Deck 13: The Cardiovascular System: Cardiac Function

Question 1

During isovolumetric contraction, which chamber has the greatest pressure?

A)right atrium
B)left ventricle
C)left atrium
D)right ventricle
E)AV bundle (bundle of His)

Answer 1

B

Question 2

Which of the following describes second- degree heart block?

A)There is a longer delay between atrial contraction and ventricular contraction.
B)The ventricles no longer contract.
C)Not every ventricular contraction is preceded by an atrial contraction.
D)The atria no longer contract.
E)Not every atrial contraction is followed by a ventricular contraction.

Answer 2

E

Question 3

During repolarization (phase 3)of a contractile cell action potential,

A)only sodium permeability is increased.
B)only calcium permeability is increased.
C)only potassium permeability is increased.
D)sodium and calcium permeability are both increased.
E)sodium and potassium permeability are both increased.

Answer 3

C

Question 4

An increase in venous return would result in a(n)

A)increased end- diastolic volume.
B)decreased end- systolic volume.
C)increased end- systolic volume.
D)increase mid- systolic volume.
E)decreased end- diastolic volume.

Question 5

The preload is approximately the same as the pressure.

A)aortic diastolic
B)end- systolic
C)atrial
D)aortic systolic
E)end- diastolic

Question 6

What structure separates the thoracic cavity from the abdominal cavity?

A)diaphragm
B)liver
C)intestines
D)lungs
E)heart

Question 7

In what phase is the cardiac cycle when the AV valves are open and semilunar valves are closed?

A)atrial contraction
B)ventricular filling
C)isovolumetric contraction
D)isovolumetric relaxation
E)ventricular ejection

Question 8

Which component of an ECG represents ventricular depolarization?

A)P wave
B)P- R interval
C)T wave
D)Q- T interval
E)QRS complex

Question 9

Which of the following best describes the effect of sympathetic activity on ventricular contractile cells?

A)The rates of contraction and relaxation both decrease, whereas the force of contraction increases.
B)The force of contraction increases, whereas the rates of contraction and relaxation are not affected.
C)The rates of contraction and relaxation and the force of contraction all increase.
D)The rate of contraction and the force of contraction both increase, whereas the rate of relaxation decreases.
E)The rates of contraction and relaxation both increase, whereas the force of contraction decreases.

Question 10

If both the SA node and the AV node fail, what would be the expected outcome of impulse rate within the heart?

A)The heart is autorhythmic therefore it continually beats even after death because death is defined as a lack of brain waves.
B)The sympathetic nervous system takes over and maintains normal heart rate.
C)The vagus nerve takes over and maintains a normal heart rate.
D)The rate would be 30- 40 beats per minute due to the concentration of pacemaker cells in the Purkinje fibers.
E)The individual would be in heart failure or have a myocardial infarction due to the lack of a beating heart.

Question 11

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.

A)arterial : venule
B)systemic : pulmonary
C)superior (upper body): inferior (lower body)
D)oxygenated : deoxygenated
E)pulmonary : systemic

Question 12

Which of the following is the correct conduction pathway through the heart?

A)SA node, Purkinje fibers, AV node, bundle of His, bundle branches
B)Purkinje fibers, bundle of His, bundle branches, SA node, AV node
C)SA node, AV node, bundle of His, bundle branches, Purkinje fibers
D)Bundle of His, bundle branches, Purkinje fibers, SA node, AV node
E)AV node, SA node, bundle branches, bundle of His, Purkinje fibers

Question 13

Which of the following statements best describes the function of the chordae tendineae?

A)The chordae tendineae act like a parachute and capture blood as it enters the right ventricle.
B)They pull downward on the valve cusps, thereby preventing the AV valves from being pushed into the atria (prolapsing).
C)The chordae tendineae generate autorhythmicity within the heart.
D)They open and close the AV valve due to the movement of the papillary muscle during contraction.
E)When the heart contracts, the chordate tendineae separate the flow of blood from the right and left sides of the heart.

Question 14

Which statement best describes why atrial depolarization is usually not detected on a normal ECG?

A)The electrodes cannot be placed high enough on the chest to detect the atria.
B)The atria do not contract only the AV valves open.
C)The voltage change in the atria is minimal and therefore does not register on an ECG.
D)It occurs at the same time as the QRS complex.
E)The atria are so small and the depolarization happens so quickly that it cannot be detected.

Question 15

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)?

A)chordae tendineae
B)arteries
C)apex
D)septum
E)valves

Question 16

What chamber empties into the aorta?

A)right atrium
B)left ventricle
C)left atrium
D)right ventricle
E)AV bundle (bundle of His)

Question 17

Closure of the atrioventricular valve occurs when

A)the papillary muscle contracts.
B)the valve contracts.
C)the atrium contracts.
D)pressure inside the ventricle is less than pressure inside the atrium.
E)pressure inside the ventricle is greater than pressure inside the atrium.

