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Active Lecture Questions
CHAPTER
18
The
Cardiovascular
System:
The Heart
Copyright © 2010 Pearson Education, Inc.
The principle of complementary structure
and function is evident when examining the
coverings of the heart. In what way is this
relationship evident?
a. The pericardium surrounds the heart.
b. The epicardium and visceral layer of the
pericardium are synonymous.
c. The pericardial cavity surrounds the heart.
d. The visceral and parietal membranes of the
pericardium are smooth and slide past each
other, providing a low-friction environment for
heart movement.
Copyright © 2010 Pearson Education, Inc.
Of the following layers of the heart wall,
which consumes the most energy?
a. Epicardium
b. Myocardium
c. Endocardium
d. Visceral pericardium
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Which of the following structures is an
exception to the general principle
surrounding blood vessel oxygenation
levels?
a. Pulmonary artery
b. Aorta
c. Pulmonary veins
d. Both a and c
Copyright © 2010 Pearson Education, Inc.
What purpose does the coronary circuit
serve?
a. None; it is a vestigial set of vessels.
b. It delivers 1/20 of the body’s blood supply
to the heart muscle itself.
c. It delivers blood to the anterior lung
surface for gas exchange.
d. It feeds the anterior thoracic wall.
Copyright © 2010 Pearson Education, Inc.
A heart murmur would be detected when
blood is heard flowing from the ________ to
the __________ through the ___________.
a. right atrium; right ventricle; tricuspid valve
b. right atrium; left atrium; tricuspid valve
c. left ventricle; left atrium; mitral valve
d. left atrium; left ventricle; mitral valve
Copyright © 2010 Pearson Education, Inc.
The presence of intercalated discs between
adjacent cardiac muscle cells causes the
heart to behave as a _____________.
a. single chamber
b. contractile myofibril
c. desmosome
d. functional syncytium
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Cardiac muscle cells have several
similarities with skeletal muscle cells.
Which of the following is not a similarity?
a. The cells are each innervated by a nerve
ending.
b. The cells store calcium ions in the
sarcoplasmic reticulum.
c. The cells contain sarcomeres.
d. The cells become depolarized when
sodium ions enter the cytoplasm.
Copyright © 2010 Pearson Education, Inc.
The plateau portion of the action potential
in contractile cardiac muscle cells is due to:
a. an increased potassium permeability.
b. an influx of calcium ions.
c. an influx of sodium ions.
d. exit of calcium ions from the sarcoplasmic
reticulum.
Copyright © 2010 Pearson Education, Inc.
The stimulus for the heart’s rhythmic
contractions comes from _________.
a. intercalated discs
b. acetylcholine
c. a neuromuscular junction
d. a pacemaker potential
Copyright © 2010 Pearson Education, Inc.
The major ionic change that initiates the
rising phase of the autorhythmic cell action
potential is __________.
a. potassium ion exit
b. sodium ion entry
c. calcium ion entry
d. calcium ion exit
Copyright © 2010 Pearson Education, Inc.
For which type of heart condition might a
doctor prescribe calcium channel blockers?
a. Depressed heart rate
b. Heart irritability
c. Heart murmur
d. Weak heart rate
Copyright © 2010 Pearson Education, Inc.
In a normal heart, which of the following
structures is responsible for setting the
heart’s pace?
a. Sinoatrial node
b. Atrioventricular node
c. Atrioventricular bundle
d. Purkinje fibers
Copyright © 2010 Pearson Education, Inc.
Predict the nature of an ECG recording
when the atrioventricular node becomes the
pacemaker.
a. There would continue to be a normal sinus
rhythm.
b. The P wave would be much larger than
normal.
c. The rhythm would be slower.
d. The T wave would be much smaller than
normal.
Copyright © 2010 Pearson Education, Inc.
The primary input to the heart by the
cardioinhibitory center is primarily found in
the ___________.
a. sinoatrial node and atrioventricular node
b. Purkinje fibers
c. the cardiac contractile fibers
d. bundle of His
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The “lub-dup” heart sounds are produced
by:
a. the walls of the atria and ventricles
slapping together during a contraction.
b. the blood hitting the walls of the ventricles
and arteries, respectively.
c. the closing of the atrioventricular valves
(“lub”) and the closing of the semilunar
valves (“dup”).
d. the closing of the semilunar valves (“lub”)
and the closing of the atrioventricular
valves (“dup”).
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Atrial systole occurs _______ the firing of
the sinoatrial node.
a. before
b. after
c. simultaneously with
d. alternately with
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The majority (80%) of ventricular filling
occurs ___________.
a. during late ventricular systole
b. passively through blood flow alone
c. with atrial systole
d. both a and b
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In terms of blood flow, why is it important
that atrial diastole occurs just as ventricular
systole begins?
a. Blood is continually propelled in a forward
motion down its pressure gradient.
b. The atria need that time to prepare for the
next contraction.
c. Ventricular systole pulls the remaining
20% of blood volume from the atria.
d. Blood would flow too fast otherwise.
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Cardiac output is determined by________.
a. heart rate
b. stroke volume
c. cardiac reserve
d. both a and b
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Predict what would happen to the end
systolic volume (ESV) if contraction force
were to increase.
a. It would decrease.
b. It would increase.
c. It would remain constant.
d. ESV is not affected by contraction force.
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The Frank-Starling law of the heart can be
demonstrated when an individual takes a
deep breath. This is because:
a. the heart expands during inhalation.
b. the negative intrathoracic pressure
induces a larger than normal venous
return to the right atrium, thereby
stretching the wall of the right ventricle.
c. sympathetic impulses are sent to the heart
during inspiration.
d. both a and c occur.
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Your heart seems to “pound” after you hear
a sudden, loud noise. This increased
contractility is:
a. because you were startled.
b. because when a gasp of surprise is
emitted, the Frank-Starling law of the heart
is evident.
c. due to norepinephrine causing threshold
to be reached more quickly.
d. because acetylcholine release is inhibited.
Copyright © 2010 Pearson Education, Inc.
Predict what happens to end diastolic
volume when an increase in heart rate is not
accompanied by an increase in contractility.
a. End diastolic volume is increased.
b. End diastolic volume is decreased.
c. End diastolic volume is unchanged.
d. End diastolic volume is not affected by
heart rate.
Copyright © 2010 Pearson Education, Inc.
What is the nature of acetylcholine’s
inhibitory effect on heart rate?
a. Acetylcholine induces depolarization in the
sinoatrial node.
b. Acetylcholine causes closing of sodium
channels in the sinoatrial node.
c. Acetylcholine causes opening of fast
calcium channels in contractile cells.
d. Acetylcholine causes opening of
potassium channels in the sinoatrial node,
thereby hyperpolarizing it.
Copyright © 2010 Pearson Education, Inc.
Why is high blood pressure damaging to
the heart?
a. With high blood pressure, the blood is
more viscous and harder to pump.
b. The heart rate slows down to dangerously
low levels if blood pressure is too high.
c. Due to increased afterload, the left
ventricle must contract more forcefully to
expel the same amount of blood.
d. Sodium concentration increases during
high blood pressure and is toxic to the
myocardium.
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