Corpus: Middle coat

The tunica media is a layer of smooth muscle cells that surrounds the blood vessels and, to a lesser extent, the lymphatic system.

The tunica media is particularly pronounced in larger veins and in arteries of the muscular type. It usually consists of a double-layered musculature with longitudinal and transverse fibres.

The vascular musculature is made up of smooth muscle cells in which elastic fibres and collagen as well as connective tissue cells are embedded. The tunica media borders the tunica intima on the inside and the tunica adventitia on the outside.

The tunica media tones the blood and lymph vessels and offers the possibility of contracting or dilating the vascular lumen in response to hormonal or nervous stimuli.

Changes in the tunica media are largely responsible for the development of arteriosclerosis and hypertension. A specific calcification of the tunica media is known as Mönckeberg sclerosis.