Question 18

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?

A)isovolumetric relaxation
B)ventricular ejection
C)isovolumetric contraction
D)ventricular filling
E)none

Question 19

Which of the following factors determines preload?

A)peripheral resistance and tension
B)parasympathetic activity of the ventricles
C)heart rate and venous return
D)the pressure in the aorta and the lungs
E)end- diastolic volume and end- systolic volume

Question 20

Which of the following describes the effect of end- diastolic volume on stroke volume?

A)A decrease in end- diastolic volume creates a vacuum drawing more blood into the ventricle increasing stroke volume.
B)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.
C)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.
D)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.
E)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.

Question 21

The SA node is innervated by the

A)sympathetic nervous system only.
B)somatic nervous system only.
C)parasympathetic nervous system only.
D)sympathetic and parasympathetic nervous systems.
E)sympathetic, parasympathetic, and somatic nervous systems.

Question 22

Under resting conditions, heart rate is primarily under the control of what control system?

A)the parasympathetic nervous system
B)intrinsic mechanisms
C)epinephrine
D)the sympathetic nervous system
E)the somatic nervous system

Question 23

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

A)between heartbeats.
B)of ventricular systole.
C)of ventricular diastole.
D)of atrial diastole.
E)of atrial systole.

Question 24

Which component of an ECG represents ventricular systole?

A)P wave
B)P- R interval
C)T wave
D)Q- T interval
E)QRS complex

Question 25

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.

A)platelets : leukocytes
B)erythrocytes : leukocytes
C)leukocytes : erythrocytes
D)erythrocytes : platelets

Question 26

The depolarization of the action potential in the pacemaker cells is driven by the rapid influx of ions through channels.

A)potassium : funny
B)sodium : funny
C)potassium : T- type calcium
D)sodium : T- type calcium
E)calcium : L- type calcium

Question 27

Which chamber of the heart has the thickest musculature?

A)left atrium
B)left ventricle
C)right atrium
D)right ventricle
E)Both ventricles have equal thickness and are thicker than the atria.

Question 28

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

A)nodal pathways
B)SA node
C)AV node
D)Purkinje fibers
E)bundle of His

Question 29

The volume of blood ejected from the ventricle with each contraction can be described by the equation

A)(ejection fraction)× (end- diastolic volume).
B)(end- systolic volume)- (stroke volume).
C)(stroke volume)- (end- diastolic volume).
D)(end- diastolic volume)- (end- systolic volume).
E)(pulse pressure)- (end- diastolic volume).

Question 30

Which of the following components of an ECG represents atrial depolarization?

A)P wave
B)QRS complex
C)T wave
D)PQ interval
E)TQ segment

Question 31

What channels open during the plateau phase of the cardiac contractile cell action potential?

A)potassium channels
B)T- type calcium channels
C)funny channels
D)L- type calcium channels
E)voltage- gated sodium channels

Question 32

In what phase is the cardiac cycle when the semilunar valves are open and AV valves are closed?

A)atrial contraction
B)ventricular filling
C)isovolumetric contraction
D)isovolumetric relaxation
E)ventricular ejection

Question 33

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?

A)arteries, veins, venules, arterioles, capillaries
B)arterioles, arteries, capillaries, venules, veins
C)veins, capillaries, venules, arterioles, arteries
D)veins, venules, capillaries, arterioles, arteries
E)arteries, arterioles, capillaries, venules, veins

Question 34

A decrease in afterload will lead to which of the following?

A)increased stroke volume
B)decreased cardiac output
C)decreased heart rate
D)increased heart rate
E)decreased stroke volume

Question 35

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?

A)Purkinje fibers
B)sinoatrial node
C)ventricles
D)atrioventricular node
E)conduction pathway

Question 36

Where is the SA node located?

A)right atrium
B)left ventricle
C)left atrium
D)right ventricle
E)AV bundle (bundle of His)

Question 37

Which statement best describes parallel flow in the circulatory system?

A)In the systemic circuit blood flows from one organ directly to the next, hence in parallel.
B)Parallel flow refers to the flow of blood just to the heart itself, which keeps it oxygenated at all times.
C)Parallel flow refers to deoxygenated blood only and not to oxygenated blood.
D)Parallel flow refers to the flow of electrical impulses in the heart.
E)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.

Question 38

Which of the following decreases heart rate?

A)increase in parasympathetic activity
B)increase in stroke volume
C)increase in venous pressure
D)increase in filling time
E)increase in sympathetic activity

Question 39

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

A)T = PR/2.
B)CO = HR × SV.
C)SV = EDV - ESV.
D)EF = EDV - ESV.
E)BP - PR × VL.

