Deck 10: Circulatory Responses to Exercise

Question 1

The fact that an increase in end-diastolic ventricular volume increases the stroke volume of the heart is an illustration of the

A)influence of the parasympathetic nervous system on cardiac output.
B)Frank-Starling law of the heart.
C)influence of atrioventricular node on cardiac output.
D)influence of blood pressure on cardiac output.

Answer 1

B

Question 2

The relationship between cardiac output and metabolic rate is

A)linear.
B)curvilinear.
C)exponential.
D)there is no relationship between cardiac output and metabolic rate.

Answer 2

A

Question 3

In order to meet the increased oxygen demands of muscle during exercise,two major adjustments in blood flow must be made:

A)an increase in heart rate and diastolic blood pressure.
B)an increase in blood flow to both the gut and brain.
C)an increase in cardiac output and a redistribution of blood flow from inactive tissues to skeletal muscles.
D)an increase in muscle blood flow and an increase in blood flow to the liver.

Answer 3

C

Question 4

The cardiovascular control center is located in the

A)medulla oblongata.
B)carotid sinus.
C)cerebrum.
D)atria of the heart.

Question 5

All gas exchange between the vascular system and tissues occurs in

A)venules.
B)capillaries.
C)arterioles.
D)veins.

Question 6

The decrease in maximal heart rate with age in adults can be estimated via

A)HR max = 220 - age.
B)HR max = 200 - age.
C)HR max = 210 - age.
D)HR max = 205 - age.

Question 7

An increase in parasympathetic outflow to the heart results in

A)an increase in HR.
B)a decrease in HR.
C)a small increase in arterial blood pressure.
D)a small increase in arterial blood pressure followed by an increase in HR.

Question 8

The muscle of the heart is referred to as the

A)pericardium.
B)myocardium.
C)epicardium.
D)endocardium.

Question 9

The primary purpose of the cardiovascular system is to

A)maintain constant carbon dioxide levels in the body.
B)deliver adequate levels of oxygen and remove wastes from body tissues.
C)remove metabolic wastes from kidney during exercise.
D)none of the above answers are correct.

Question 10

During exercise,the time spent in diastole and systole

A)remains unchanged.
B)is decreased equally.
C)is decreased,with the greatest decrease occurring in diastole.
D)is increased.

Question 11

Backflow of blood from the arteries into the ventricles is prevented by the

A)semilunar valves.
B)bicuspid valve.
C)atrioventricular valves.
D)coronary valves.

Question 12

In most subjects,stroke volume continues to increase during incremental exercise up to approximately

A)20% of VO₂ max.
B)40% of VO₂ max.
C)75% of VO₂ max.
D)90% of VO₂ max.

Question 13

The __________ represents ventricular repolarization during a recording of the electrical activity (i.e. ,ECG)of the heart.

A)P wave
B)QRS complex
C)T wave
D)R wave

Question 14

The contraction phase of the heart is called

A)diastole.
B)atrial contraction.
C)systole.
D)the cardiac cycle.

Question 15

In a healthy heart,the time spent in systole is generally

A)longer than diastole.
B)equal to diastole.
C)shorter than diastole.
D)three times longer than diastole.

Question 16

The normal pacemaker of the heart is the

A)atrioventricular node.
B)sinoatrial node.
C)A-V node.
D)S-V node.

Question 17

The difference between systolic and diastolic blood pressure is called the

A)pulse pressure.
B)mean arterial blood pressure.
C)brachial pressure.
D)double product.

Question 18

The most important variable that determines resistance to blood flow is

A)the viscosity of blood.
B)the length of the blood vessel.
C)the diameter of the vessel.
D)blood pressure.

Question 19

Electrical impulses are conducted between heart muscle cells by

A)intercalated discs.
B)intermediate junctions.
C)active transport of sodium between cells.
D)Purkinje fibers.

Question 20

The increase in cardiac output that occurs during exercise is due to

A)both an increase in mean arterial pressure and a decrease in vascular resistance.
B)a decrease in vascular resistance only.
C)an increase in mean arterial blood pressure only.
D)an increase in heart rate and a decrease in mean arterial blood pressure.

Question 21

Most of the increase in mean arterial blood pressure that occurs during dynamic (isotonic)incremental exercise is due to

A)an increase in diastolic blood pressure.
B)the increase in systolic blood pressure.
C)both an increase in diastolic and systolic blood pressure.
D)none of the above answers are correct

Question 22

Skeletal and cardiac muscle are similar in which of the following ways?

