Section III: Cardiovascular Physiology

Question 1

Chapter 18

What is the name of the condition when blood flow to a tissue is inadequate to meet the metabolic needs of the tissue?

a. Anemia
b. Edema
c. Necrosis
d. Ischemia
e. Infarction

Answer 1

D

Question 2

The volume of blood pumped by the left ventricle in 1 minute would equal:

a. The volume of blood that flowed through the coronary circulation (in the same minute).
b. The volume of blood that flowed through all organs of the systemic circulation, except for coronary blood flow.
c. The volume of blood that flowed through the lungs.
d. One-half of the cardiac output.
e. Two times the cardiac output.

Answer 2

C

Question 3

A transfusion of normal plasma into a normal dog would:

a. Decrease the hematocrit of the recipient’s blood.
b. Increase the viscosity of the recipient’s blood.
c. Decrease the mean corpuscular hemoglobin concentration (MCHC) in the recipient’s plasma.
d. Increase the number of cells in the recipient’s blood.
e. Decrease the concentration of proteins in the recipient’s plasma.

Answer 3

A

Question 4

Which of the following sequences of capillary beds might a red blood cell encounter in a normal circulation?

a. Lungs, skin, lungs, brain
b. Spleen, liver, mesentery, lungs
c. Coronary, kidney (glomerular), kidney (tubular), lungs
d. Lungs, coronary, stomach, liver
e. Brain, lungs, liver, coronary

Answer 4

A

Question 5

The walls of most capillaries have pores or clefts in them, which are approximately 4 nm (4 × 10–9 m) in diameter.

a. A capillary pore is many times larger in diameter than a sodium ion.
b. A capillary pore is many times larger in diameter than a glucose molecule.
c. The diameter of a red blood cell is many times greater than the diameter of a capillary pore.
d. A molecule of β globulin or γ globulin could just about squeeze through a capillary pore if it were lined up exactly
right.
e. All of the above are correct.

Answer 5

E

Question 6

Suppose that the following conditions exist in a particular blood vessel: blood pressure (BP) inside vessel at inlet = 60 mm Hg, BP inside vessel at midpoint = 50 mm Hg, and BP inside vessel at outlet = 40 mm Hg. Pressure in the tissue fluid (interstitial fluid) immediately outside vessel = 5 mm Hg. Under these
conditions:

a. Perfusion pressure for blood flow through this vessel =20 mm Hg.
b. Perfusion pressure for blood flow through this vessel =15 mm Hg.
c. Distending pressure at the vessel midpoint = 55 mm Hg.
d. Distending pressure at the vessel midpoint = 45 mm Hg.
e. Both a and d are correct

Answer 6

E

Question 7

Compared with the systemic circulation, the pulmonary circulation:

a. Carries more blood flow per minute.
b. Has a lower perfusion pressure.
c. Has a higher resistance to blood flow.
d. Carries blood that has a lower hematocrit.
e. Contains a higher blood volume.

Answer 7

B

Question 8

Chapter 19 Electrical Activity of the Heart

Which of the following is true for both cardiac muscle and skeletal muscle?

a. The muscle forms a functional syncytium.
b. An action potential in the muscle cell membrane is required to initiate contraction.
c. Pacemaker cells spontaneously depolarize to threshold and initiate action potentials.
d. Frequent action potentials in motor neurons can cause a sustained (tetanic) muscle contraction.
e. Extracellular Ca2+ enters the muscle cell during an action potential and triggers the release of additional Ca2+ from the sarcoplasmic reticulum.

Answer 8

B

Question 9

The normal pathway followed by a cardiac action potential is to begin in the SA node and then propagate:

a. Across the atria in the bundle of His.
b. Through the connective tissue layers that separate the atria and ventricles.
c. Across the atria and into the AV node.
d. From the left atrium to the right atrium.
e. From the left atrium to the left ventricle and from the right atrium to the right ventricle

Answer 9

C

Question 10

At the moment when an action potential begins propagating slowly through the AV node in a normal resting dog, the
ventricular muscle cells are:

a. At their resting membrane potential.
b. Depolarizing slowly toward threshold for formation of an action potential.
c. Undergoing rapid depolarization at the beginning of an action potential.
d. At the plateau of an action potential.
e. Just ending their action potential (i.e., repolarizing back toward resting membrane potential).

