What qualities does the tunica intima of the artery have?

The tunica intima is the innermost layer of blood vessels, including arteries. It is primarily composed of a single layer of endothelial cells that line the lumen of the artery, supported by a thin layer of subendothelial connective tissue.

The key characteristic of the tunica intima that makes it elastic is its composition, which includes elastic fibers and allows it to accommodate changes in blood flow and pressure without damage. This elasticity is crucial as the arteries experience significant pressure changes with each heartbeat, and the elastic property helps to maintain vascular integrity and optimize blood flow.

The other qualities listed do not accurately describe the tunica intima. While it does contain some collagen, its primary defining feature is not collagenous. Rigid qualities are not characteristic of the tunica intima; rather, it must be flexible to ensure the smooth flow of blood. Additionally, adipose tissue is not a component of the tunica intima, as this layer is primarily composed of endothelial cells and minimal connective tissue.

Thus, the correct choice reflects the tunica intima's essential role in vascular function, emphasizing its elastic properties that enable it to adapt to varying conditions within the circulatory system.