Question

Q.The medullary cardiovascular center in the medulla:

a. is activated by epinephrine and inhibited by acetylcholine

. b. is activated by the heart.

c. activates the sympathetic nervous system and inhibits the parasympathetic nervous system.

d. releases both epinephrine and acetylcholine.

e. incrpPeases the heart rate by stimulating the parasympathetic nervous system.

Q.How do arteries contribute to an increase in systemic blood pressure?

a. Vasoconstriction of peripheral arteries reduces systemic arterial volume.

b. Vasodilation of peripheral arteries increases systemic arterial volume.

c. Arteries release renin-angiotensin to increase blood flow.

d. Peripheral arteries close down valves to slow down blood flow.

e. Arteries dilate and contract in synchrony with the cardiac rhythm.

Q. Which of the following statement regarding the cardiac cycle is correct?

a. During diastole, the atria dilate, the ventricles contract.

b. The sympathetic nervous system shortens the cardiac cycle by reducing the duration of muscle action potentials.

c. In a normal heart, the pace of the cardiac cycle is set by the atrioventricular node.

d. Beating of the left and the right sides of the heart is 180° out of phase.

e. In each cycle, the amount of blood leaving and returning to the heart is the same.

Answer 1

1. c. activates the sympathetic nervous system and inhibits the parasympathetic nervous system.

Explanation: Medullary cardiovascular system stimulates the sympathetic system to increase the heart rate and heart contractility.

2. a. Vasoconstriction of peripheral arteries reduces systemic arterial volume.

Explanation: Systemic blood pressure is increased when vasoconstriction of the arteries occur causing resistance to the blood flow.

3. b. The sympathetic nervous system shortens the cardiac cycle by reducing the duration of muscle action potentials.

Explanation: The sympathetic nervous system shortens the cardiac cycle by reducing the duration of muscle action potentials, this increases the heart rate.