Florida International University

BIO PCB 4023

Chapter 13

1)Keeping blood on the left side of the heart from mixing with the blood on the right side is a function of what structure(s)?

1. 1. valves
   2. septum
   3. arteries
   4. apex
   5. chordae tendineae
2. The primary site of exchange between blood and interstitial fluid occurs across what type of blood vessel?
   1. capillaries B) venules C) veins D) arterioles E) arteries
3. When blood moves through the body it travels in a circular pattern. The general pattern of blood flow follows which sequence of vessels as it leaves the heart?
   1. veins, venules, capillaries, arterioles, arteries
   2. veins, capillaries, venules, arterioles, arteries
   3. arteries, arterioles, capillaries, venules, veins
   4. arterioles, arteries, capillaries, venules, veins
   5. arteries, veins, venules, arterioles, capillaries
4. Although blood is a fluid, nearly half its volume is composed of cells. The most numerous cells are    . The remainder of the cells are     , which help the body defend itself against foreign particles and microorganisms.
   1. erythrocytes : leukocytes B) leukocytes : erythrocytes

C) platelets : leukocytes D) erythrocytes : platelets

5. The circulatory system consists of two divisions and is supplied with blood by different sides of the heart. The right heart supplies blood to the                                                                            circuit, whereas the left heart supplies blood to the                                                                            circuit.
   1. arterial : venule
   2. pulmonary : systemic
   3. systemic : pulmonary
   4. superior (upper body) : inferior (lower body)
   5. oxygenated : deoxygenated
6. Which statement best describes parallel flow in the circulatory system?
   1. In the systemic circuit blood flows from one organ directly to the next, hence in parallel.
   2. Parallel flow refers to the flow of blood just to the heart itself, which keeps it oxygenated at all times.
   3. Parallel flow refers to deoxygenated blood only and not to oxygenated blood.
   4. Parallel flow refers to the flow of electrical impulses in the heart.
   5. The organs of the body are arranged in a parallel circuit to allow adequate flow and pressure to all body systems and maintain homeostasis of blood pressure.

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7. Blood supply to the heart comes from
   1. aorta.
   2. cerebral arteries.
   3. blood within the atria.
   4. coronary arteries.
   5. blood within the ventricles.
8. Which of the following statements best describes a portal system?
   1. Blood flows in one direction throughout the circulatory system.
   2. The portal system allows enough pressure to be generated to close the foramen ovale in the fetal heart.
   3. The portal system is the same as parallel flow.

8. 4. Blood flows from one capillary bed to another, bypassing general circulation.
   5. The portal system refers to ports located in the veins (which does not allow for the backflow of blood).
9. What structure separates the thoracic cavity from the abdominal cavity?
   1. diaphragm B) intestines C) lungs D) heart E) liver
10. Which chamber of the heart has the thickest musculature?
    1. right atrium
    2. left ventricle
    3. left atrium
    4. right ventricle
    5. Both ventricles have equal thickness and are thicker than the atria.
11. The opening and closure of the atrioventricular and semilunar valves is driven by
    1. differences in pressure across the valve.
    2. contraction of the ventricle and atria that pull the valves into place.
    3. contraction of the valve.
    4. contraction and relaxation of the valve.
    5. contraction of muscles attached to the valves.
12. Closure of the atrioventricular valve occurs when
    1. the atrium contracts.
    2. the papillary muscle contracts.
    3. the valve contracts.
    4. pressure inside the ventricle is greater than pressure inside the atrium.
    5. pressure inside the ventricle is less than pressure inside the atrium.

