Why would stroke volume increase during exercise?
I.Parasympathetic discharge increases cardiac contractility
II.Vasodilation of working muscles increases venous return to the heart
III.Vascoconstriction of peripheral venous blood reservoirs increases venous return
A) II and III only
B) I , II, and III
C) I only
D) I and III only

Question

Quizplus · Accepted Answer

During exercise, working muscles require more oxygen and nutrients and therefore vasodilation occurs, which increases blood flow to the muscles. This increased blood flow leads to an increase in venous return to the heart, which increases stroke volume. Vasodilation occurs as a result of local metabolic factors, not parasympathetic discharge which decreases cardiac contractility. Vasconstriction of peripheral venous blood reservoirs would actually decrease venous return, not increase it, so III is incorrect. Therefore, II and III are the correct choices.

Why Would Stroke Volume Increase During Exercise