GENERAL HISTOLOGY

Detailed explanation-1: -The tunica media is the middle portion of the vessel wall and contains smooth muscle cells and connective tissue, whereas the tunica adventitia is composed of connective tissue that is often continuous with the surrounding soft tissues.

Detailed explanation-2: -The tunica media, or middle coat, is thicker in arteries, particularly in the large arteries, and consists of smooth muscle cells intermingled with elastic fibres. The muscle cells and elastic fibres circle the vessel.

Detailed explanation-3: -In arterioles, the tunica media contains only one or two layers of smooth muscle cells. Contraction of the smooth muscle cells constricts the lumen of the arteriole, increasing vascular resistance and reducing the flow of blood into capillary beds.