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13. Which of the following statements best describes the function of the chordae tendineae?
    1. They pull downward on the valve cusps, thereby preventing the AV valves from being pushed into the atria (prolapsing).
    2. The chordae tendineae act like a parachute and capture blood as it enters the right ventricle.
    3. They open and close the AV valve due to the movement of the papillary muscle during contraction.
    4. When the heart contracts, the chordate tendineae separate the flow of blood from the right and left sides of the heart.
    5. The chordae tendineae generate autorhythmicity within the heart.
14. What is the primary function of the AV and semilunar valves?
    1. The opening and closing of the valves creates the normal patterns of an EKG.
    2. to permit blood to flow forward while preventing it from flowing backward
    3. to control the speed at which blood enter and leaves the heart
    4. to keep the right and left sides of the heart separated
    5. to coordinate the autorhythmic movements of the heart
15. Whereas the contractile activity of skeletal muscle is called                                              , that of cardiac muscle is                                                                             

because the contraction originates within the musculature itself.

15. 1. neurogenic : myogenic
    2. somatic : autorhythmic
    3. extrinsic : intrinsic
    4. somatic : autonomic
    5. voluntary : involuntary
16. What two major regions of the heart contain a concentration of pacemaker cells?
    1. sinoatrial node and atrioventricular node
    2. sinoatrial node and Purkinje fibers
    3. bundle of His and atrioventricular node

16. 4. bundle of His and Purkinje fibers
    5. sinoatrial node and bundle of His
17. The term autorhythmicity refers to the heart's ability to
    1. conduct action potentials along the conduction pathway.
    2. generate its own contractile cycle.
    3. intrinsically modify its contractility.
    4. act as a functional syncytium.
    5. originate its contraction neurogenically.

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18. What structure provides the pathway for the movement of electrical current between the cells of the conduction pathway and the ventricular muscle fibers?
    1. gap junctions
    2. sodium channels
    3. funny channels
    4. potassium channels
    5. desmosomes
19. Which of the following is the correct conduction pathway through the heart?
    1. SA node, AV node, bundle of His, bundle branches, Purkinje fibers
    2. Bundle of His, bundle branches, Purkinje fibers, SA node, AV node
    3. SA node, Purkinje fibers, AV node, bundle of His, bundle branches
    4. Purkinje fibers, bundle of His, bundle branches, SA node, AV node
    5. AV node, SA node, bundle branches, bundle of His, Purkinje fibers
20. Conduction through which of the following is slow to allow atria to contract before the ventricles?
    1. atria
    2. AV node
    3. Purkinje fibers
    4. SA node
    5. AV bundle (bundle of His)
21. Why do AV nodal cells NOT determine the heart rate under normal circumstances?
    1. As depolarization initiated in the SA node reaches the AV node, it leaves the AV node in a refractory state.
    2. They depolarize slower than all other conducting fibers.
    3. They slow conduction of the wave of excitation.
    4. They depolarize faster than all other conducting fibers.
    5. The AV node is connected to the SA node, but not to other conducting fibers in the heart.
22. Normal resting heart rate is around 70 beats per minute due to the SA node. If the SA node fails, what would you expect the heart beats per minute to be?
    1. 10-20 beats per minute
    2. 30-40 beats per minute
    3. 50 beats per minute
    4. If the SA node fails the individual will go into heart failure and therefore there will be no heart rate.
    5. 70 beats per minute as the AV node takes over for the SA node

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23. If both the SA node and the AV node fail, what would be the expected outcome of impulse rate within the heart?
    1. The sympathetic nervous system takes over and maintains normal heart rate.
    2. The rate would be 30-40 beats per minute due to the concentration of pacemaker cells in the Purkinje fibers.
    3. The heart is autorhythmic therefore it continually beats even after death because death is defined as a

lack of brain waves.

