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Chapter 20 The heart

front 1

Which network of blood vessels carries blood to and from the gas exchange surfaces in the lungs?

back 1

Pulmonary Circuit

front 2

Which vessels have very thin walls and are often called exchange vessels because they allow for the exchange of nutrients, gases, and wastes with surrounding tissues?

back 2

Capillaries

front 3

Which layer of the heart wall is the visceral pericardium?

back 3

Epicardium

front 4

Which chamber of the heart receives blood from the superior and inferior venae cavae?

back 4

Right Atrium

front 5

Which chamber contains trabeculae carneae?

back 5

Right and Left Ventricles

front 6

The left ventricle pumps blood into the __________.

back 6

Ascending Aorta

front 7

Which valve is found between the right atrium and the right ventricle?

back 7

Tricuspid Valve

front 8

The right and left coronary arteries originate at the base of the __________.

back 8

Ascending Aorta

front 9

A large vein that opens into the right atrium and brings in venous blood from the heart tissue is the __________.

back 9

Coronary Sinus

front 10

Which of the following is called the cardiac pacemaker?

back 10

The sinoatrial node is called the cardiac pacemaker because it establishes heart rate.

front 11

What structures in the conduction system conduct impulses very rapidly to the ventricular myocardium?

back 11

Purkinje Fibers

front 12

The QRS complex on the ECG represents __________.

back 12

Ventricular Depolarization

front 13

The plateau in the action potential is caused by the entry of ________ ions.

back 13

Calcium

front 14

What is the term for contraction of a heart chamber?

back 14

Systole

front 15

What occurs during the first phase of ventricular systole?

back 15

The AV valves close, and ventricular pressure rises.

front 16

What produces the "lubb" of the first heart sound?

back 16

closing of the atrioventricular valves

front 17

What is measured in milliliters per beat?

back 17

stroke volume

front 18

What effect does epinephrine have on the SA node?

back 18

increases heart rate

front 19

What could increase the strength of the contraction of a ventricle?

back 19

increased stretch on the ventricle

front 20

Which of the following statements about autonomic tone is FALSE?

Resting heart rate will be 70–80 beats per minute.
Parasympathetic rates dominate in a resting healthy adult.
ACh and NE are released at the nodes.
Sympathetic effects dominate in a resting healthy adult.

back 20

Sympathetic effects dominate in a resting healthy adult.

front 21

Label the following structures of the conducting system of the heart.

back 21

A. AV Bundle
B. Purkinje Fibers
C. SA Node
D. Internodal Pathways
E. AV Node

front 22

Label the following activities of the impulse conduction through the heart.

back 22

E. SA node activity and atrial activation begin.
C. Electrical impulses spread across both atria.
A. Atrial contraction begins.
D. The electrical impulse moves down the interventricular septum.
B. Atrial contraction is over and ventricular contraction begins.

front 23

Put the following steps to blood flow through the heart in the correct order:

A. venae cavae
B. right ventricle
C. pulmonary arteries
D. pulmonary veins
E. pulmonary trunk
F. right atrium

back 23

A. venae cavae
F. right atrium
B. right ventricle
E. pulmonary trunk
C. pulmonary arteries
D. pulmonary veins

front 24

Beginning at the natural pacemaker region, arrange the components of the heart's conducting system in the order that an action potential would pass, by matching (1) through (6):

a. AV bundle (bundle of His)
b. internodal pathways
c. Purkinje fibers
d. atrioventricular (AV) node
e. sinoatrial (SA) node
f. left and right bundle branches

back 24

E. SA node
B. Internodal pathways
D. AV node
A. AV bundle
F. left and right bundle branches
C. Purkinje Fibers

front 25

Put the steps of the cardiac cycle in order, beginning with the resting period between heart beats.
a. Ventricular diastole early
b. Ventricular diastole late
c. Atrial systole
d. Ventricular systole first phase
e. Ventricular systole second phase
f. Atrial diastole

back 25

C. Atrial Systole
F. Atrial Diastole
D. Ventricular Systole 1st phase
E. Ventricular Systole 2nd phase
A. Ventricular Diastole Early
B. Ventricular Diastole Late

front 26

P wave

back 26

Depolarization of the atria

front 27

P-R Interval

back 27

Transmission of the impulse to contract from the SA node to the AV node and through the ventricles

front 28

QRS complex

back 28

Ventricular depolarization

front 29

Q-T interval

back 29

Time required for the ventricles to undergo a single cycle of depolarization and repolarization

front 30

T wave

back 30

Repolarization of ventricles

front 31

Vessels that carry blood away from the heart are called __________.

