Question

Which of the following factors greatly improves venous return to the heart during strenuous exercise?

a. Rapid emptying of the right side of the heart
b. Forceful action of the valves in the veins
c. Contraction and relaxation of skeletal muscles
d. Peristalsis in the large veins

Answer 1

The contraction and relaxation of skeletal muscles, also known as the skeletal muscle pump, is a factor that greatly improves venous return to the heart during strenuous exercise (Option C).

Step-by-step explanation:

One of the factors that greatly improves venous return to the heart during strenuous exercise is the contraction and relaxation of skeletal muscles. This mechanism, known as the skeletal muscle pump, increases the pressure in the veins as the surrounding skeletal muscles contract.

This pressure helps blood in the veins overcome gravity and return to the heart, supported by one-way valves that ensure blood flows in the proper direction. Particularly in the legs during activities like walking or running, this muscle pump is essential to prevent blood from pooling in the lower extremities, thereby maintaining efficient circulation.

Thus, the correct option is C.

Answer 2

The contraction and relaxation of skeletal muscles, known as the skeletal muscle pump, significantly improves venous return to the heart by increasing venous pressure and assisting one-way vein valves in preventing blood backflow.

The correct answer is options C

Step-by-step explanation:

The skeletal muscle pump is a mechanism by which the contraction and relaxation of skeletal muscles greatly improves venous return to the heart during strenuous exercise. This process helps to increase the pressure within veins, pushing the blood upwards against the force of gravity. Valves within the veins prevent backflow, ensuring that blood returns efficiently to the heart. Consequently, option c. Contraction and relaxation of skeletal muscles is the correct answer to the student's question regarding factors that improve venous return during exercise.