Deck 18: Regulation of the Heart and Vasculature

Question 1

During a cardiovascular examination,a patient has a resting heart rate of 65 beats/minute and a blood pressure of 100/70 mm Hg in the supine position.In the upright position at steady state,the patient's heart rate is 74 beats/minute,and the blood pressure is 105/70 mm Hg.One physiological change that occurred in the patient as a result of assuming an upright position is:

A)Diminished arteriolar resistance.
B)Increased venous capacitance.
C)Increased capillary filtration.
D)Increased cardiac vagal tone.
E)Increased cardiac sympathetic tone.

Answer 1

E

Question 2

During a cardiovascular examination,a patient has a resting heart rate of 65 beats/minute and a blood pressure of 100/70 mm Hg in the supine position.In the upright position at steady state,the patient's heart rate is 74 beats/minute,and the blood pressure is 105/70 mm Hg. Agents that increase intracellular cyclic adenosine monophosphate (cAMP),such as β-adrenergic agonists,have a potent vasodilator effect by:

A)Increasing nitric oxide production in smooth muscle.
B)Stimulating guanylate cyclase activity in endothelial cells.
C)Reducing myosin light-chain kinase (MLCK)activity.
D)Suppressing calcium entry into smooth muscle cells.
E)Reducing the synthesis of guanosine monophosphate (cGMP)in smooth muscle

Answer 2

C

Question 3

The myogenic mechanism for autoregulation of vascular smooth muscle tone:

A)Requires the release of nitric oxide from endothelial cells.
B)Involves the release of norepinephrine from sympathetic nerve endings.
C)Responds to changes in vessel wall transmural pressure.
D)Depends on changes in flow through the vessel.
E)Arises from changes in shear stress in the vessel wall.

Answer 3

C

Question 4

A 24-year-old man is seen for a routine physical examination.At rest,his blood pressure is 120/80 mm Hg and his heart rate is 75 beats/minute.He is advised to begin an exercise program.When he returns 3 months later,his heart rate has decreased to 50 beats/minute (asymptomatic).Which of the set of values below would you expect to observe in this patient at rest in comparison with those 3 months ago?