back 31

Arteries

front 32

When the heart beats, the __________ contract first.

back 32

atria

front 33

The left atrium collects blood from the __________ and empties into the left ventricle.

back 33

pulmonary circuit

front 34

When blood is ejected from the heart, it is pushed from the ____ to the _____.
atria; ventricle
apex; base
ventricle; atria
base; apex

back 34

apex; base

front 35

The heart has _____ chambers and ______ valves.

back 35

4;4

front 36

The epicardium of the heart is the same as the __________.

back 36

visceral pericardium

front 37

On the outside of the heart, the boundaries between the right and left ventricles are marked by the __________.

back 37

anterior interventricular sulcus and the posterior interventricular sulcus

front 38

The expandable outer portion of each atrium is called __________.

back 38

an auricle

front 39

The right atrium receives blood from the __________.

superior vena cava
coronary sinus
inferior vena cava
All of the listed responses are correct.

back 39

All of the listed responses are correct.

front 40

The AV valves prevent the backflow of blood into the _____, and the semilunar valves prevent backflow of blood into the _____.

back 40

atria; ventricles

front 41

The right and left AV valves are also called the ______ and _______, respectively.

back 41

tricuspid; bicuspid

front 42

The free edges of the AV valves are attached to fibers called __________.

back 42

chordae tendineae

front 43

The left atrium receives blood from the __________.

back 43

pulmonary veins

front 44

The innermost layer of the heart is called the __________.

back 44

endocardium

front 45

Deoxygenated blood leaves the right ventricle through a semilunar valve and enters the __________.

back 45

pulmonary trunk

front 46

Which of the following statements concerning the heart is FALSE?

The heart sits at an angle to the longitudinal axis of the body.
The heart lies slightly to the left of midline.
The heart is rotated toward the right.
The heart is surrounded by the pericardial cavity.

back 46

The heart is rotated toward the right.

front 47

Compared to the right ventricle, the left ventricle __________.

develops less pressure during contraction
holds less blood
has a thicker wall
increases in diameter during contraction

back 47

has a thicker wall

front 48

The valve known as the mitral valve is located __________.

back 48

between the left atrium and left ventricle

front 49

Marginal branches are extensions of the __________.

back 49

right coronary artery

front 50

In contrast to skeletal muscle, cardiac muscle cells have a _______ phase as part of their action potential.

back 50

Plateau

front 51

The SA node acts as the pacemaker of the heart because these cells are __________.

back 51

the cells that depolarize and reach threshold first

front 52

The refractory period of cardiac muscles is __________ than that of skeletal muscles.

back 52

longer

front 53

If undisturbed, the cells of the AV node will depolarize about __________ times per second.

back 53

40–60

front 54

Without external interactions, the cells of the SA node depolarize __________ times per minute.

back 54

80-100

front 55

The Purkinje fibers __________.
conduct impulses very slowly
do not conduct impulses
conduct impulses rapidly
spontaneously depolarize 100 times per second

back 55

conduct impulses rapidly

front 56

The bundle branches ___________.

extend to the apex of the heart
transmit impulses to the left and right ventricle.
conduct impulses to the Purkinje fibers
All of the listed responses are correct.

back 56

All of the listed responses are correct

front 57

The QRS complex represents __________.

back 57

Ventricular Depolarization

front 58

The P wave represents __________.

back 58

Atrial Depolarization

front 59

The T wave represents _________.

back 59

Ventricular Repolarization

front 60

Which of the following correctly describes conducting cells of the SA node?

They are smaller than contractile cells.
They cannot maintain a stable resting potential.
They generate actions potentials at a rate of 80–100 per minute.
All of the listed responses are correct.

back 60

All of the listed responses are correct.

front 61

The contractile cells of the myocardium reach threshold because of an influx of ____.

back 61

cations

front 62

Which of the following statements concerning contractile cells and the heartbeat is INCORRECT?