A)both muscles contain type I,IIa,and IIx fibers
B)both muscles are under voluntary control
C)both muscles contain fibers that are branched
D)both muscles are composed of striated fibers containing actin and myosin

Question 23

According to the Fick equation,if cardiac output doubles during exercise and the arterial-mixed venous oxygen difference remains constant,body oxygen consumption would

A)remain constant
B)decrease by 50%
C)increase by 100%
D)none of the above answers are correct

Question 24

Which of the following is the correct order of events pertaining to contraction of the left ventricle?

A)The bundle branches depolarize,the ventricle contracts,the ventricular pressure increases,and blood exits the ventricle.
B)The aortic volume increases,the ventricular pressure increases,the ventricle contracts,the bundle branches depolarize.
C)The ventricular pressure increases,the bundle branches depolarize,the aortic volume increases,the ventricle contracts.
D)The bundle branches depolarize,the ventricular pressure increases,the ventricle contracts,the aortic volume increases.

Question 25

In general,heart rate increases in direct proportion to the metabolic rate during exercise.

Question 26

The central command theory of cardiovascular control states that the initial signal to the cardiovascular system at the beginning of exercise comes from higher brain centers.

Question 27

Which of the following statement about beta-adrenergic blocking medications are true?

A)beta blocking drugs reduce heart rate during exercise.
B)beta blockade reduces the vigor of ventricular contraction.
C)beta blocking drugs compete with epinephrine and norepinephrine for beta-adrenergic receptors in the heart.
D)all of the above answers are correct.

Question 28

The relationship between oxygen uptake,cardiac output,and the arterial-venous oxygen difference is described mathematically by the

A)Hill equation.
B)Fenn equation.
C)Fick equation.
D)Frank-Starling law.

Question 29

At any level of oxygen consumption,heart rate and blood pressure are lower during leg work when compared with arm work.

Question 30

Which of the following factors has the greatest influence on blood flow to a skeletal muscle during exercise?

A)arterial pressure
B)diameter of the arterial blood vessels leading to the muscle
C)number of capillaries surrounding the muscle
D)the viscosity of the blood

Question 31

Autoregulation of blood flow to contracting muscles during exercise is due to

A)the withdrawal of sympathetic impulses to arteries.
B)an increase in parasympathetic outflow to arterioles.
C)locally produced factors such as nitric oxide,prostaglandins,and adenosine.
D)an increase in sympathetic impulses to arterioles.

Question 32

One reason the stroke volume increases during exercise is that skeletal muscle vasodilation decreases afterload.

Question 33

The greatest resistance to blood flow is in the

A)veins.
B)arterioles.
C)aorta.
D)capillaries.

Question 34

The metabolic demand of the heart can be estimated by

A)the rate-pressure product.
B)the double product.
C)multiplying heart rate by systolic blood pressure.
D)all of the above.

Question 35

Sympatholysis refers to

A)local inhibition of the parasympathetic nervous system.
B)local inhibition of sympathetic-induced vasoconstriction.
C)increased sympathetic nervous system activity during exercise.
D)none of the above answers are correct

Question 36

Which of the following statements about heart rate variability (HRV)is NOT true?

A)HRV refers to the time interval between heart beats.
B)Epidemiological studies suggest that a low HRV is an excellent predictor of mortality in some patient populations.
C)HRV decreases in response to regular aerobic exercise training.
D)HRV is influenced by the balance between the parasympathetic nervous system and the sympathetic nervous system.

Question 37

Which of the following factors DO NOT contribute to "fine-tuning" of cardiovascular control during exercise?

A)muscle chemoreceptors
B)baroreceptors
C)muscle mechanoreceptors
D)blood vessels

Question 38

The central command theory of cardiovascular control proposes that initial signal to the cardiovascular control center comes from

A)the cerebellum.
B)the brainstem.
C)higher brain centers
D)feedback loops coming from muscle receptors.

Question 39

A local increase in the nitric oxide concentration around arterioles would result in

A)vasoconstriction.
B)no change in vessel diameter.
C)vasodilation.
D)none of the above answers are correct

Question 40

The arterial-venous oxygen difference

A)increases as a function of exercise intensity.
B)does not change during exercise.
C)decreases as the exercise intensity increases.
D)is highest during submaximal exercise.

Question 41

At any end-diastolic volume,stroke volume is increased by parasympathetic stimulation.

Question 42

At the onset of exercise,the initial drive to increase heart rate comes from higher brain centers.

Question 43

An increase in cardiac output during exercise will decrease arterial blood pressure when peripheral resistance remains constant.

Question 44

Exercise training helps the heart resist damage during a heart attack.