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Physiology 412G > Cardiovascular -- Practice Questions > Flashcards

Cardiovascular -- Practice Questions Flashcards

1
Q

The cardiovascular system solves the problem of __________ in
_____________.
a) blood flow — muscle cells
b) transport — unicellular organisms
c) diffusion — multicellular organisms
d) oxygen transport — acid-base regulation

A

diffusion – multicellular organisms

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2
Q

__________is the volume of blood occupied by __________ .
a) Hematocrit — erythrocytes
b) Albumin — protein
c) Fuzzy layer — lymphocytes
d) Cardiac output — plasma

A

Hematocrit – erythrocytes

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3
Q

Which of the following statements is correct?
a) The AV valves open when the atria contract.
b) The aortic and AV valves open simultaneously.
c) The AV valves open when the ventricles contract.
d) The AV valves close when the ventricles contract.

A

The AV valves close when the ventricles contract

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4
Q

In contrast to arterial vessels, veins have:
a) thinner walls.
b) more smooth muscle.
c) higher resistance.
d) thicker endothelium.

A

Thinner walls

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5
Q

Which of the following is a step in the process of cardiomyocyte contraction?
a) End-plate depolarization.
b) L-type Ca 2+ channels open.
c) Sarcoplasmic reticulum depolarization.
d) SR Na +-Ca 2+ exchanger activates.

A

L-type Ca2+ channels open

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6
Q

The amplitude of the cytosolic Ca 2+ concentration during a cardiomyocyte
contraction depends on:
a) Ca 2+-induced Ca 2+ release from the SR.
b) the amplitude of the action potential.
c) Ca 2+ entry via the SR Ca 2+ ATPase.
d) the opening of T-type Ca 2+ channels.

A

Ca2+ -induced Ca2+ release from the SR

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7
Q

Which of the following is not a likely consequence of increased sympathetic
stimulation to the SA node?
a) Steeper phase 4 depolarization slope.
b) Increased Ca 2+ influx.
c) Decreased resting membrane potential.
d) Decreased action potential threshold.

A

Decreased resting membrane potential

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8
Q

The P and QRS waves of a normal ECG result from ____________ and
____________, respectively.
a) atrial repolarization — ventricular repolarization
b) atrial depolarization — ventricular depolarization
c) SA node depolarization — AV node depolarization
d) SA node repolarization — AV node repolarization

A

atrial depolarization – ventricular depolarization

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9
Q

Which of the following events is not a part of the cardiac cycle phases in normal
subjects?
a) Atrioventricular node initiates atrial contraction.
b) Ventricular contraction while inlet and outlet valves are closed.
c) Opening of outlet valves during ventricular contraction.
d) Atrial contraction during ventricular filling.

A

Atrioventricular node initiates atrial contraction

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10
Q

A key difference between the cardiac cycles of the left and right ventricles is that:
a) the two ventricles have the same stroke volume.
b) the left ventricle has a higher contraction frequency.
c) The right ventricle has a smaller stroke volume.
d) the right ventricle produces lower pressures.

A

The right ventricle produces lower pressures

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11
Q

In one normal cardiac cycle, the ___________ occurs ______________.
a) QRS wave — before atrial contraction
b) opening of AV valves — before atrial contraction
c) first heart sound — during isovolumetric relaxation
d) isovolumetric contraction — during ventricular filling

A

opening of AV valves – before atrial contraction

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12
Q

What factor contributes to the increase in force production when cardiac muscle
sarcomere length increases from 1.8 to 2.2 um?
a) Increased SR Ca 2+ pump activity.
b) Loss of thick and thin filament overlap.
c) Decreased probability of cross-bridge formation.
d) Increased myofilament Ca 2+ sensitivity.

A

Increased myofilament Ca2+ sensitivity

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13
Q

According to Frank-Starling law of the heart, increased end-diastolic volume will:
a) increase extracellular Ca 2+ release.
b) decrease heart rate.
c) increase systolic ventricular pressure.
d) decrease myofilament Ca 2+ sensitivity.

A

increase systolic ventricular pressure

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14
Q

In the ________, blood flow is continuous and blood pressure approaches 0 mm Hg.
a) veins
b) capillaries
c) arterioles
d) aorta

A

veins

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15
Q

Change of which of the following factors would have the greatest effect on vascular
resistance?
a) Hematocrit
b) Blood density
c) Hydrostatic pressure
d) Vessel diameter

A

Vessel diameter

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16
Q

Which of the following statements about resistances arranged in parallel is correct?
a) Each resistance has a different flow.
b) Total flow is proportional to the length of the tubes.
c) Total resistance is less than the individual resistances.
d) All resistances are the same.