The opening of fast channels in the membranes of contractile cells results in a rapid depolarization.
During the absolute refractory period, the membrane is incapable of responding to a new stimulus.
The plateau phase of the contractile cell's action potential is the result of calcium ions moving out of the cell.
Contractile cells form the bulk of the atrial and ventricular walls.

back 62

The plateau phase of the contractile cell's action potential is the result of calcium ions moving out of the cell.
********

front 63

The conduction delay that occurs at the AV node allows __________.

back 63

the atria to contract before the ventricles begin to contract

front 64

An elderly man is brought into the hospital on a hot, sunny day complaining of light-headedness. You administer an ECG and notice that the P–R interval is 350 msec. His heart sounds are normal. His blood tests indicate that the LDH, SGOT, CK, and CK-MB levels are all normal. What is wrong with this patient?

back 64

The man has a problem with the conduction system of the atria or possibly with the AV node.

front 65

During ventricular filling, the AV valves are ____, and the semilunar valves are _______.

back 65

open;closed

front 66

Contraction of the chambers of the heart is called _____, and relaxation of the chambers of the heart is called _____.

back 66

systole;diastole

front 67

When atrial contraction begins, the ventricles are __________.

back 67

relaxed and filling

front 68

The dicrotic notch marks the point when the __________.

back 68

aortic valve closes

front 69

The first heart sound, "lubb," marks the point when __________.

back 69

the atrioventricular valves close

front 70

There is (are) __________ heart sound(s).

back 70

4

front 71

Which of the following statements concerning atrial systole is FALSE?

The volume of blood in the ventricle at the end of atrial systole is end-diastolic volume, or EDV.
During atrial systole, blood moves from the atrium to the ventricle through the AV valve.
During atrial systole, the pressure in the atrium is higher than the pressure in the ventricle.
At the start of atrial systole, there is very little blood in the ventricles.

back 71

At the start of atrial systole, there is very little blood in the ventricles.

front 72

Which of the following statements concerning ventricular diastole is FALSE?

The elasticity of the connective tissues of the heart and fibrous skeleton causes ventricles to expand during ventricular diastole.
At the beginning of ventricular diastole, both the AV valves and semilunar valves are closed.
As the ventricles begin to fill with blood, the pressure in the chamber rises.
When the AV valves initially open, both the atria and the ventricles are in diastole.

back 72

As the ventricles begin to fill with blood, the pressure in the chamber rises.

front 73

The stroke volume of the heart is approximately __________.

back 73

80mL

front 74

Stroke volume is defined as __________.

back 74

the amount of blood ejected from each ventricle during ventricular systole

front 75

Cardiac output is defined as __________.

HR × (EDV − ESV)
HR × EDV
HR × SV
both HR × SV and HR × (EDV − ESV)
None of the listed responses is correct.

back 75

both HR × SV and HR × (EDV − ESV)

front 76

Which statement(s) is (are) true with regard to preload?

If EDV is greater and ESV is lower, then the stroke volume increases.
Preload is increased with a rapid heartbeat.
During exercise, increased venous return increases EDV.
If EDV is greater and ESV is lower, then the stroke volume increases; AND during exercise, increased venous return increases EDV.
All of these statements are true.

back 76

If EDV is greater and ESV is lower, then the stroke volume increases; AND during exercise, increased venous return increases EDV.

front 77

Starling's law of the heart refers to the relationship between __________.

back 77

EDV and SV

front 78

Which of the following would be considered a positive inotropic agent?

beta-blocking medications
acetylcholine
calcium-blocking medications
digitalis

back 78

digitalis

front 79

In a normal resting adult, the effects of the __________ division of the autonomic nervous system dominate.

back 79

parasympathetic

front 80

The cardiac output (CO) is equal to __________.

back 80

SV x HR

front 81

Which of the following is NOT a factor that controls stroke volume?

sympathetic stimulation of the myocardium
cardiac output
contractility of the heart
end-systolic volume
end-diastolic volume

back 81

cardiac output

front 82

What is the term for an abnormally slow heart rate?

back 82

bradycardia

front 83

What does the Frank–Starling principle state?

back 83

There is a direct relationship between the EDV and the SV.

front 84

True/False. Bradycardia is the term used to describe a faster than normal heart beat.

