In a physiology lab, the students designed an experiment to
illustrate how the heart
responds to changes in blood pressure. Everyone relaxed and then
did a headstand. Which of
the following observations are consistent with the change in the
function of their hearts?
A. increased heart rate
B. decreased heart rate
C. increased stroke volume
D. decreased stroke volume
E. both decreased heart rate and increased stroke volume
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.
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.
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.
During hemorrhagic shock in which blood pressure is decreased,
which of the regulatory
mechanisms is most important is increasing cardiac output to
help maintain blood pressure?
A. increased sympathetic stimulation of the heart
B. increase venous return
C. increase in parasympathetic stimulation of the heart
D. increase vagal stimulation of the heart
E. increase in the amplitude of the heart sounds
An incompetent pulmonary semilunar valve could result in less
blood reaching the
B. heart muscle.
C. right ventricle.
E. right atrium.
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
E. right atrium – aorta
Which of the following sequences for the conducting system is
A. AV node, AV bundle, SA node, Purkinje fibers, bundle
B. Purkinje fibers, bundle branches, AV node, AV bundle, SA
C. SA node, AV node, AV bundle, bundle branches, Purkinje
D. SA node, AV bundle, AV node, bundle branches, Purkinje
E. AV node, SA node, bundle branches, AV bundle, Purkinje
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.
Which of the following will depolarize immediately after the AV
A. the AV bundle
B. Purkinje fibers
C. atrial myocardium
D. bundle branches in the ventricular septum
E. the SA node
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.
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.
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.
Which of the following events occurs first?
C. early repolarization
D. final repolarization
E. pacemaker potential
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
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
Which of the following areas of the conduction system would
produce spontaneous action
potentials most frequently if the SA node were not
A. AV bundle
B. Purkinje fibers
C. AV node
D. bundle branch
E. the pacemaker
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.
If cardiac muscle cells are unable to repolarize, this would
A. cardiac output to increase.
B. no harm. These cells can spontaneously depolarize anyway.
C. the heart rate to decrease. It might cause cardiac
D. an increased demand on mitochondria to produce more ATP.
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
E. ectopic focus
What cardiac arrhythmia will have no QRS complex as a
A. atrial fibrillation
B. ventricular fibrillation
D. premature ventricular contractions
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.
Excess potassium ions in cardiac tissue cause
A. an increased heart rate.
B. a rapid repolarization of cardiac cells.
C. a decrease in the frequency of action potentials in the
D. an increase in stroke volume.
E. an increase in the frequency of action potentials.
As soon as left ventricular pressure exceeds the pressure in 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.
Within normal limits, an increase in preload leads to
A. an increase in cardiac output and force of left ventricular
B. a decrease in cardiac output and force of left ventricular
C. an increase in cardiac output and a decrease in force of left
D. a decrease in cardiac output and an increase in the force of
left ventricular contraction.
E. a decrease in stroke volume and heart rate.