A

Total resistance is less than the individual resistances

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17
Q

The aorta and other large arteries are very compliant. How does this property influence blood flow?
a) It increases the work of the heart.
b) It decreases peripheral vascular resistance.
c) It increases systolic pressure.
d) It improves blood flow during diastole.

A

It improves blood flow during diastole

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18
Q

Systemic blood pressure determines the _______________, the force that drives filtration out of the capillaries under normal conditions.
a) end-diastolic pressure
b) capillary hydrostatic pressure
c) plasma oncotic pressure
d) interstitial oncotic pressure

A

capillary hydrostatic pressure

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19
Q

Which of the following is not a function of veins?
a) Serve as a blood reservoir.
b) Return blood back to the heart.
c) Regulate plasma oncotic pressure.
d) Change capillary hydrostatic pressure.

A

Regulate plasma oncotic pressure

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20
Q

Which of the following statements about the determinants of cardiac output is correct?
a) Venous return determines afterload.
b) Acetylcholine increases cardiac contractility.
c) Arterial pressure determines preload.
d) Heart rate can influence preload.

A

Heart rate can influence preload

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21
Q

Increased firing rate of aortic baroreceptors:
a) causes an increase in blood pressure.
b) follows blood pressure increases.
c) causes an increase in heart rate.
d) leads to vasoconstriction and tachycardia.

A

follows blood pressure increases.

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22
Q

An increase in end-diastolic volume will increase cardiac output via:
a) the Frank-Starling mechanism.
b) an increase in afterload.
c) a positive inotropic effect.
d) a positive chronotropic effect.

A

the Frank-Starling mechanism.

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23
Q

The extrinsic regulation of cardiac output includes the following factors, except:
a) catecholamines.
b) sympathetic drive.
c) thyroid hormones.
d) preload.

A

preload

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24
Q

Which of the following statements about local myogenic regulation of blood flow is correct?
a) It is due to endothelium-derived vasodilators.
b) It results from local interstitial hypoxia.
c) It is a response to transmural pressure in arterioles.
d) It is caused by a local increase in adenosine concentration.

A

It is a response to transmural pressure in arterioles.

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25
Q

The renin-angiotensin-aldosterone:
a) increases sympathetic activity.
b) is activated by low blood pressure.
c) results in loss of extracellular water.
d) decreases cardiac afterload.

A

is activated by low blood pressure.

26
Q

__________ and __________ are called coupling factors.
a) Afterload — heart rate
b) Inotropic state — heart rate
c) Preload — afterload
d) Preload — Inotropic state

A

Preload – afterload

27
Q

Which of the following statements about vascular compliance is correct?
a) It is equal to the change in volume for a given change in pressure.
b) Arterial compliance is 20 times greater than venous compliance.
c) Venous compliance increases when blood volume decreases.
d) Venous compliance is equal to cardiac compliance.

A

It is equal to the change in volume for a given change in pressure.

28
Q

A vascular function curve will:
a) have a lower mean systemic filling pressure after vasoconstriction.
b) shift up and left after severe hemorrhage.
c) have a steeper slope after venous constriction.
d) shift to the right and up with a blood transfusion.

A

shift to the right and up with a blood transfusion

29
Q

Under steady state conditions, the cardiac and vascular function curves:
a) intersect at the steady state point.
b) relate cardiac output to arterial pressure.
c) are fixed and cannot be changed.
d) cannot change simultaneously.

A

intersect at the steady state point.

30
Q

The cardiovascular system includes the following components, except:
a) cardiac output.
b) endocrine system.
c) total peripheral resistance.
d) vasomotor control.

A

endocrine system.

31
Q

The cardiovascular response to exercise:
a) includes local control of systemic circulation.
b) resembles the fight-or-flight response.
c) results in decreased stroke volume.
d) decreases oxygen consumption in muscle.

A

resembles the fight-or-flight response.

32
Q

Which of the following statements about the hematocrit is correct?
a. It represents red blood cell content.
b. It is normally higher in women than in men.
c. It depends on hepatic blood production.
d. It is the top cell layer after blood centrifugation.

A

It represents red blood cell content

33
Q

Blood clotting is initiated by:
a. increased velocity of capillary blood flow.
b. contact with positively charged epithelial surfaces.
c. increased interstitial tissue pressure.
d. contact with collagen underneath endothelial cells.

