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. Vasoconstriction of peripheral venous blood reservoirs increases venous return
A) I and III only
B) I only
C) II and III only
D) I , II, and III

Question

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. Vasoconstriction of peripheral venous blood reservoirs increases venous return
A) I and III only
B) I only
C) II and III only
D) I , II, and III

Quizplus · Accepted Answer

II and III are correct because during exercise, vasodilation in working muscles increases venous return to the heart, and vasoconstriction of peripheral venous reservoirs also increases venous return, both of which can lead to an increase in stroke volume. Parasympathetic activity typically decreases during exercise, while sympathetic activity increases, enhancing cardiac contractility and heart rate, not parasympathetic discharge.

Why Would Stroke Volume Increase During Exercise