back 84

False. Tachycardia is the term used to describe a faster than normal heart rate.

front 85

True/False. Starling’s law of the heart states that increasing the EDV leads to an increase in the stroke volume.

back 85

True

front 86

True/False. The AV valves are part of the heart’s fibrous skeleton.

back 86

True

front 87

True/False. The coronary arteries are branches of the superior vena cava.

back 87

False. The coronary arteries are the first branches of the aorta.

front 88

True/False. The pericardial sac is lined by the visceral pericardium.

back 88

False. The visceral pericardium covers or is attached directly to the heart.

front 89

Since the absolute refractory period in cardiac muscle is nearly as long as the contraction phase, _____ contractions cannot occur in normal cardiac muscle cells.

back 89

tetanic

front 90

The end-diastolic volume (EDV) is affected by the filling time and the _____. (use two words)

back 90

Venous return

front 91

Calcium entry into the cardiac muscle cell creates a _____ in the action potential that lasts about 175 msec.

back 91

Plateau

front 92

When _____ is released from autonomic neurons at the heart, the repolarization period is shortened and nodal cells reach threshold more quickly.

back 92

norepinephrine; NE

front 93

The blood vessels in the cardiovascular system are subdivided into three circuits known as the __________.

back 93

coronary, pulmonary, and systemic circuits

front 94

Which statement is true?

If the pacemaker of the heart stops, the AV node will take over.
The AV node can generate electrical impulses just as quickly as the SA node.
The autonomic nervous system has no effect on the heart.
If the pacemaker of the heart fails, then the heart will stop beating.

back 94

If the pacemaker of the heart stops, the AV node will take over.

front 95

The left atrium receives blood from the pulmonary circuit and empties it into the __________.

conus arteriosus
right atrium
left ventricle
right ventricle

back 95

left ventricle

front 96

The "double pump" function of the heart includes the right side, which serves as the __________ circuit pump, while the left side serves as the __________ pump.

pulmonary; hepatic portal
pulmonary; systemic
hepatic portal; cardiac
systemic; pulmonary

back 96

pulmonary; systemic

front 97

The coronary arteries emerge at the base of the __________.

pulmonary trunk
aorta
inferior vena cava
circumflex branch

back 97

aorta

front 98

Which blood vessels are known as exchange vessels?

veins
capillaries
arteries
All of the listed responses are correct.

back 98

capillaries

front 99

Blood from the coronary circuit is collected on the posterior aspect of the heart in a blood vessel known as the __________.

interventricular vein
great cardiac vein
circumflex branch
coronary sinus

back 99

coronary sinus

front 100

During the action potential in a contractile cardiac muscle cell, the opening of slow calcium channels results in the______ phase.

repolarization
depolarization
plateau
hyperpolarization

back 100

plateau

front 101

When deoxygenated blood leaves the right ventricle through a semilunar valve, it is forced into the __________.

aortic arch
lung capillaries
pulmonary arteries
pulmonary veins

back 101

pulmonary arteries

front 102

The passageways between cardiac muscle cells that allow ions to pass freely are called __________.

trabeculae carneae
anastomoses
gap junctions
desmosomes

back 102

gap junctions

front 103

Which of the following are characteristics of cardiac muscle cells?

nonstriated, multinucleated, and involuntary
striated, multinucleated, and voluntary muscle
striated, single central nucleus, and involuntary
striated, single central nucleus, and voluntary

back 103

striated, single central nucleus, and involuntary

front 104

Cardiac muscle tissue __________.

will not contract unless stimulated by autonomic nerves
will not contract unless stimulated by somatic motor neurons
is innervated mostly by neurons associated with the sympathetic division of the ANS
has its own intrinsic conduction system that can set the pace of the beating heart

back 104

has its own intrinsic conduction system that can set the pace of the beating heart

front 105

The right coronary artery generally gives rise to __________.

the posterior interventricular artery
the circumflex branch
the marginal branches
the marginal branches and the posterior interventricular artery
All the listed responses are correct.

back 105

the marginal branches and the posterior interventricular artery

front 106

The left coronary artery supplies blood to __________.

the circumflex branch
the anterior interventricular artery
the posterior descending artery
the anterior interventricular artery and the circumflex branch
All the listed responses are correct.

back 106

the anterior interventricular artery and the circumflex branch

front 107

What is the correct sequential path of a normal action potential in the heart?