23. 4. The individual would be in heart failure or have a myocardial infarction due to the lack of a beating heart.
    5. The vagus nerve takes over and maintains a normal heart rate.
24. The rapid depolarization phase of a pacemaker cell action potential is caused by movement of
    1. potassium through funny channels.
    2. calcium through T-type channels.
    3. sodium through funny channels.
    4. sodium and calcium through funny channels.
    5. calcium through L-type channels.
25. Which of the following is responsible for the rapid depolarization phase of an action potential within the pacemaker cells?
    1. a decrease in PK
    2. an increase in PK
    3. an increase in PNa
    4. an increase in PCa
    5. a decrease in PNa
26. Which of the following is responsible for the repolarization of pacemaker cells?
    1. an increase in PNa
    2. an increase in PCa
    3. an increase in PK
    4. a decrease in PK
    5. a decrease in PNa
27. What causes the rapid depolarization phase of a contractile cell action potential?
    1. calcium movement into the cell
    2. potassium movement into the cell
    3. sodium movement into the cell
    4. sodium movement out of the cell
    5. calcium movement out of the cell

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28. During repolarization (phase 3) of a contractile cell action potential,
    1. only sodium permeability is increased.
    2. only calcium permeability is increased.
    3. only potassium permeability is increased.
    4. sodium and calcium permeability are both increased.
    5. sodium and potassium permeability are both increased.
29. Which of the following ion channels does NOT participate in the contractile cell action potential?
    1. inward rectifying potassium channels
    2. voltage-gated sodium channels
    3. type T calcium channels
    4. delayed rectifying potassium channels
    5. type L calcium channels
30. Which of the following is NOT a part of the excitation-contraction coupling in cardiac muscle?
    1. An action potential travels along transverse tubules.
    2. Calcium opens calcium channels in the sarcoplasmic reticulum.
    3. Calcium channels in the plasma membrane open, allowing calcium ions to enter the cell.
    4. Calcium channels in the sarcoplasmic reticulum open, allowing calcium ions to enter the cytosol.
    5. Calcium binds to calmodulin in the cytosol.

31. What is the function of the sodium-calcium exchanger in cardiac muscle?
    1. trigger the release of calcium from the sarcoplasmic reticulum
    2. depolarize the cell
    3. remove calcium from the cytosol by transporting it into the sarcoplasmic reticulum
    4. remove calcium from the cytosol by transporting it to the extracellular fluid thereby relaxing the muscle
    5. interact with troponin to initiate cross-bridge cycling
32. Which of the following components of an ECG represents atrial depolarization?
    1. P wave
    2. QRS complex
    3. T wave
    4. PQ interval
    5. TQ segment
33. Which of the following components of an ECG represents ventricular depolarization?
    1. P wave
    2. QRS complex
    3. T wave
    4. PQ interval
    5. TQ segment

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34. Which of the following components of an ECG represents ventricular repolarization?
    1. P wave
    2. QRS complex
    3. T wave
    4. PQ interval
    5. TQ segment
35. Which statement best describes why atrial depolarization is usually not detected on a normal ECG?
    1. The voltage change in the atria is minimal and therefore does not register on an ECG.
    2. It occurs at the same time as the QRS complex.
    3. The electrodes cannot be placed high enough on the chest to detect the atria.
    4. The atria are so small and the depolarization happens so quickly that it cannot be detected.
    5. The atria do not contract only the AV valves open.
36. The Q-T interval is the time from the onset of the QRS complex to the end of the T wave which measures
    1. the amount of time between each heartbeat.
    2. the time of atrial systole.
    3. the time of ventricular systole.
    4. the time of ventricular diastole.
    5. the time of atrial diastole.
37. The T-Q segment is the time from the end of the T wave to the beginning of the QRS complex which measures the time
    1. between heartbeats.
    2. of atrial diastole.
    3. of ventricular diastole.
    4. of ventricular systole.
    5. of atrial systole.
38. The R-R interval is the time between the peaks of two successive QRS complexes and represents
    1. ventricular diastole.
    2. atrial systole.
    3. atrial diastole.

