial depolarization.

B. atrial repolarization.

C. ventricular depolarization.

D. ventricular repolarization.

E. threshold.

A. atrial depolarization.

71. Of the types of damage resulting from a myocardial infarction, which is most likely to cause the greatest increase in the Q-T interval?

A. infarction in the AV node

B. left bundle branch block

C. infarction affecting the SA node

D. tachycardia

E. ectopic focus

B. left bundle branch block

72. What event(s) occur during the QRS complex of an ECG?

A. depolarization of the atria

B. repolarization of the ventricles

C. depolarization of the atria and repolarization of the ventricles

D. depolarization of the ventricles and repolarization of the atria

D. depolarization of the ventricles and repolarization of the atria

73. What abnormal heart rhythm could be caused by an elevated body temperature, excessive sympathetic stimulation, or toxic conditions?

A. bradycardia

B. atrial fibrillation

C. second-degreeAVnodeblock

D. tachycardia

D. tachycardia

74. What cardiac arrhythmia will have no QRS complex as a symptom?

A. atrial fibrillation

B. ventricular fibrillation

C. bradycardia

D. premature ventricular contractions

B. ventricular fibrillation

75. Variations in respiratory rate is a symptom of

A. sinus arrhythmia.

B. ventricular tachycardia.

C. SAnodeblock.

D. paroxysmal atrial tachycardia

A. sinus arrhythmia.

76. Contraction of the ventricles is referred to as ventricular

A. systole.

B. diastole.

C. fibrillation.

D. ischemia.

E. depolarization.

A. systole.

77. In the cardiac cycle,

A. the right atrium and the right ventricle contract simultaneously.

B. the two atria relax while the two ventricles contract.

C. the left atrium contracts before the right atrium.

D. all four chambers of the heart contract at the same time.

E. all four chambers of the heart are in systole at the same time.

B. the two atria relax while the two ventricles contract.

78. In the cardiac cycle,

A. the right atrium and the right ventricle contract simultaneously.

B. the left atrium contracts before the right atrium.

C. all four chambers of the heart contract at the same time.

D. all four chambers of the heart are in diastole at the same time.

D. all four chambers of the heart are in diastole at the same time.

79. The period of isovolumetric contraction is immediately followed by

A. the period of ejection.

B. AV node depolarization.

C. passive ventricular filling.

D. atrial contraction.

E. isovolumetric relaxation.

A. the period of ejection.

80. When left atrial pressure exceeds left ventricular pressure,

A. left ventricular ejection begins.

B. aortic blood pressure begins to rise.

C. the bicuspid (mitral) valve opens.

D. ventricular volume decreases.

E. the tricuspid valve opens.

C. the bicuspid (mitral) valve opens.

81. Blood does not enter or leave the ventricles during the period called

A. ejection.

B. rapid filling.

C. atrial systole.

D. isovolumetric contraction.

E. active and passive filling.

D. isovolumetric contraction.

82. During the ejection phase of the cardiac cycle, blood exits the left ventricle through the

A. aorta.

B. coronary sinus.

C. pulmonary vein.

D. superior vena cava.

E. pulmonary trunk.

A. aorta.

83. Pressure in the right ventricle must exceed pressure in the ____ before the right ventricle can eject blood.

A. superior vena cava

B. coronary sinus

C. pulmonary trunk

D. aorta

E. pulmonary veins.

C. pulmonary trunk

84. The chamber of the heart that endures the highest pressure is the

A. right atrium.

B. left atrium.

C. right ventricle.

D. left ventricle.

E. coronary sinus.

D. left ventricle.

85. The tricuspid valve is closed

A. during active filling of the ventricles.

B. when the mitral valve is open.

C. while the atria are contracting.

D. during ejection.

E. during passive filling of the ventricles.

D. during ejection.

86. As soon as left ventricular pressure exceeds the pressure in the aorta, the

A. AV valves open.

B. aortic semilunar valve opens.

C. atria pump blood into the ventricles.