SA node, AV node, bundle branches, AV bundle, Purkinje fibers
AV node, SA node, AV bundle, bundle of His
SA node, AV node, bundle of His, bundle branches, Purkinje fibers
SA node, AV bundle, AV node, Purkinje fibers

back 107

SA node, AV node, bundle of His, bundle branches, Purkinje fibers

front 108

Blood flows from the left atrium through the _______ to the left ventricle.

aortic valve
tricuspid valve
pulmonary valve
mitral valve

back 108

mitral valve

front 109

The P wave on the ECG indicates __________.

the electrical events spreading out over both atria
the spread of the electrical events down the interventricular septum
the contraction of the atria
the spread of electrical events over both ventricles

back 109

the electrical events spreading out over both atria

front 110

After the AV node is depolarized and the impulse spreads through the atria, there is a slight delay before the impulse spreads to the ventricles. The reason for this delay is to allow __________.

the ventricles to contract
a greater venous return
the atria to contract
the atria to fill with blood

back 110

the atria to contract

front 111

Valvular heart disease can be a result of __________.

congenital malformation
rheumatic fever
carditis
All of the listed responses are correct.

back 111

All of the listed responses are correct.

front 112

The QRS complex of the ECG appears as the __________.

ventricles repolarize
atria depolarize
ventricles depolarize
atria repolarize

back 112

ventricles depolarize

front 113

When a chamber of the heart fills with blood and prepares for the start of the next cardiac cycle, the chamber is in __________.

diastole
systole
ventricular ejection
isovolumetric contraction

back 113

diastole

front 114

During the isovolumetric contraction phase, the pressure in the _____ has to rise above aortic pressure for ventricular ejection to occur.

right atria
left atria
right ventricle
left ventricle

back 114

left ventricle

front 115

How would you define cardiac output?

the amount of blood pumped out of both ventricles in one minute
the amount of blood pumped out of the left ventricle in one minute
the amount of blood pumped out of the atria and ventricles in one minute
the end-diastolic volume plus the end-systolic volume

back 115

the amount of blood pumped out of the left ventricle in one minute

front 116

The amount of blood pumped out of each ventricle during a single beat is the __________.

end-systolic volume
cardiac output
end-diastolic volume
stroke volume

back 116

stroke volume

front 117

Under normal circumstances, the factors responsible for making delicate adjustments to the heart rate as circulatory demands change are __________.

cardiac output and stroke volume
nerve activity and muscular activity
autonomic activity and circulatory hormones
All of the listed responses are correct.

back 117

autonomic activity and circulatory hormones

front 118

The cardiac centers in the medulla oblongata monitor baroreceptors and chemoreceptors innervated by the __________.

glossopharyngeal N IX and vagus N X
accessory N XI and hypoglossal N XII
facial N VII and vesitbulocochlear N VIII
trochlear N IV and trigeminal N V

back 118

glossopharyngeal N IX and vagus N X

front 119

The difference between the end-diastolic volume (EDV) and the end-systolic volume (ESV) is the __________.

preload and afterload
cardiac output
stroke volume
cardiac reserve

back 119

stroke volume

front 120

Parasympathetic stimulation from the vagus nerve results in __________.

a decrease in heart rate
an increased heart rate and cardiac output
no effect on the heart rate
more forceful ventricular contractions

back 120

a decrease in heart rate

front 121

Which of the following statements is part of Starling's law of the heart?

A slightly larger and better-contracting heart will increase stroke volume.
An increase in venous return will increase blood flow into the heart.
The greater the ventricular stretch, the more forceful the contraction.
All of the listed responses are correct.

back 121

All of the listed responses are correct.

front 122

Physicians are interested in cardiac output because it provides a useful indication of __________.

valvular malfunctions
atrial efficiency in respect to time
ventricular efficiency over time
the amount of blood ejected by each ventricle

back 122

ventricular efficiency over time

front 123

Which heart chamber has the thickest muscular walls?

left ventricle
right ventricle
right atrium
left atrium

back 123

left ventricle

front 124

Which of the following medications serves as a positive treatment by interfering with the removal of calcium ions from the sarcoplasm of cardiac muscle cells?