38. 4. ventricular systole.
    5. the amount of time between heartbeats.
39. If damage to the AV node slowed down conduction through this tissue, what would be observed on an ECG?
    1. a longer P wave
    2. a larger P wave
    3. a wider QRS complex
    4. a longer PR interval
    5. an inverted T wave

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40. In an ECG recording, the RR interval is 0.5 seconds. What is the heart rate?
    1. 120 beats/min
    2. 50 beats/min
    3. 100 beats/min
    4. 60 beats/min
    5. 30 beats/min
41. Which of the following describes second-degree heart block?
    1. There is a longer delay between atrial contraction and ventricular contraction.
    2. Not every atrial contraction is followed by a ventricular contraction.
    3. The ventricles no longer contract.
    4. Not every ventricular contraction is preceded by an atrial contraction.
    5. The atria no longer contract.
42. Which statement best describes why clinicians use a defibrillator?
    1. The ventricles of the heart are so large that only a strong current can make them depolarize, which is needed in order for them to contract and get blood to the body.
    2. The applied current opens up voltage gated calcium channels in the atria causing the heart to begin a new P wave.
    3. The applied current repolarizes the cells of the heart, hence resetting the heart for normal rhythm.
    4. The applied current depolarizes all the muscle cells at the same time, returning synchronous electrical activity to the heart.
    5. A defibrillator takes the place of the SA node and must be applied every minute to keep the heart rate normal until it regains its strength and beats on its own.

43. During isovolumetric relaxation,
    1. the AV and semilunar valves are closed and ventricular pressure is increasing.
    2. the AV and semilunar valves are open and ventricular pressure is increasing.
    3. the AV and semilunar valves are open and ventricular pressure is decreasing.
    4. the AV and semilunar valves are closed and ventricular pressure is decreasing.
    5. the AV valves are open, the semilunar valves are closed, and ventricular pressure is decreasing.
44. What is occurring during ventricular ejection?
    1. The AV valves are open and the semilunar valves are closed as ventricular pressure is. increasing
    2. The AV and semilunar valves are closed as ventricular pressure is increasing.
    3. The AV and semilunar valves are open as blood is leaving the ventricles.
    4. The AV valves are closed and the semilunar valves are open as blood is leaving the ventricles.
    5. The AV valves are open and the semilunar valves are closed as blood is leaving the ventricles.

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45. Which of the following is TRUE of the ventricular filling phase of the cardiac cycle?
    1. Ventricular pressure is less than aortic pressure.
    2. Ventricular pressure is greater than atrial pressure.
    3. Ventricular filling occurs during systole.

45. 4. Ventricular pressure is decreasing.
    5. All valves in the heart are open.
46. What phase of the cardiac cycle is the heart in when all four valves of the heart are closed and ventricular pressure is building, but is not yet great enough to open a valve?
    1. ventricular filling
    2. isovolumetric relaxation
    3. isovolumetric contraction
    4. ventricular ejection
    5. none
47. During which phase of the cardiac cycle are all four heart valves open?
    1. isovolumetric contraction
    2. ventricular filling
    3. ventricular ejection
    4. isovolumetric relaxation
    5. none
48. Ejection of blood from the right ventricle will continue until
    1. pressure in the pulmonary artery is greater than pressure in the right ventricle.
    2. pressure in the aorta is less than pressure in the right ventricle.
    3. the pulmonary semilunar valve contracts, inducing closure.
    4. pressure in the aorta is greater than pressure in the right ventricle.
    5. pressure in the pulmonary artery is less than pressure in the right ventricle.
49. The increase in ventricular volume early in diastole reflects the
    1. increased stiffness of the heart.
    2. passive movement of blood through the atrium and into the ventricle.
    3. relaxation of the ventricle.
    4. back-flow of blood from the aorta.
    5. contraction of the atria moving blood into the ventricle.
50. The small increase in ventricular pressure observed late in diastole is caused by
    1. ventricular relaxation.
    2. atrial contraction.
    3. atrial relaxation.
    4. ventricular contraction.
    5. blood moving into the atria from vena cava.

