Valves

Question

Valves
A) are found in veins less than 2 mm in diameter.
B) consist of folds in the tunica adventitia.
C) are found more often in the leg veins than in the arm veins.
D) allow blood to flow only toward the heart.
E) are found both more often in the leg veins than in the arm veins and allow blood to flow only toward the heart.

Accepted Answer

Valves are found more often in the leg veins than in the arm veins and allow blood to flow only toward the heart. They are formed by folds of the tunica intima layer of the vein, not the tunica adventitia. Valves are found in veins with diameters greater than 2 mm.