The parasympathetic fibers of the vagus nerve
A) speed up the heartbeat.
B) increase the force of cardiac contractions.
C) slow the heartbeat.
D) decrease the force of cardiac contractions.

Question

Quizplus · Accepted Answer

The parasympathetic fibers of the vagus nerve slow down the heartbeat by decreasing the rate of depolarization in the sinoatrial node, which sets the pace for the heart's contractions. These fibers also decrease the force of cardiac contractions. Therefore, choices A and B are incorrect, and choice D is only partially correct.

The Parasympathetic Fibers of the Vagus Nerve