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51. Blood is ejected from the left ventricle once pressure within the
    1. ventricle is greater than pressure within the aorta.
    2. ventricle is less than pressure within the aorta.
    3. ventricle is greater than pressure within the pulmonary artery.
    4. ventricle is less than pressure within the pulmonary artery.
    5. muscles of the pulmonary semilunar valve relax.
52. The increased aortic pressure that occurs during systole reflects a(n)
    1. increased volume of blood in the aorta.
    2. decreased resistance of the vasculature.
    3. decreased stiffness of the aorta.
    4. increased resistance of the vasculature.
    5. decreased volume of blood within the aorta.
53. The end-diastolic volume minus the end-systolic volume is the
    1. total ventricular volume.

1. 2. total atrial volume.
   3. stroke volume.
   4. cardiac output.
   5. ejection fraction.

54. The volume of blood ejected from the ventricle with each contraction can be described by the equation
    1. (end-systolic volume) - (stroke volume).
    2. (stroke volume) - (end-diastolic volume).
    3. (end-diastolic volume) - (end-systolic volume).
    4. (ejection fraction) × (end-diastolic volume).
    5. (pulse pressure) - (end-diastolic volume).
55. Given end-diastolic volume = 130 mL and end-systolic volume = 50 mL, what is the stroke volume and ejection fraction?

A) SV = 50 mL, EF = 0.61

B) SV = 180 mL, EF = 0.61

C) SV = 80 mL, EF = 0.38

D) SV = 80 mL, EF = 0.61

E) SV = 180 mL, EF = 0.38

56. What causes the sounds that one hears as the heart beats?
    1. the turbulence created as the valves close
    2. the turbulence created as the valves open
    3. the snapping of the valves into the open position
    4. the bulk movement of blood into and out of the ventricle
    5. the snapping of the valves into a closed position

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57. Cardiac output is determined by what two variables?
    1. heart rate and stroke volume
    2. stroke volume and ejection fraction
    3. end-diastolic volume and end-systolic volume
    4. preload and afterload
    5. heart rate and ejection fraction
58. Regulation of the heart (or any organ or tissue) by neural input, circulating hormones, or any other factor originating from outside the organ is referred to as   control.
    1. voluntary B) extrinsic C) myogenic D) neurogenic E) intrinsic
59. Which of the following structures is poorly innervated by the parasympathetic nervous system and, therefore, an increase in parasympathetic activity has little effect on this structure?
    1. atrioventricular node
    2. ventricles
    3. conduction pathway
    4. Purkinje fibers
    5. sinoatrial node
60. The SA node is innervated by the
    1. somatic nervous system only.
    2. parasympathetic nervous system only.
    3. sympathetic nervous system only.
    4. sympathetic and parasympathetic nervous systems.
    5. sympathetic, parasympathetic, and somatic nervous systems.
61. Which of the following is an effect of parasympathetic activity to the heart?
    1. SA nodal cells are depolarized.

1. 2. Postganglionic neurons release acetylcholine, which binds to nicotinic cholinergic receptors in the SA node.
   3. Heart rate is increased.
   4. The rate of spontaneous depolarization in SA nodal cells decreases.
   5. cAMP is activated.

62. Which of the following is a FALSE statement about sympathetic activity to the SA node?
    1. The rate of spontaneous depolarization is increased.
    2. cAMP levels in the pacemaker cells increases.
    3. Norepinephrine binds to beta1 adrenergic receptors.
    4. Potassium channel closing is enhanced.
    5. Funny channel opening is enhanced.

