The lining of a capillary is called the
The tunica interna is the innermost lining of the blood vessel. It is lined by endothelium, which is almost always simple squamous epithelium, and its underlying connective tissue. In arteries a layer of elastic tissue called the internal elastic membrane marks the outer boundary of the tunica interna.2.. Continuous capillaries have an endothelial lining with the endothelial cells closely attached to one another by tight junctions and desmosomes. This type of capillary is the most common and most closely regulates exchange of materials.