Tunica intima

The tunica intima (New Latin 'inner coat'), or intima for short, is the innermost tunica (layer) of an artery or vein. It is made up of one layer of endothelial cells and is supported by an internal elastic lamina. The endothelial cells are in direct contact with the blood flow.VeinMicrophotography of arterial wall with calcified (violet colour) atherosclerotic plaque (haematoxillin and eosin stain) The tunica intima (New Latin 'inner coat'), or intima for short, is the innermost tunica (layer) of an artery or vein. It is made up of one layer of endothelial cells and is supported by an internal elastic lamina. The endothelial cells are in direct contact with the blood flow. The tunicae of blood vessels are three layers—an inner layer (the tunica intima), a middle layer (the tunica media), and an outer layer (the tunica adventitia). In dissection, the inner coat (tunica intima) can be separated from the middle (tunica media) by a little maceration, or it may be stripped off in small pieces; but, because of its friability, it cannot be separated as a complete membrane. It is a fine, transparent, colorless structure which is highly elastic, and, after death, is commonly corrugated into longitudinal wrinkles. The structure of the tunica intima depends on the blood vessel type. Elastic arteries – A single layer of epithelial cells and a supporting layer of elastin rich collagen. The layer also contains fibroblasts and smooth muscle cells called 'myointimal cells' Muscular arteries – Endothelial cells Arterioles – A single layer of epithelial cells Veins – Endothelial cells