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63. Under resting conditions, heart rate is primarily under the control of what control system?
    1. epinephrine
    2. the parasympathetic nervous system
    3. intrinsic mechanisms
    4. the sympathetic nervous system
    5. the somatic nervous system
64. An increase in heart rate can be mediated through which of the following?
    1. a decrease in parasympathetic nervous activity only
    2. a decrease in sympathetic activity only
    3. an increase in sympathetic activity only
    4. an increase in parasympathetic activity and a decrease in sympathetic activity
    5. a decrease in parasympathetic activity and an increase in sympathetic activity
65. Which of the following would NOT result from an increase in ventricular contractility?
    1. increased stroke volume
    2. decreased end-systolic volume
    3. increased ejection fraction
    4. decreased end-diastolic volume
    5. increased proportion of end-diastolic volume that is ejected
66. Which of the following best describes the effect of sympathetic activity on ventricular contractile cells?
    1. The rates of contraction and relaxation both decrease, whereas the force of contraction increases.
    2. The rates of contraction and relaxation both increase, whereas the force of contraction decreases.
    3. The rate of contraction and the force of contraction both increase, whereas the rate of relaxation decreases.
    4. The force of contraction increases, whereas the rates of contraction and relaxation are not affected.
    5. The rates of contraction and relaxation and the force of contraction all increase.
67. Which of the following describes the effect of end-diastolic volume on stroke volume?
    1. A decrease in end-diastolic volume creates a vacuum drawing more blood into the ventricle increasing stroke volume.
    2. An increase in end-diastolic volume stretches ventricular muscle cells to lengths greater than optimum, decreasing the strength of contraction and thereby decreasing stroke volume.
    3. A decrease in end-diastolic volume allows ventricular muscle cells to relax more during diastole, allowing more blood to return to the heart increasing stroke volume.
    4. An increase in end-diastolic volume stretches ventricular muscle cells to lengths closer to optimum, increasing the strength of contraction and thereby increasing stroke volume.
    5. A decrease in end-diastolic volume allows cardiac muscle to relax, conserving energy for the next contraction, thereby increasing stroke volume of that next contraction.

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68. Which of the following variables is NOT an intrinsic factor that alters cardiac function?
    1. end-systolic volume
    2. hormonal stimulation
    3. Starling's law
    4. preload
    5. atrial pressure
69. Starling curves plot          against            .
    1. stroke volume : end-systolic volume
    2. heart rate : end-systolic volume
    3. heart rate : end-diastolic volume
    4. cardiac output : end-diastolic volume
    5. stroke volume : end-diastolic volume
70. The preload is approximately the same as the pressure.
    1. aortic diastolic
    2. aortic systolic
    3. end-systolic
    4. end-diastolic
    5. atrial
71. Which of the following factors determines preload?
    1. heart rate and venous return
    2. parasympathetic activity of the ventricles
    3. end-diastolic volume and end-systolic volume
    4. peripheral resistance and tension
    5. the pressure in the aorta and the lungs
72. An increase in venous return would result in a(n)
    1. increase mid-systolic volume.
    2. decreased end-systolic volume.
    3. increased end-diastolic volume.
    4. decreased end-diastolic volume.
    5. increased end-systolic volume.
73. Which of the following variables is NOT involved in determining ventricular preload?
    1. atrial pressure
    2. central venous pressure
    3. venous return
    4. afterload
    5. filling time

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74. A decrease in afterload will lead to which of the following?
    1. decreased cardiac output
    2. decreased heart rate
    3. decreased stroke volume
    4. increased heart rate
    5. increased stroke volume
75. Which of the following decreases heart rate?
    1. increase in sympathetic activity
    2. increase in parasympathetic activity
    3. increase in filling time
    4. increase in stroke volume
    5. increase in venous pressure

76. Which heart structure receives deoxygenated blood from veins?
    1. right atrium
    2. left ventricle
    3. left atrium
    4. right ventricle
    5. AV bundle (bundle of His)
77. Which heart structure receives blood from the pulmonary veins?
    1. right atrium
    2. left ventricle
    3. left atrium
    4. right ventricle
    5. AV bundle (bundle of His)
78. Where is the SA node located?
    1. right atrium
    2. left ventricle
    3. left atrium
    4. right ventricle
    5. AV bundle (bundle of His)
79. The mitral valve separates what chamber from its associated ventricle?
    1. right atrium
    2. left ventricle
    3. left atrium
    4. right ventricle
    5. AV bundle (bundle of His)

