PRACTICE QUESTIONS

1. The increase in coronary blood flow during exercise is:

a. Called Starlings law of the heart.

b. Caused by sympathetic activation of α-adrenergic receptors.

c. Caused by compression of the coronary blood vessels during systole.

d. Closely matched to the metabolic requirements of the heart.

e. Called reactive hyperemia.

2. 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

3. Local, metabolic control of blood flow through skeletal muscle:

a. Characteristically dominates over neurohumoral control.

b. Characteristically is subservient to neurohumoral control.

c. Can either dominate or be subservient to neuro­humoral control, depending on whether the muscle is exercising or resting.

d. Depends primarily on changes in the resistance of the arteries of the muscle.

e. Involves the release of histamine from mast cells within the skeletal muscle.

4. 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

5. 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.