Answer 10

A

Question 11

During which phase of a normal ventricular action potential is it most likely that fast Na+channels are in an inactivated state, slow Ca2+ channels are open, and most K+ channels are closed?

a. Phase 0 (rapid depolarization)
b. Phase 1 (partial repolarization)
c. Phase 2 (plateau)
d. Phase 3 (repolarization)
e. Phase 4 (rest)

Answer 11

C

Question 12

An increase in heart rate could result from:

a. An increase in sympathetic nerve activity to the heart.
b. A decrease in parasympathetic nerve activity to the heart.
c. An abnormally rapid decrease in permeability of SA node cells to K+ during diastole.
d. An abnormally rapid increase in permeability of SA node cells to Na+ during diastole.
e. All the above are correct

Answer 12

E

Question 13

In which of the following arrhythmias will there be more atrial beats per minute than ventricular beats?

a. Complete (third-degree) AV block
b. Frequent premature ventricular contractions
c. Sick sinus syndrome (sinus bradycardia)
d. First-degree AV block
e. Ventricular tachycardia

Answer 13

A

Question 14

Which of the following types of drugs would be the best choice to treat a patient with both supraventricular tachycardia and inadequate cardiac contractility?

a. Local anesthetic (fast Na+channel blocker)
b. Muscarinic cholinergic antagonist
c. Beta-adrenergic agonist
d. Cardiac glycoside (inhibits Na+, K+
pump)
e. Calcium channel blocker

Answer 14

D

Question 15

Chapter 20 The Electrocardiogram

Which of the following intervals on an ECG most closely corresponds to the time required for propagation of a cardiac
action potential through the AV node?

a. RR interval
b. PR interval
c. ST interval
d. PP interval
e. QT interval

Answer 15

B

Question 16

The T wave in a normal lead I ECG is:

a. Always negative.
b. Always positive if the R wave is positive.
c. Also known as the pacemaker potential.
d. Caused by the delay between atrial and ventricular depolarization.
e. Caused by ventricular repolarization.

Answer 16

E

Question 17

What would the lead I ECG look like if an ectopic pacemaker in the free wall of the left atrium subsumed the role of the SA
node (i.e., “took over” the initiation of atrial action potentials)?

a. The ECG would appear normal.
b. The order of waves would be reversed (i.e. T-QRS-P, instead of P-QRS-T)
c. The P waves and T waves would appear normal, but there would be no R waves.
d. The P wave would be negative and the R wave would be positive.
e. The P wave would be negative and the R wave would be negative.

Answer 17

D

Question 18

In which of the following arrhythmias will the ECG characteristically show the same number of P waves and QRS complexes?

a. Complete (third-degree) AV block
b. First-degree AV block
c. Ventricular tachycardia
d. Atrial flutter
e. All the above are correct.

Answer 18

B

Question 19

Chapter 21 The Heart As a Pump

During a normal cardiac cycle, which of the following events happens soonest after the first heart sound is heard?

a. Atrial contraction begins.
b. The mitral valve opens.
c. Atrial depolarization begins.
d. Ventricular ejection begins.
e. The aortic valve closes

Answer 19

D

Question 20

In the normal cardiac cycle:

a. The P wave in the electrocardiogram coincides with the beginning of ventricular ejection.
b. The second heart sound coincides with the beginning of isovolumetric relaxation.
c. Left ventricular pressure reaches its highest level just as the aortic valve closes.
d. Aortic pressure reaches its highest level at the beginning of ventricular systole.
e. The mitral valve is open throughout ventricular diastole.

Answer 20

B

Question 21

An abnormality that causes a sustained decrease in left ventricular compliance is most likely to result in an increased:

a. Left ventricular stroke volume
b. Left atrial volume and pressure
c. Left ventricular afterload
d. Pulmonary blood flow
e. Left ventricular end-diastolic volume

Answer 21

B

Question 22

Which of the following cause-and-effect statements is true for a normal heart?

a. Sympathetic activation causes end-systolic ventricular volume to increase.
b. An increase in ventricular preload causes end-diastolic ventricular volume to decrease.
c. Pacing the heart at a high rate causes stroke volume to decrease.
d. An increase in ventricular contractility causes systolic duration to increase.
e. An increase in ventricular contractility causes the external work of the heart to decrease

Answer 22

C

Question 23

Chapter 22 The Systemic and Pulmonary Circulations

The magnitude of pulsations in blood pressure (caused by the pulsatile ejection of blood from the heart) is greatest in the:

a. Arteries
b. Arterioles
c. Capillaries
d. Veins
e. Venae cavae

Answer 23

A

Question 24

Which of the following is a correct comparison between segments of the systemic circulation?

