Which of the following is the purpose of valves in the venous circulatory system?

A. Promoting movement of oxygenated blood toward the heart

B. Facilitating stasis of blood in the veins

C. Propelling blood through the vena cava

D. Preventing backward flow of deoxygenated blood

I think it's D

Agree

To determine the purpose of valves in the venous circulatory system, let's break down each option:

A. Promoting movement of oxygenated blood toward the heart: This is not the purpose of valves in the venous circulatory system. Valves are located specifically in veins, which carry deoxygenated blood towards the heart.

B. Facilitating stasis of blood in the veins: This is also not the purpose of valves in the venous circulatory system. Stasis refers to a lack of movement, whereas veins need to carry blood towards the heart.

C. Propelling blood through the vena cava: The vena cava is a large vein that brings blood from the body back to the heart. While valves do play a role in directing blood flow, they are not specifically involved in propelling blood through the vena cava.

D. Preventing backward flow of deoxygenated blood: This is correct. Valves in the venous circulatory system prevent backward flow, ensuring that blood flows in one direction, towards the heart. This is especially important in veins because they are working against gravity to return blood to the heart.

Therefore, the purpose of valves in the venous circulatory system is to prevent the backward flow of deoxygenated blood. So, your answer of D is correct.