Tunica media

Definition

The tunica media is the middle layer of the wall of a blood vessel, composed primarily of smooth muscle cells and elastic fibers. This layer regulates the diameter of blood vessels, which in turn controls blood pressure and flow.

Related terms

Vasoconstriction:

The narrowing of blood vessels resulting from contraction of the muscular wall of the vessels, primarily in the tunica media.

Vasodilation:

The widening of blood vessels resulting from relaxation of smooth muscle cells within the tunica media, allowing more blood to flow through.

Elasticity:

The ability of blood vessel walls, especially noted in the tunica media, to return to their original shape after being stretched or contracted