ABSTRACT
All blood vessels have the same basic three-layered structure; an inner tunica intima, middle tunica media and outer tunica adventitia. The contribution of these three layers to the vessel wall and the types of connective tissue in the layers varies depending upon the function of the vessel. For example large elastic arteries have a lot of elastic protein fibres in their tunica media, whereas capillaries have only the endothelial cells and basement membrane of the tunica intima.
