chapter9

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

40% of VO2max

Which of the following represents the correct order of events of the flow of blood after it leaves the left ventricle and before it returns to the right atrium?

Blood flows through the aorta, oxygen moves out of the capillaries, blood flows through the venules, blood enters the veins

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

FALSE

At any end-diastolic volume, stroke volume is increased by parasympathetic stimulation. TRUE OR FALSE?

FALSE

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

Fick equation

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

Frank-Starling law of the heart

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

HR max = 220 - age.

Which of the following statements about heart rate variability (HRV) is NOT true? -HRV refers to the time interval between heart beats. -Epidemiological studies suggest that a low HRV is an excellent predictor of mortality in some patient populations. -HRV decreases in response to regular aerobic exercise training. -HRV is influenced by the balance between the parasympathetic nervous system and the sympathetic nervous system.

HRV decreases in response to regular aerobic exercise training.

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

T wave

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

TRUE

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

TRUE

Exercise training helps the heart resist damage during a heart attack. TRUE OR FALSE?

TRUE

In general, heart rate increases in direct proportion to the metabolic rate during exercise. TRUE OR FALSE?

TRUE

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

TRUE

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. TRUE OR FALSE?

TRUE

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

The bundle branches depolarize, the ventricle contracts, the ventricular pressure increases, and blood exits the ventricle

An increase in parasympathetic outflow to the heart results in

a decrease in HR

The metabolic demand of the heart can be estimated by -multiplying heart rate by systolic blood pressure. -the rate-pressure product. -the double product. -all of these

all of these

Which of the following statement about beta-adrenergic blocking medications are true? -beta blocking drugs compete with epinephrine and norepinephrine for beta-adrenergic receptors in the heart -all of these answers are correct -beta blocking drugs reduce heart rate during exercise -beta blockade reduces the vigor of ventricular contraction

all of these answers are correct

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

an increase in cardiac output and a redistribution of blood flow from inactive tissues to skeletal muscles

Which of the following is NOT a mechanism for increasing venous return during exercise?

an increase in stroke volume

The greatest resistance to blood flow is in the

arterioles

Which of the following factors DO NOT contribute to "fine-tuning" of cardiovascular control during exercise? -muscle mechanoreceptors -blood vessels -baroreceptors -muscle chemoreceptors

blood vessels

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

both an increase in mean arterial pressure and a decrease in vascular resistance

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

both muscles are composed of striated fibers containing actin and myosin

All gas exchange between the vascular system and tissues occurs in

capillaries

The primary purpose of the cardiovascular system is to

deliver adequate levels of oxygen and remove wastes from body tissues

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

diameter of the arterial blood vessels leading to the muscle

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

higher brain centers

The arterial-venous oxygen difference

increase as a function of exercise intensity

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

increase by 100%

Electrical impulses are conducted between heart muscle cells by

intercalated discs

During exercise, the time spent in diastole and systole

is decreased, with the greatest decrease occurring in diastole

The relationship between cardiac output and metabolic rate is

linear

Sympatholysis refers to

local inhibition of sympathetic-induced vasoconstriction.

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

locally produced factors such as nitric oxide, prostaglandins, and adenosine

The cardiovascular control center is located in the

medulla oblongata

The muscle of the heart is referred to as the

myocardium

The difference between systolic and diastolic blood pressure is called the

pulse pressure

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

semilunar valves

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

shorter than diastole

The normal pacemaker of the heart is the

sinoatrial node

Which of the following factors can decrease blood pressure?

systemic vasodilation

The contraction phase of the heart is called

systole

The most important variable that determines resistance to blood flow is

the diameter of the vessel

Which of the following is true of the heart rate change during exercise?

the increase in HR is due to both a PNS withdrawal followed by increasing SNS influence

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

the increase in systolic blood pressure

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

vasodilation