Which of the following is not a mechanism that facilitates return of venous blood to the heart?
A) Gravity, when veins are above the heart
B) Contraction of skeletal muscles
C) Breathing
D) Contraction of smooth muscle in most veins of the body
E) Valves in veins

Question

Quizplus · Accepted Answer

Contraction of smooth muscle in most veins of the body does not facilitate the return of venous blood to the heart. In fact, smooth muscle contraction can impede blood flow in veins. The other mechanisms listed (gravity, contraction of skeletal muscles, breathing, and valves in veins) all contribute to venous return.

Which of the Following Is Not a Mechanism That Facilitates