Acetylcholine slows the heart because it
A)opens potassium ion channels in SA node cells.
B)opens sodium-calcium ion channels in SA node cells.
C)causes the pacemaker potential to depolarize more quickly.
D)causes the pacemaker potential to depolarize more slowly.
E)opens potassium ion channels in SA node cells and causes the pacemaker potential to depolarize more slowly.

Question

Quizplus · Accepted Answer

Acetylcholine slows the heart by opening potassium ion channels in SA node cells, which increases potassium efflux, hyperpolarizing the cell. This action, combined with a decrease in the rate of depolarization of the pacemaker potential, leads to a slower heart rate.

Acetylcholine Slows the Heart Because It