A

Contact with collagen underneath endothelial cells

34
Q

____________ receives blood from the systemic circulation; ____________ receives blood from the pulmonary circulation.
a. Left atrium — right ventricle
b. Right atrium — right ventricle
c. Right atrium — left atrium
d. Left atrium — left ventricle

A

Right atrium — left atrium

35
Q

The right ventricle has ____________ walls than the left ventricle. Therefore, the right ventricle produces ____________ pressure than the left ventricle.
a. less — less
b. thicker — more
c. longer — more
d. thinner — less

A

thinner — less

36
Q

Which of the following statements about capillaries is true?
a. Capillary walls have a thick smooth muscle layer.
b. Capillary walls have endothelial cells.
c. Capillary walls have elastic tissue.
d. Resistance is highest in the capillary beds.

A

Capillary walls have endothelial cells

37
Q

In contrast to skeletal muscle fibers, cardiomyocytes:
a. are short and branched.
b. have multiple nuclei per cell.
c. are innervated by the somatic motor system.
d. have sarcomeres.

A

are short and branched.

38
Q

During a cardiomyocyte contraction, which of the following steps would decrease the cytosolic calcium concentration faster?
a. Opening of ryanodine receptors.
b. Decrease myosin ATPase activity.
c. Phospholamban phosphorylation.
d. Opening of L-type calcium channels.

A

Phospholamban phosphorylation

39
Q

Which of the following is an early step in cardiomyocyte contraction?
a. calcium influx via L-type calcium channels.
b. depolarization of the sarcoplasmic reticulum.
c. increased calcium ATPase activity.
d. calcium binding to tropomyosin.

A

calcium influx via L-type calcium channels

40
Q

The positive chronotropic effect of increased sympathetic activity is due to:
a. faster phase 0 depolarization.
b. faster phase 4 depolarization.
c. longer phase 2 plateau.
d. longer phase 3 repolarization.

A

faster phase 4 depolarization.

41
Q

Adrenergic stimulation stimulates the calcium pumps in the sarcoplasmic reticulum of ventricular cardiomyocytes. This effect will:
a. decrease calcium influx.
b. lengthen the action potential.
c. decrease calcium release.
d. shorten their contractions.

A

shorten their contractions.

42
Q

The ECG tracing above was obtained from a healthy 25-year-old male subject. In this tracing, the interval between R waves (RR interval) fluctuates between 0.8 and 0.92 seconds. Therefore, you calculate that the subject’s heart rate (beats per minute, bpm) is around:
a. 80 bpm.
b. 55 bpm.
c. 70 bpm.
d. 95 bpm.

A

70 bpm.

43
Q

A healthy 40-year-old female subject comes to the exercise laboratory. Her heart rate at rest is about 65 beats/minute: systole lasts 350 msec, diastole lasts 570 msec. Four minutes after starting an interval exercise program on a stationary bicycle, her heart rate is 130 beats/minute. You estimate that the duration of:
a. systole decreases to less than 100 msec.
b. systole increases to about 390 msec.
c. diastole stays about the same.
d. diastole decreases to about 200 msec.

A

diastole decreases to about 200 msec.

44
Q

When end-diastolic volume increases, stroke volume ______________ because
________________.
a. increases —- myofilament calcium sensitivity increases
b. increases —- thin and thick filament overlap improves
c. decreases — cytosolic calcium decreases
d. does not change — end-systolic volume is the same

A

increases — myofilament calcium sensitivity increases.

45
Q

According to Poiseuille’s law, if the hematocrit increases, vascular resistance:
a. decreases.
b. increases.
c. does not change.
d. cannot be determined.

A

increases.

46
Q

The total resistance in a vascular bed with vessels of the same diameter and length arranged in series is:
a. not affected by autonomic factors.
b. inversely proportional to the number of vessels.
c. less than each individual resistance.
d. more than each individual resistance.

A

less than each individual resistance.

47
Q

A woman has diastolic and systolic blood pressures of 70, and 120 mm Hg, respectively. Her pulse pressure is close to:
a. 50 mm Hg
b. 87 mm Hg
c. 95 mm Hg
d. 103 mm Hg

A

50 mmHg.

48
Q

Starling forces (see above) describe the relationship of the forces that influence fluid movement across the capillary endothelium. If the protein content of plasma decreases significantly, that is likely to result in:
a. increased capillary hydrostatic pressure.
b. high blood pressure.
c. decreased interstitial hydrostatic pressure.
d. generalized edema.

A

generalized edema.

49
Q

Which of the following conditions would increase net filtration pressure in a systemic capillary?
a. Left ventricular failure.
b. Aortic stenosis (narrowing).
c. Stenosis (narrowing) of the right AV valve.
d. Decreased arterial blood pressure.

A

Stenosis (narrowing) of the right AV valve.