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80. What chamber empties into the aorta?
    1. right atrium
    2. left ventricle
    3. left atrium
    4. right ventricle
    5. AV bundle (bundle of His)
81. What chamber has the thickest myocardium?
    1. right atrium
    2. left ventricle
    3. left atrium
    4. right ventricle
    5. AV bundle (bundle of His)
82. During isovolumetric contraction, which chamber has the greatest pressure?
    1. right atrium
    2. left ventricle
    3. left atrium
    4. right ventricle
    5. AV bundle (bundle of His)
83. Which chamber is connected to the pulmonary arteries?
    1. right atrium
    2. left ventricle
    3. left atrium
    4. right ventricle

83. 5. AV bundle (bundle of His)
84. Which channel type allows sodium movement into the cell during the early spontaneous depolarization in autorhythmic cells?
    1. potassium channels
    2. T-type calcium channels
    3. funny channels
    4. L-type calcium channels
    5. voltage-gated sodium channels
85. Which channel type allows calcium movement into the cell during the late spontaneous depolarization in autorhythmic cells?
    1. potassium channels
    2. T-type calcium channels
    3. funny channels
    4. L-type calcium channels
    5. voltage-gated sodium channels

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86. Which channel type allows ion movement out of the cell during repolarization of the autorhythmic cells?
    1. potassium channels
    2. T-type calcium channels
    3. funny channels
    4. L-type calcium channels
    5. voltage-gated sodium channels
87. Which channel type is responsible for ion movement during the depolarization phase of the autorhythmic cell action potential?
    1. potassium channels
    2. T-type calcium channels
    3. funny channels
    4. L-type calcium channels
    5. voltage-gated sodium channels
88. What channels open during the plateau phase of the cardiac contractile cell action potential?
    1. potassium channels
    2. T-type calcium channels
    3. funny channels
    4. L-type calcium channels
    5. voltage-gated sodium channels
89. Opening of what channels is responsible for the depolarization phase of the cardiac contractile cell action potential?
    1. potassium channels
    2. T-type calcium channels
    3. funny channels
    4. L-type calcium channels
    5. voltage-gated sodium channels
90. Which component of an ECG represents ventricular depolarization?
    1. P wave
    2. P-R interval
    3. T wave
    4. Q-T interval
    5. QRS complex

91. Which component of an ECG represents atrial depolarization?
    1. P wave
    2. P-R interval
    3. T wave
    4. Q-T interval
    5. QRS complex

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92. Which component of an ECG represents ventricular repolarization?
    1. P wave
    2. P-R interval
    3. T wave
    4. Q-T interval
    5. QRS complex
93. Which component of an ECG represents ventricular systole?
    1. P wave
    2. P-R interval
    3. T wave
    4. Q-T interval
    5. QRS complex
94. Which component of an ECG represents ventricular diastole?
    1. T-Q segment
    2. QRS complex
    3. T wave
    4. Q-T interval
    5. P-R interval
95. Which component of an ECG represents the AV nodal conduction time?
    1. QRS complex
    2. T wave
    3. Q-T interval
    4. P-R interval
    5. T-Q segment
96. In what phase is the cardiac cycle when all four valves are closed and pressure in the ventricle is decreasing?
    1. atrial contraction
    2. ventricular filling
    3. isovolumetric contraction
    4. isovolumetric relaxation
    5. ventricular ejection
97. In what phase of the cardiac cycle does ventricular pressure exceed aortic pressure?
    1. atrial contraction
    2. ventricular filling
    3. isovolumetric contraction
    4. isovolumetric relaxation
    5. ventricular ejection

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98. In what phase is the cardiac cycle when the AV valves are open and semilunar valves are closed?
    1. atrial contraction
    2. ventricular filling
    3. isovolumetric contraction
    4. isovolumetric relaxation

98. 5. ventricular ejection
99. In what phase is the cardiac cycle when the semilunar valves are open and AV valves are closed?
    1. atrial contraction
    2. ventricular filling
    3. isovolumetric contraction
    4. isovolumetric relaxation
    5. ventricular ejection
100. The second heart sound coincides with the beginning of which period in the cardiac cycle?