digitalis
beta blockers
acetylcholine
verapamil

back 124

digitalis

front 125

What is the function of the chordae tendineae?

to anchor the aortic valve flaps and prevent backflow into the ventricles
to anchor the AV valve flaps and prevent backflow of blood into the atria
to anchor the bicuspid valve flaps and prevent backflow of blood into the ventricle
to anchor the semilunar valve flaps and prevent backward flow of blood into the ventricles

back 125

to anchor the AV valve flaps and prevent backflow of blood into the atria

front 126

Which of the following would NOT show up on an electrocardiogram?

conduction deficits
SA node damage
cardiac arrhythmias
murmurs

back 126

murmurs

front 127

During ventricular systole , what occurs when the pressure in the left ventricle rises above that in the left atrium?

The aortic valve closes.
The left AV valve opens.
All the valves close.
The left AV valve closes.

back 127

The left AV valve closes.

front 128

During ventricular systole, the blood volume in the atria is __________, and the volume in the ventricle is __________.

decreasing; decreasing
increasing; decreasing
increasing; increasing
decreasing; increasing

back 128

increasing; decreasing

front 129

Cardiac muscle cells are nourished via blood supply provided from the __________.

pulmonary circuit
coronary circuit
systemic circuit
All of the listed responses are correct

back 129

coronary circuit

front 130

Pulmonary arteries carry blood to the __________.

lungs
aorta
left atria
right atria

back 130

lungs

front 131

Which of the following statements is (are) true?

If you increase heart rate, then you will increase SV.
During ventricular systole, the papillary muscles contract to keep the AV valves shut and prevents them from swinging up into the atria.
If you increase ESV, then you will increase SV.
None of these statements is true.

back 131

During ventricular systole, the papillary muscles contract to keep the AV valves shut and prevents them from swinging up into the atria.

front 132

The heart sound associated with S2 occurs as the ventricles ____ and the semilunar valves ______.

relax; open
relax; close
contract; close
contract; open

back 132

relax; close

front 133

During isovolumetric systole, pressure is highest in the __________.

left atrium
pulmonary veins
aorta
left ventricle

back 133

left ventricle

front 134

Blood pressure in the large systemic arteries is greatest during __________.

isovolumetric systole
atrial systole
isovolumetric diastole
ventricular ejection

back 134

ventricular ejection

front 135

Decreased parasympathetic (vagus) stimulation to the heart results in a situation known as __________.

stenosis
bradycardia
carditis
tachycardia

back 135

tachycardia

front 136

Serious arrhythmias that reduce the pumping efficiency of the heart may indicate __________.

injury to the SA and AV nodes
variations in the ionic composition of the extracellular fluids
damage to the myocardium
All of the listed responses are correct.

back 136

All of the listed responses are correct.

front 137

During exercise, the most important control mechanism to increase cardiac output is __________.

increased end-systolic volume
increased acetylcholine release from the vagus nerve
increased body temperature
increased sympathetic activity to the ventricles

back 137

increased sympathetic activity to the ventricles

front 138

In the diastole phase of the ventricles, __________.

presystolic pressures are high
the ventricles are "resting"
the semilunar valves are open
the AV valves are closed

back 138

the ventricles are "resting"

front 139

Which of the following does NOT control the movement of blood through the heart?

the conducting system
size of the atria and ventricles
contraction of the myocardium
opening and closing of the valves

back 139

size of the atria and ventricles

front 140

Valvular malfunction in the heart __________.

interferes with ventricular contraction
interferes with movement of blood through the heart
increases the cardiac output
causes an increase in the amount of blood pumped out of each ventricle

back 140

interferes with movement of blood through the heart

front 141

If the bicuspid valve is defective and valvular regurgitation occurs, the end result is __________.

an insufficient amount of blood available to be moved into the aorta and systemic circulation
an overstretching of the left ventricle, causing a decrease in the force of contraction
gushing of blood into the left ventricle, causing excessive pressure
All of the listed responses are correct.

back 141

an insufficient amount of blood available to be moved into the aorta and systemic circulation

front 142

Which of the following is NOT a characteristic of cardiac muscle cells?

multiple nuclei
calcium entry is a trigger for contraction
mitochondria account for 25 percent of cell volume
short T tubules

back 142

multiple nuclei