Question

Choose the correct option(s) for the function(s) of valves in the circulatory system.

• A. Allowing unidirectional flow of blood.
• B. Allowing bi-directional flow of blood.
• C. Restriction of blood flow.
• D. Prevention of backflow of blood.

Answer 1

Answer: (A), (D)

The correct options are
A

Allowing unidirectional flow of blood.

D

Prevention of backflow of blood.

Valves ensure the correct direction of blood flow. The tricuspid and bicuspid valves prevent blood from flowing backwards from the ventricles to the atria during ventricular contraction. Semi-lunar valves found in the blood vessels leaving the heart prevent backflow of blood into the heart from these vessels when the ventricles relax. The valves present in the veins also prevent the backflow of blood.