Because many of the same cardiac cells are innervated by both parasympathetic and sympathetic fibers, the influence of the two divisions on the heart is synergistic, meaning contraction is strongest when both divisions act together.

Question

Quizplus · Accepted Answer

The influence of the parasympathetic and sympathetic divisions on the heart is antagonistic, not synergistic. The sympathetic division increases heart rate and contractility, while the parasympathetic division decreases heart rate. They work in opposition to maintain heart function balance.

Because Many of the Same Cardiac Cells Are Innervated by Both