1. atrial contraction
2. ventricular filling
3. isovolumetric contraction
4. isovolumetric relaxation
5. ventricular ejection

101. Blood returns to the left atrium via what blood vessels?

1. superior and inferior vena cavae
2. coronary artery
3. iliac vein
4. pulmonary veins
5. aorta

102. What are the three layers of the heart, from inside to outside?

1. myocardium, endothelium, and epicardium
2. myocardium, epicardium, and endothelium
3. endothelium, myocardium, and epicardium
4. endothelium, epicardium, and myocardium
5. epicardium, myocardium, and endothelium

103. Blood is moved through the pulmonary vasculature by pressure generated within the

1. aorta.
2. right atrium.
3. right ventricle.
4. left ventricle.
5. left atrium.

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104. What component of the conduction pathway transmits the action potential to the ventricular contractile cells?

1. AV node
2. Purkinje fibers
3. bundle of His
4. nodal pathways
5. SA node

105. What is the pacemaker of the heart?

1. SA node
2. bundle of His
3. Purkinje fibers
4. AV node
5. nodal pathways

106. The initial depolarization that occurs in pacemaker cells is caused by closing of        channels and opening of            channels.

1. sodium : funny

2. potassium : funny
3. sodium : T-type calcium
4. sodium : L-type calcium
5. potassium : T-type calcium

107. The depolarization of the action potential in the pacemaker cells is driven by the rapid influx of    

ions through           channels.

1. calcium : L-type calcium
2. potassium : funny
3. sodium : T-type calcium
4. potassium : T-type calcium
5. sodium : funny

108. The period of ventricular contraction is called , whereas the period of ventricular relaxation is called

             .

1. action potential : refractory period
2. V fib : A fib
3. diastole : systole
4. systole : diastole
5. action potential : graded potential

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109. The P wave of the electrocardiogram is created by

1. atrial depolarization.
2. ventricular depolarization.
3. ventricular repolarization.
4. atrial hyperpolarization.
5. atrial repolarization.

110. The repolarization of the ventricle is reflected in the   of the electrocardiogram.

1. R-R interval
2. QRS complex
3. T wave
4. P-Q interval
5. P wave

111. The volume of blood that is pumped by the heart every minute is determined by the equation

1. CO = HR × SV.
2. BP - PR × VL.
3. SV = EDV - ESV.
4. T = PR/2.
5. EF = EDV - ESV.

112. What is the equation relating stroke volume (SV), end-diastolic volume (EDV), and end-stroke volume (ESV)?

1. SV = EDV × ESV
2. SV = EDV/ESV
3. SV = EDV + ESV/3
4. SV = EDV - ESV
5. SV = EDV + ESV

113. Describe the structures of the heart that are responsible for regulating the movement of blood from one chamber to the next.

114. Ion channels within the conduction system of the heart determine the frequency of contractile cycles generated by the heart. Describe the autorhythmic properties of the heart, with particular emphasis on the ion channels involved in the pacemaker potentials.
115. The pathway by which action potentials from the sinoatrial node travel through the heart is important for the normal function of the heart. Describe the conduction pathway of the heart and how that path

corresponds to electrical events in an ECG reading.

116. Contraction of the ventricular contractile cells originates from the Purkinje cells. Describe the electrical events responsible for the action potential of the ventricle.
117. Describe the changes in pressure and volume that occur within the left ventricle throughout the course of the cardiac cycle, starting at the beginning of diastole.
118. Cardiac output is in part determined by changes in heart rate. Describe the factors that are responsible for inducing changes in heart rate.