Question 40

During which phase of the cardiac cycle are all four heart valves open?

A)isovolumetric relaxation
B)isovolumetric contraction
C)ventricular filling
D)ventricular ejection
E)none

Question 41

Which component of an ECG represents ventricular diastole?

A)T wave
B)P- R interval
C)Q- T interval
D)T- Q segment
E)QRS complex

Question 42

Which channel type allows calcium movement into the cell during the late spontaneous depolarization in autorhythmic cells?

A)potassium channels
B)T- type calcium channels
C)funny channels
D)L- type calcium channels
E)voltage- gated sodium channels

Question 43

The small increase in ventricular pressure observed late in diastole is caused by

A)ventricular contraction.
B)blood moving into the atria from vena cava.
C)atrial contraction.
D)ventricular relaxation.
E)atrial relaxation.

Question 44

Which component of an ECG represents atrial depolarization?

A)P wave
B)P- R interval
C)T wave
D)Q- T interval
E)QRS complex

Question 45

Opening of what channels is responsible for the depolarization phase of the cardiac contractile cell action potential?

A)potassium channels
B)T- type calcium channels
C)funny channels
D)L- type calcium channels
E)voltage- gated sodium channels

Question 46

Which of the following is NOT a part of the excitation- contraction coupling in cardiac muscle?

A)An action potential travels along transverse tubules.
B)Calcium binds to calmodulin in the cytosol.
C)Calcium channels in the sarcoplasmic reticulum open, allowing calcium ions to enter the cytosol.
D)Calcium channels in the plasma membrane open, allowing calcium ions to enter the cell.
E)Calcium opens calcium channels in the sarcoplasmic reticulum.

Question 47

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

A)R- R interval
B)P wave
C)QRS complex
D)T wave
E)P- Q interval

Question 48

Conduction through which of the following is slow to allow atria to contract before the ventricles?

A)SA node
B)AV bundle (bundle of His)
C)AV node
D)Purkinje fibers
E)atria

Question 49

The P wave of the electrocardiogram is created by

A)atrial repolarization.
B)atrial depolarization.
C)ventricular depolarization.
D)ventricular repolarization.
E)atrial hyperpolarization.

Question 50

Given end- diastolic volume = 130 mL and end- systolic volume = 50 mL, what is the stroke volume and ejection fraction?

A)SV = 180 mL, EF = 0.38
B)SV = 80 mL, EF = 0.61
C)SV = 80 mL, EF = 0.38
D)SV = 180 mL, EF = 0.61
E)SV = 50 mL, EF = 0.61

Question 51

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.

A)neurogenic
B)intrinsic
C)myogenic
D)voluntary
E)extrinsic

Question 52

Which chamber is connected to the pulmonary arteries?

A)right atrium
B)left ventricle
C)left atrium
D)right ventricle
E)AV bundle (bundle of His)

Question 53

During isovolumetric relaxation,

A)the AV and semilunar valves are closed and ventricular pressure is increasing.
B)the AV valves are open, the semilunar valves are closed, and ventricular pressure is decreasing.
C)the AV and semilunar valves are closed and ventricular pressure is decreasing.
D)the AV and semilunar valves are open and ventricular pressure is decreasing.
E)the AV and semilunar valves are open and ventricular pressure is increasing.

Question 54

Blood supply to the heart comes from

A)aorta.
B)blood within the ventricles.
C)blood within the atria.
D)cerebral arteries.
E)coronary arteries.

Question 55

The increased aortic pressure that occurs during systole reflects a(n)

A)decreased volume of blood within the aorta.
B)decreased resistance of the vasculature.
C)decreased stiffness of the aorta.
D)increased volume of blood in the aorta.
E)increased resistance of the vasculature.

Question 56

In an ECG recording, the RR interval is 0.5 seconds. What is the heart rate?

A)30 beats/min
B)120 beats/min
C)60 beats/min
D)100 beats/min
E)50 beats/min

Question 57

Blood returns to the left atrium via what blood vessels?

A)coronary artery
B)aorta
C)iliac vein
D)superior and inferior vena cavae
E)pulmonary veins

Question 58

Which of the following variables is NOT an intrinsic factor that alters cardiac function?

A)preload
B)atrial pressure
C)Starling's law
D)hormonal stimulation
E)end- systolic volume

Question 59

The opening and closure of the atrioventricular and semilunar valves is driven by

A)contraction of muscles attached to the valves.
B)contraction of the ventricle and atria that pull the valves into place.
C)contraction and relaxation of the valve.
D)differences in pressure across the valve.
E)contraction of the valve.

Question 60

Which of the following is responsible for the repolarization of pacemaker cells?