D. ventricles pump blood into the atria.

E. pulmonary semilunar valve closes.

B. aortic semilunar valve opens.

87. During the isovolumetric contraction period of the cardiac cycle,

A. AV and semilunar valves are closed.

B. the atria are contracted.

C. ventricular volume increases.

D. blood is pumped into the large arteries.

E. pressure in the ventricles decreases.

A. AV and semilunar valves are closed.

88. When ventricular pressure exceeds atrial pressure, the

A. ejection occurs.

B. atria pump blood into the ventricles.

C. ventricle is in diastole.

D. blood is pumped into the atrium.

E. AV valves close.

E. AV valves close.

89. What occurs during the time between the first heart sound and the second heart sound?

A. ventricular systole

B. ventricular diastole

C. ventricular filling

D. atrial systole

E. the P wave of the ECG

A. ventricular systole

90. Concerning heart sounds, which of the following is correct?

A. The first heart sound occurs at the beginning of ventricular systole.

B. The second heart sound is heard when the AV valves are closing.

C. The first heart sound is the sound of the semilunar valves closing.

D. The second heart sound occurs when blood flows into the superior vena cava.

E. The first heart sound occurs at the beginning of ventricular diastole.

A. The first heart sound occurs at the beginning of ventricular systole.

91. The first and second heart sounds are most directly related to

A. pulse pressure in the aorta.

B. the contraction of the atria.

C. vibrations that occur when the valves close.

D. contraction of the papillary muscles. E. the flow of the blood.

C. vibrations that occur when the valves close.

92. Which of the following is true?

A. Blood enters the right and left atria only during diastole.

B. Most ventricular filling occurs before the atria contract.

C. During ventricular systole, the AV valves open.

D. The semilunar valves remain closed throughout ventricular systole.

E. Most of end-diastolic volume comes from active filling.

B. Most ventricular filling occurs before the atria contract.

93. Regurgitation of blood flow through the aortic semilunar valve would give rise to

A. the first heart sound.

B. the second heart sound.

C. a heart murmur.

D. an extra heart beat.

E. end-systolic volume.

C. a heart murmur.

94. An incompetent mitral valve may cause blood to back up into the

A. aorta.

B. left atrium.

C. left ventricle.

D. coronary circulation.

E. right atrium.

B. left atrium.

95. The volume of blood pumped during each cardiac cycle is the

A. stroke volume.

B. cardiac output.

C. cardiac reserve.

D. end-systolic volume.

E. end-diastolic volume.

A. stroke volume.

96. The product of the stroke volume times the heart rate is known as the

A. end-diastolic volume.

B. end-systolic volume.

C. cardiac output.

D. cardiac reserve.

E. venous return.

C. cardiac output.

97. End-diastolic volume minus end-systolic volume is equal to

A. cardiac output.

B. cardiac reserve.

C. pulse volume.

D. venous return.

E. stroke volume.

E. stroke volume.

98. Mean arterial pressure is

A. cardiac output times peripheral resistance.

B. end-diastolic volume minus end-systolic volume.

C. maximum cardiac output minus cardiac output when at rest.

D. heart rate times stroke volume.

E. stroke volume times peripheral resistance.

A. cardiac output times peripheral resistance.

99. The dicrotic notch in the aortic pressure curve is due to the

A. increase in intraventricular pressure during ejection.

B. backflow of blood toward the ventricles.

C. closure of the left AV valve.

D. elasticity of the arterial wall.

E. closure of the semilunar valves.

B. backflow of blood toward the ventricles.

100. Afterload is

A. the name given to an increase in end-diastolic volume.

B. the arterial pressure that the ventricles must overcome to eject blood.

C. the amount cardiac output must increase during exercise.

D. another name for venous return.

E. the extent to which ventricular walls are stretched.

B. the arterial pressure that the ventricles must overcome to eject blood.