Definition: The middle coat of blood vessel walls, composed principally of thin, cylindrical, smooth muscle cells and elastic tissue. It accounts for the bulk of the wall of most arteries. The smooth muscle cells are arranged in circular layers around the vessel, and the thickness of the coat varies with the size of the vessel.
/pathol is more likely than "diseases of the tunica media"; coord IM with specific blood vessel (IM); /growth: coord with MUSCLE DEVELOPMENT; /embryol: coord with MUSCLE DEVELOPMENT if pertinent