a. The aorta and large arteries have a higher resistance to blood flow than the capillaries.
b. The arterioles have a higher resistance to blood flow than the capillaries.
c. The veins have a higher resistance to blood flow than the capillaries.
d. The aorta and large arteries have a higher compliance than the veins.
e. The aorta and large arteries contain a greater volume of blood than the veins and venae cavae

Answer 24

B

Question 25

If the heart suddenly stops beating in an otherwise normal dog, which of the following would be most likely to increase?

a. Mean circulatory filling pressure
b. Mean aortic pressure
c. Vena caval pressure
d. Perfusion pressure for the systemic circulation
e. Perfusion pressure for the pulmonary circulation

Answer 25

C

Question 26

Which of the following would cause mean aortic pressure to increase?

a. Stroke volume increases from 30 to 40 mL, and heart rate decreases from 100 to 60 beats/min.
b. Arterial compliance decreases.
c. Cardiac output decreases.
d. Arterioles throughout the body dilate.
e. TPR increases

Answer 26

E

Question 27

If aortic compliance decreases while heart rate, cardiac output, and total peripheral resistance (TPR) remain unchanged:

a. Pulse pressure will be unchanged.
b. Pulse pressure will increase.
c. Pulse pressure will decrease.
d. One cannot know the effect on pulse pressure because stroke volume may have changed.
e. One cannot know the effect on pulse pressure because mean aortic pressure may have changed

Answer 27

B

Question 28

The following measurements are made on a dog exhibiting distress following surgery: heart rate, 80 beats/min; stroke volume, 30 mL; mean aortic pressure, 96 mm Hg; mean pulmonary artery pressure, 26 mm Hg; left atrial pressure, 5 mm Hg; and right atrial pressure, 12 mm Hg. Which of the
following is the best estimate for the TPR of this dog?

a. 8.75 mm Hg/L/min
b. 10.83 mm Hg/L/min
c. 29.17 mm Hg/L/min
d. 35.00 mm Hg/L/min
e. 40.00 mm Hg/L/min

Answer 28

D

Question 29

For the dog described in Question 6, the perfusion pressure for the systemic circulation is approximately _ the perfusion pressure for the pulmonary circulation.

a. Half as much as
b. Equal to
c. Twice as high as
d. Four times higher than
e. Nine times higher than

Answer 29

D

Question 30

The blood flow through the brain of a resting dog would be decreased most by a 20% decrease in the:

a. Mean arterial pressure
b. Heart rate
c. Systemic perfusion pressure
d. Radius of arteries in the brain
e. Radius of arterioles in the brain

Answer 30

E

Question 31

Chapter 23 Capillaries and Fluid Exchange

The rate of diffusion of glucose molecules from capillary blood to interstitial fluid is most directly affected by the:

a. Capillary plasma oncotic pressure.
b. Interstitial fluid hydrostatic pressure.
c. Size and number of capillary pores.
d. Amount of oxygen in the blood.
e. Hematocrit.

Answer 31

C

Question 32

For continuous capillaries, such as those found in skeletal muscle, the capillary surface area available for diffusion is greatest for which of the following?

a. Glucose
b. Dissolved oxygen
c. Ions, such as Na+, K+, and Cl−
d. Amino acids
e. Plasma proteins

Answer 32

B

Question 33

An increase in the venous resistance (e.g., too tight a bandage on an extremity) causes edema because:

a. Lymph flow increases.
b. Pinocytosis cannot remove excess interstitial fluid fast enough.
c. Capillary hydrostatic pressure increases.
d. The interstitial proteins block up lymph channels.
e. The interstitial fluid pressure decrease

Answer 33

C

Question 34

Which of the following will NOT cause pulmonary edema?

a. An increase in pulmonary capillary permeability to protein
b. A blockage of pulmonary lymph vessels
c. An increase in left atrial pressure
d. A constriction of pulmonary arterioles
e. Left-sided heart failure

Answer 34

D

Question 35

A patient with a form of protein-losing kidney disease has a plasma colloid osmotic pressure of 10 mm Hg. The patient has edema but is not getting any worse. Blood pressure and heart
rate are normal. Which of the following is probably preventing further edema?

a. Increased capillary hydrostatic pressure
b. Decreased lymph flow
c. Decreased concentration of plasma proteins in the plasma
d. Increased interstitial fluid oncotic pressure
e. Increased interstitial fluid hydrostatic pressure

Answer 35

E

Question 36

The following parameters exist in the microcirculation of a skeletal muscle during a period of vigorous exercise:
Pc (capillary hydrostatic pressure) = 34 mm Hg
Pi (interstitial fluid hydrostatic pressure) = 10 mm Hg
πc (capillary plasma oncotic pressure) = 24 mm Hg
πi (interstitial fluid oncotic pressure) = 3 mm Hg
Which of the following is true?

a. These conditions favor filtration.
b. These conditions favor reabsorption.
c. These conditions favor neither filtration nor reabsorption.
d. It is not clear what these conditions favor because the concentration of plasma protein is not specified.
e. It is not clear what these conditions favor because the rate of lymph flow is not specified.

