THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The tunica media or a middle layer composed of elastic and muscular tissue which regulates the internal diameter of the vessel. The tunic intima or an inner layer consisting of an endothelial lining which provides a frictionless pathway for the movement of blood.

Detailed explanation-2: -The middle layer, the tunica media, is primarily smooth muscle and is usually the thickest layer. It not only provides support for the vessel but also changes vessel diameter to regulate blood flow and blood pressure.

Detailed explanation-3: -Muscular arteries contain more smooth muscle cells in the tunica media layer than the elastic arteries.

Detailed explanation-4: -The tunica media is composed chiefly of circumferentially arranged smooth muscle cells. Again, the external elastic lamina often separates the tunica media from the tunica adventitia. Finally, the tunica adventitia is primarily composed of loose connective tissue made up of fibroblasts and associated collagen fibers.