A)a decrease in PNa
B)a decrease in PK
C)an increase in PCa
D)an increase in PNa
E)an increase in PK

Question 61

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

A)epicardium, myocardium, and endothelium
B)endothelium, epicardium, and myocardium
C)endothelium, myocardium, and epicardium
D)myocardium, epicardium, and endothelium
E)myocardium, endothelium, and epicardium

Question 62

Which of the following ion channels does NOT participate in the contractile cell action potential?

A)type L calcium channels
B)inward rectifying potassium channels
C)delayed rectifying potassium channels
D)voltage- gated sodium channels
E)type T calcium channels

Question 63

An increase in heart rate can be mediated through which of the following?

A)a decrease in parasympathetic nervous activity only
B)a decrease in sympathetic activity only
C)an increase in sympathetic activity only
D)an increase in parasympathetic activity and a decrease in sympathetic activity
E)a decrease in parasympathetic activity and an increase in sympathetic activity

Question 64

The second heart sound coincides with the beginning of which period in the cardiac cycle?

A)atrial contraction
B)ventricular filling
C)isovolumetric contraction
D)isovolumetric relaxation
E)ventricular ejection

Question 65

What structure provides the pathway for the movement of electrical current between the cells of the conduction pathway and the ventricular muscle fibers?

A)funny channels
B)desmosomes
C)potassium channels
D)sodium channels
E)gap junctions

Question 66

What is the pacemaker of the heart?

A)nodal pathways
B)SA node
C)bundle of His
D)AV node
E)Purkinje fibers

Question 67

Whereas the contractile activity of skeletal muscle is called , that of cardiac muscle is because the contraction originates within the musculature itself.

A)somatic : autorhythmic
B)voluntary : involuntary
C)extrinsic : intrinsic
D)neurogenic : myogenic
E)somatic : autonomic

Question 68

The increase in ventricular volume early in diastole reflects the

A)back- flow of blood from the aorta.
B)relaxation of the ventricle.
C)contraction of the atria moving blood into the ventricle.
D)passive movement of blood through the atrium and into the ventricle.
E)increased stiffness of the heart.

Question 69

Which component of an ECG represents ventricular repolarization?

A)P wave
B)P- R interval
C)T wave
D)Q- T interval
E)QRS complex

Question 70

Which of the following components of an ECG represents ventricular depolarization?

A)P wave
B)QRS complex
C)T wave
D)PQ interval
E)TQ segment

Question 71

Which heart structure receives blood from the pulmonary veins?

A)right atrium
B)left ventricle
C)left atrium
D)right ventricle
E)AV bundle (bundle of His)

Question 72

Which of the following is a FALSE statement about sympathetic activity to the SA node?

A)The rate of spontaneous depolarization is increased.
B)Norepinephrine binds to beta1 adrenergic receptors.
C)Potassium channel closing is enhanced.
D)cAMP levels in the pacemaker cells increases.
E)Funny channel opening is enhanced.

Question 73

Which of the following would NOT result from an increase in ventricular contractility?

A)increased ejection fraction
B)increased proportion of end- diastolic volume that is ejected
C)increased stroke volume
D)decreased end- systolic volume
E)decreased end- diastolic volume

Question 74

Which channel type is responsible for ion movement during the depolarization phase of the autorhythmic cell action potential?

A)potassium channels
B)T- type calcium channels
C)funny channels
D)L- type calcium channels
E)voltage- gated sodium channels

Question 75

Starling curves plot against _.

A)cardiac output : end- diastolic volume
B)heart rate : end- diastolic volume
C)stroke volume : end- diastolic volume
D)heart rate : end- systolic volume
E)stroke volume : end- systolic volume

Question 76

The Q- T interval is the time from the onset of the QRS complex to the end of the T wave which measures

A)the time of atrial diastole.
B)the amount of time between each heartbeat.
C)the time of ventricular systole.
D)the time of atrial systole.
E)the time of ventricular diastole.

Question 77

Which component of an ECG represents the AV nodal conduction time?

A)T wave
B)QRS complex
C)P- R interval
D)T- Q segment
E)Q- T interval

Question 78

Blood is ejected from the left ventricle once pressure within the

A)ventricle is greater than pressure within the aorta.
B)ventricle is less than pressure within the aorta.
C)ventricle is greater than pressure within the pulmonary artery.
D)ventricle is less than pressure within the pulmonary artery.
E)muscles of the pulmonary semilunar valve relax.

Question 79

Cardiac output is determined by what two variables?

A)preload and afterload
B)heart rate and stroke volume
C)heart rate and ejection fraction
D)end- diastolic volume and end- systolic volume
E)stroke volume and ejection fraction

Question 80

The R- R interval is the time between the peaks of two successive QRS complexes and represents

A)atrial systole.
B)the amount of time between heartbeats.
C)ventricular diastole.
D)atrial diastole.
E)ventricular systole.