Answer 36

A

Question 37

Histamine and bradykinin cause edema by increasing BOTH:

a. Capillary permeability to plasma protein AND interstitial hydrostatic pressure.
b. Interstitial colloid osmotic pressure AND lymph flow.
c. Capillary hydrostatic pressure AND capillary permeability to plasma protein.
d. Capillary hydrostatic pressure AND plasma colloid osmotic pressure.
e. Lymph flow AND interstitial hydrostatic pressure

Answer 37

A

Question 38

During a 30-minute hemorrhage, a horse loses a substantial volume of blood. The horse’s mean arterial pressure decreases
from 90 to 75 mm Hg, and the heart rate increases from 40 to 90 beats/min. The skin becomes cool and the mucous
membranes become pale, suggesting marked vasoconstriction. Because hemorrhage involves the loss of whole blood (both plasma and cells), you might expect that, soon after such a hemorrhage, the horse’s remaining blood would still have a normal composition. However, you take a blood sample and
discover that the hematocrit is abnormally low (only 28%). Which of the following would most likely account for the decrease in hematocrit observed after the hemorrhage?

a. Excessive capillary filtration has caused interstitial fluid
pressure to increase above normal.
b. Excessive capillary filtration has caused capillary colloid osmotic pressure to increase above normal.
c. Arteriolar constriction has caused capillary hydrostatic pressure to increase above normal.
d. Low capillary hydrostatic pressure has caused interstitial fluid to be reabsorbed into the bloodstream.
e. Many blood cells have been filtered out of capillaries and into the interstitial fluid

Answer 38

D

Question 39

Chapter 24 Local Control of Blood Flow

Intrinsic control of blood flow is most likely to predominate over extrinsic control of blood flow in:

a. The splanchnic circulation
b. The kidneys
c. Resting skeletal muscle
d. Exercising skeletal muscle
e. Skin

Answer 39

D

Question 40

The increase in coronary blood flow during exercise is:

a. Called Starling’s law of the heart.
b. Called reactive hyperemia.
c. Caused by activation of parasympathetic nerves to the heart.
d. Caused by compression of the coronary blood vessels during systole.
e. Closely matched to the increased metabolic requirements of the heart muscle

Answer 40

E

Question 41

he metabolic control mechanism serves to match blood flow in a tissue to the tissue’s metabolic activity. Which of the following variables is actually being regulated (i.e., held constant) by the metabolic control mechanism?

a. Perfusion pressure applied to the tissue.
b. Blood flow to the tissue.
c. Arteriolar resistance in the tissue.
d. Oxygen concentration in the tissue interstitial fluid.
e. The number of open capillaries (i.e., the number of capillaries carrying blood flow at any one time)

Answer 41

D

Question 42

A dog with an arterial blood pressure of 120/80 mm Hg has a cerebral blood flow of 100 mL/min. When blood pressure is
increased to 130/100 mm Hg, the cerebral blood flow increases to 105 mL/min. This is an example of:

a. Active hyperemia
b. Autoregulation
c. Reactive hyperemia
d. The blood-brain barrier
e. Hypoxic vasoconstriction

Answer 42

B

Question 43

In response to an increase in perfusion pressure, the arterioles
of an autoregulating organ _ , and the vascular resistance of the organ _ .

a. constrict; increases
b. constrict; decreases
c. dilate; increases
d. dilate; decreases

Answer 43

A

Question 44

Which of the following characteristically acts as a paracrine to cause vasoconstriction in systemic arterioles?

a. Carbon dioxide
b. Nitric oxide
c. Endothelin-1 (ET1)
d. Prostacyclin (PGI2)
e. Bradykinin

