Question 1

The ion primarily responsible for depolarization in pacemaker cells is ________, whereas the ion primarily responsible for this in other cardiac cells is ________.

Accepted Answer

A)   Na+; Ca2+
B)   Ca2+; Na+
C)   K+; Na+
D)   Ca2+; K+E) C) and D)
F) B) and C)

Question 2

Which of the following is a feature shared by cardiac muscle and skeletal muscle?

Accepted Answer

A)   Muscle fiber striations
B)   Dependence upon nervous stimulation
C)   Communication via electrical (gap)  junctions
D)   Intercalated discs
E)   AutorhythmicityF) None of the above
G) B) and D)

Question 3

Calcium channel blockers are frequently used to

Accepted Answer

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 K+ channels.
E)   treat bradycardia and low blood pressure.F) A) and E)
G) B) and E)

Question 4

The long refractory period observed in cardiac muscle

Accepted Answer

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.F) All of the above
G) C) and E)

Question 5

Which statement accurately describes a condition of the heart chambers during the cardiac cycle?

Accepted Answer

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.E) All of the above
F) None of the above

Question 6

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

Accepted Answer

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.E) A) and D)
F) B) and D)

Question 7

The tricuspid valve is closed

Accepted Answer

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.F) A) and B)
G) B) and E)

Question 8

The "pacemaker" of the heart is the

Accepted Answer

A)   right bundle branch.
B)   left bundle branch.
C)   AV node.
D)   SA node.
E)   PM node.F) A) and E)
G) A) and B)

Question 9

Which of the following events occurs first?

Accepted Answer

A)   Threshold
B)   Depolarization
C)   Early repolarization
D)   Final repolarization
E)   Pacemaker potentialF) A) and C)
G) None of the above

Question 10

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

Accepted Answer

A)   Organized in parallel columns or bundles
B)   Contain actin but no myosin
C)   Develop a significant oxygen deficit during systole
D)   Multinucleated like skeletal muscle fibers
E)   Possess special cell-to-cell contacts called intercalated discsF) None of the above
G) A) and D)

Question 11

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

Accepted Answer

A)   right atrium.
B)   left atrium.
C)   right ventricle.
D)   left ventricle.
E)   coronary sinus.F) C) and E)
G) None of the above

Question 12

Why is body temperature sometimes reduced during heart surgery?

Accepted Answer

A)   To slow respiration
B)   To increase heart rate
C)   To decrease heart rate
D)   To increase the oxygen content of bloodE) C) and D)
F) B) and D)

Question 13

Calcium-induced calcium release occurs when

Accepted Answer

A)   Ca2+ from the sarcoplasmic reticulum stimulates the movement of Ca2+ into the cell through the plasma membrane.
B)   Ca2+ is released from both the sarcoplasmic reticulum and the cardiac muscle cell.
C)   the eflux of Ca2+ from the cell results in depolarization.
D)   Ca2+ entering through the plasma membrane stimulates release of Ca2+ from the sarcoplasmic reticulum.E) A) and C)
F) A) and B)

Question 14

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

Accepted Answer

A)   attack
B)   angina
C)   necrosis
D)   cirrhosis
E)   infarctionF) B) and E)
G) A) and D)

Question 15

Under resting conditions, the normal stroke volume is approximately ________.

Accepted Answer

A)   55 mL
B)   70 mL
C)   110 mL
D)   125 mL
E)   180 mLF) All of the above
G) None of the above

Question 16

Identify the structures that contribute to the slow onset of contraction and prolonged contraction phase in cardiac muscle tissue.

Accepted Answer

A)   Desmosomes
B)   Gap junctions
C)   Intercalated discs
D)   T-tubules
E)   Terminal cisternaeF) B) and D)
G) C) and D)

Question 17

The spontaneous opening of Na+ channels marks the beginning of ________ of a cardiac muscle cell.

Accepted Answer

A)   depolarization
B)   repolarization
C)   hyperpolarization
D)   isopolarization
E)   afterpolarizationF) All of the above
G) A) and C)

Question 18

The pericardial sac is lined with

Accepted Answer

A)   fibrous pericardium.
B)   parietal pericardium.
C)   visceral pericardium.
D)   myocardium.
E)   epicardium.F) A) and B)
G) B) and D)

Question 19

After entering the right atrium, the furthest a red blood cell can travel is the ________.

Accepted Answer

A)   right ventricle
B)   pulmonary trunk
C)   superior vena cava
D)   ascending aorta
E)   left atriumF) All of the above
G) B) and C)

Question 20

Ventricular contraction begins at the

Accepted Answer

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.F) A) and E)
G) D) and E)

Exam 20: Cardiovascular System: the Heart

The ion primarily responsible for depolarization in pacemaker cells is ________, whereas the ion primarily responsible for this in other cardiac cells is ________.

Correct AnswerverifiedShow Answer

Which of the following is a feature shared by cardiac muscle and skeletal muscle?

Correct AnswerverifiedShow Answer

Why is body temperature sometimes reduced during heart surgery?

Correct AnswerverifiedShow Answer

Under resting conditions, the normal stroke volume is approximately ________.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Identify the structures that contribute to the slow onset of contraction and prolonged contraction phase in cardiac muscle tissue.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Calcium-induced calcium release occurs when

Correct AnswerverifiedShow Answer

Which statement accurately describes a condition of the heart chambers during the cardiac cycle?

Correct AnswerverifiedShow Answer

The spontaneous opening of Na+ channels marks the beginning of ________ of a cardiac muscle cell.

Correct AnswerverifiedShow Answer

The tricuspid valve is closed

Correct AnswerverifiedShow Answer

The "pacemaker" of the heart is the

Correct AnswerverifiedShow Answer

The pericardial sac is lined with

Correct AnswerverifiedShow Answer

The long refractory period observed in cardiac muscle

Correct AnswerverifiedShow Answer

Calcium channel blockers are frequently used to

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of the following events occurs first?

Correct AnswerverifiedShow Answer

Ventricular contraction begins at the

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

After entering the right atrium, the furthest a red blood cell can travel is the ________.

Correct AnswerverifiedShow Answer

The ion primarily responsible for depolarization in pacemaker cells is , whereas the ion primarily responsible for this in other cardiac cells is .

Correct Answer
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The spontaneous opening of Na⁺ channels marks the beginning of ________ of a cardiac muscle cell.

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