Which mechanism is not one of the mechanisms that facilitates the 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 is not one of the mechanisms that facilitates the return of venous blood to the heart. Veins have valves that prevent the backflow of blood, and the other mechanisms include gravity when veins are above the heart, contraction of skeletal muscles, and breathing.

Which Mechanism Is Not One of the Mechanisms That Facilitates