Answer 44

C

Question 45

Blood flow to skeletal muscle increases dramatically during dynamic exercise (e.g., running or swimming, during which
the exercising muscles alternate between contraction and relaxation). The increase in muscle blood flow is much smaller
during static exercise (e.g., pushing hard against an immovable object, during which the exercising muscles maintain a forceful,
steady contraction). The limited increase in muscle blood flow during static exercise is best explained by:

a. Mechanical compression of muscle blood vessels.
b. Metabolic control of muscle blood flow, leading to arteriolar vasodilation.
c. Metabolic control of muscle blood flow, leading to arteriolar vasoconstriction.
d. Autoregulation of blood flow, leading to arteriolar vasoconstriction.
e. The release of histamine and bradykinin by the contracting muscle cells

Answer 45

A

Question 46

When a young dog with a PDA attempts vigorous exercise:
a. Arterioles in the exercising skeletal muscle constrict.
b. Oxygen concentration in the skeletal muscle interstitial fluid decreases.
c. Left ventricular output decreases.
d. Right ventricular output decreases.
e. Mean arterial pressure increases to very high levels

Answer 46

B

Question 47

Chapter 25 Neural and Hormonal Control of Blood Pressure and Blood Volum

Neural-hormonal control of blood flow is most directly responsible for which of the following responses in a skeletal muscle?

a. Active hyperemia
b. Reactive hyperemia
c. Autoregulation
d. Decreased blood flow during a period of mechanical compression
e. Increased blood flow in anticipation of exercise

Answer 47

E

Question 48

The normal reflex responses to a sudden increase in arterial blood pressure include an increase in:

a. Heart rate.
b. Renin release from the kidney.
c. Parasympathetic activity directed to the heart.
d. Sympathetic activity directed to blood vessels in kidneys, resting skeletal muscles, and splanchnic organs.
e. Sympathetic activity directed to blood vessels in brain, coronary circulation, and exercising skeletal muscles.

Answer 48

C

Question 49

Vasovagal syncope:

a. Involves decreased blood pressure and heart rate.
b. Involves increased sympathetic activity.
c. Involves decreased cardiac parasympathetic activity.
d. Involves constriction of splanchnic arterioles.
e. Prepares an animal for “fight or flight.

Answer 49

A

Question 50

Which of the following would prevent the dilation of arterioles in an exercising muscle?

a. Surgically cutting all the autonomic nerves that innervate the muscle.
b. Administering a drug that stimulates the release of epinephrine and norepinephrine from the adrenal glands.
c. Administering a drug that blocks muscarinic cholinergic receptors.
d. Administering a drug that blocks β-adrenergic receptors.
e. None of the above is correct.

Answer 50

E

Question 51

A drug is injected intravenously into a dog and causes a transient increase in mean arterial pressure and a transient decrease in heart rate. The baroreceptor nerves are then cut and the drug is reinjected. This time, the drug causes a larger increase in
blood pressure but no change in heart rate. These results are most consistent with the primary action of the drug being to:

a. Activate the muscarinic cholinergic (M3) receptors of arterioles.
b. Activate the α-adrenergic receptors of arterioles.
c. Activate β1-adrenergic receptors of the pacemaker cells of the SA node.
d. Increase the synthesis of nitric oxide in arterioles.
e. Decrease the activity of arterial baroreceptors.

Answer 51

B

Question 52

A dog has suffered a substantial hemorrhage. The dog’s heart
rate is increased above normal, and the skin is cold. The mucous membranes are pale, and capillary refill time is prolonged. In this situation (compared with normal):

a. The baroreceptor nerves are firing at an increased rate.
b. The sympathetic nerves to the heart are firing at a decreased rate.
c. The sympathetic nerves to the blood vessels of the skin and mucous membranes are firing at an increased rate.
d. The parasympathetic nerves to the blood vessels are firing at an increased rate.
e. The release of renin by the kidney is decreased.

Answer 52

C

Question 53

During a defense-alarm reaction (fight-or-flight response), heart rate increases because of:

a. Increased circulating acetylcholine released from the adrenal glands.
b. Increased activation of the arterial baroreceptors.
c. Increased arterial blood pressure.
d. Increased sympathetic nerve activity.
e. Increased parasympathetic activity.

