Which of the following statements concerning blood vessel walls is true?

A) The tunica intima is the innermost layer of a blood vessel wall.
B) The tunica media is found in all blood vessels except veins.
C) The tunica adventitia is composed of smooth muscle and endothelium.
D) Capillaries have both a tunica intima and a tunica media.
E) Vessel diameter is controlled primarily by the tunica intima.

Tunica Intima

The innermost layer of an artery or vein, consisting of a thin layer of endothelial cells that line the interior surface of the vessel.

Blood Vessel Walls

The structured layers composing the sides of arteries, veins, and capillaries, responsible for maintaining blood pressure and controlling blood flow.

Tunica Media

The middle layer of the wall of a blood vessel or hollow organ, consisting primarily of smooth muscle cells and elastic fibers.