50
Q

An instantaneous and simultaneous increase in cardiac afterload and preload is likely to result in:
a. an increase in cardiac output.
b. an increase in blood pressure.
c. a decrease in heart rate.
d. cannot be determined.

A

cannot be determined.

51
Q

When blood volume is higher than normal, an increase in venous return:
a. increases heart rate.
b. decreases heart rate.
c. decreases stroke volume.
d. constricts capacitance vessels.

A

increases heart rate.

52
Q

Which of the following is one way the sympathetic nervous system influences cardiac function?
a. It slows the pacemaker current.
b. It decreases end-diastolic volume.
c. It has a negative inotropic effect.
d. It has a positive chronotropic effect.

A

It has a positive chronotropic effect.

53
Q

The pulse pressure of a healthy student is more likely to be:

95 mm Hg
5 mm Hg
30 mm Hg
120 mm Hg

A

30 mmHg.

54
Q

A healthy young student used an elliptical trainer for 40 minutes at the gym. Although the workload remained constant, the student’s heart rate rose to 150 beats per minute during the first 5 minutes, stayed at that level for the next 25 minutes, and then started to rise. It was 180 beats per minute at the end of the exercise period. What was the time interval between QRS complexes when the student’s heart rate was 180 beats per minute?

3333 ms
3.3 ms
333 ms
33 ms

A

333 ms

55
Q

Peripheral edema could be caused by:

blocked lymphatic vessels.
slowed heart rate.
increased plasma albumin concentration.
decreased capillary blood pressure.

A

blocked lymphatic vessels

56
Q

In cardiac pacemaker cells, the L-type calcium channels:

pump Ca2+ ions into the sarcoplasmic reticulum.
open during diastole.
are located in the cell membrane.
close when the membrane potential rises above threshold.

A

are located in the cell membrane.

57
Q

Beta-blockers inhibit the activity of beta-adrenergic receptors and change the function of the heart by:

increasing heart rate and decreasing contractility.
decreasing heart rate and increasing contractility.
decreasing heart rate and decreasing contractility.
increasing heart rate and increasing contractility.

A

decreasing heart rate and decreasing contractility.

58
Q

A physiology student is sitting still in a cold igloo. After 30 minutes, the student stands up, walks slowly around the igloo, and suddenly starts to shiver. The student started to shiver soon after walking because:

blood moved to the periphery, became cold, and chilled the core when it returned to the chest.
the ATP concentration in the skeletal muscles had dropped to zero.
the ventricles started to fibrillate.
the atria started to fibrillate.

A

blood moved to the periphery, became cold, and chilled the core when it returned to the chest.

59
Q

A young healthy student used an elliptical trainer for 40 minutes at the gym. Although the workload remained constant, the student’s heart-rate rose to 150 beats per minute during the first 5 minutes, stayed at that level for the next 25 minutes and then started to rise. It was 180 beats per minute at the end of the exercise period. The student’s heart rate is more likely to have risen during the last 10 minutes of exercise because the:

atrial cells were fatigued.
lungs were becoming congested.
extracellular Ca2+ concentration had increased.
hematocrit increased due to sweating.

A

hematocrit increased due to sweating.

60
Q

A physiology student is sitting still in a cold igloo. After 30 minutes, the student stands up, walks slowly around the igloo, and suddenly starts to shiver. The student preserved the body’s core temperature while sitting by:

depressing the Frank-Starling mechanism.
increasing the resistance of arterioles in the arms and legs.
decreasing the extracellular Ca2+ concentration.
relaxing smooth muscles in the peripheral circulation.

A

increasing the resistance of arterioles in the arms and legs.

61
Q

A newly discovered drug binds to myosin molecules in cardiac muscle (and nowhere else), and increases the probability that myosin molecules in ventricular cells will bind to actin filaments when the intracellular Ca2+ concentration rises. The drug is being tested as a potential therapy for patients with heart failure.

This drug might help people who have low cardiac output by:

increasing the isovolumic contraction time.
increasing the force developed by ventricular cells.
increasing heart rate.
increasing peripheral resistance.

A

increasing the force developed by ventricular cells.

62
Q

A newly discovered drug binds to myosin molecules in cardiac muscle (and nowhere else), and increases the probability that myosin molecules in ventricular cells will bind to actin filaments when the intracellular Ca2+ concentration rises. The drug is being tested as a potential therapy for patients with heart failure.

The increased binding of cardiac myosin molecules to actin might prevent the drug from being a useful treatment by:

accelerating heart rate.
decreasing the resistance of capillaries.
slowing ventricular relaxation.
decreasing the duration of systole.

A

slowing ventricular relaxation.

Physiology 412G (7 decks)

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