Answer 53

D

Question 54

Chapter 26 Integrated Cardiovascular Responses

What goes in the blank in the following sequence of cause and effect?
Myocardial failure → Decreased cardiac contractility → _ → Decreased stroke volume.

a. Increased end-diastolic volume
b. Decreased end-diastolic volume
c. Increased end-systolic volume
d. Decreased heart rate
e. Increased mean aortic pressure

Answer 54

C

Question 55

Which of the following is most likely to be the cause of dependent edema (swelling in regions of the body below the
level of the heart) in a dog with chronic heart failure secondary to hypertrophic cardiomyopathy?

a. Increased lymph flow
b. Increased capillary hydrostatic pressure
c. Increased interstitial fluid hydrostatic pressure
d. Increased plasma colloid osmotic (oncotic) pressure
e. Increased interstitial fluid colloid osmotic (oncotic) pressure

Answer 55

B

Question 56

During experimental trials on a new artificial aortic valve, a 20-kg dog is anesthetized and placed on cardiac bypass for 1 hour (i.e., a heart-lung machine is substituted for the dog’s
own heart and lungs). After successful installation of the artificial valve, the dog is taken off bypass, and the normal
circulation is restored. One hour later, the dog’s central venous pressure is 20 mm Hg, mean arterial pressure is 75 mm Hg,
and heart rate is 140 beats/min. The cardiac output is not measured, but the surgeon suspects that it is too low, and
therefore the dog’s tissues are not being adequately supplied with blood. Which of the following procedures would be
most likely to improve the delivery of blood to the dog’s tissues?

a. Administration of a drug that increases cardiac contractility (e.g., digitalis)
b. Administration of an α-adrenergic agonist drug (e.g., phentolamine)
c. Administration of a β-adrenergic antagonist drug (e.g., propranolol)
d. Increasing the heart rate by electrical pacing
e. Transfusion with 500 mL of whole blood

Answer 56

A

Question 57

What goes in the blank in the following sequence of cause and effect?
Hemorrhage → Decreased central venous pressure → Decreased ventricular preload → _ → Decreased stroke volume.

a. Decreased ventricular contractility
b. Decreased systolic duration
c. Decreased arterial baroreceptor activity
d. Decreased diastolic filling time
e. Decreased end-diastolic volume

Answer 57

E

Question 58

Which of the following is most likely to be below normal in a dog that is beginning to compensate for a significant hemorrhage?

a. Activity of the arterial baroreceptors
b. Release of ADH from the pituitary gland
c. Sensation of thirst
d. Sympathetic nerve activity to the systemic arterioles
e. Sympathetic nerve activity to the heart

Answer 58

A

Question 59

A dog suffers a sudden, severe hemorrhage. One hour later, the dog is resting quietly, but his arterial pulse pressure, mean pressure, and hematocrit are all below normal. His mucous
membranes are pale, and capillary refill time is longer than normal. Which of the following is most likely?

a. The diminished pulse pressure results from an abnormally low heart rate.
b. The diminished mean pressure results from an abnormally low total peripheral resistance.
c. The diminished hematocrit results from reabsorption of interstitial fluid into the bloodstream.
d. The pale mucous membranes result from abnormally low plasma protein concentration
e. The prolonged capillary refill time results from decreased sympathetic nerve activity to the blood vessels.

Answer 59

C

Question 60

When a sheep is held in a vertical, head-up position, cardiac output decreases because:

a. Sympathetic nerve activity causes the spleen to contract and abdominal veins to constrict.
b. Valves in the leg veins prevent the return of blood to the heart.
c. The respiratory pump promotes movement of abdominal venous blood into the thorax.
d. Central blood volume increases.
e. Right atrial pressure decreases.

Answer 60

E

Question 61

What goes in the blank in the following sequence of cause and effect?
Initiation of skeletal muscle exercise → Increased metabolic rate in exercising muscles → _ → Increased blood flow in exercising muscles.

a. Decreased cardiac output
b. Decreased arterial pressure
c. Vasodilation in exercising muscle
d. Increased total peripheral resistance
e. Increased delivery of oxygen to exercising muscle

Answer 61

C

Question 62

During the transition from rest to exercise in a normal dog, which of the following will decrease?

a. The external work (pumping work) of the heart
b. The heart muscle’s total work (total energy consumption)
c. Blood flow through the lungs
d. Systolic duration
e. Velocity with which action potentials are conducted through the AV node

Answer 62

D

Question 63

When a horse is running, the deep breathing and rhythmic contraction/relaxation of skeletal muscles help to maintain an elevated cardiac output by increasing:

a. Venous return and central venous pressure
b. Venous distending pressure in the legs
c. Cardiac contractility
d. Total peripheral resistance
e. Intrathoracic (intrapleural) pressure

Answer 63

A

Question 64

The responses to myocardial failure, hemorrhage, and exercise have in common that ________________ will be elevated above its normal, resting level.

a. Total peripheral resistance
b. Heart rate
c. Cardiac contractility
d. Stroke volume
e. Central venous pressure

Answer 64

B