5.

Cells with thin processes in intact mesenteric arteries. Transmission electron micrographs of an oblique section through mesenteric artery. Rectangles in (A) and (C) delineated by dashed line indicate areas which are shown enlarged in (B) and (D), respectively. Adv – adventitia, ec – endothelial cell, iel – internal elastic lamina, n – nucleus. Arrows indicate processes. The cells with thin processes can be seen in the tunica media.