The intima is on the right and the adventitia is on the left. The greater part of the wall of this vessel is composed of irregular bundles of purple-pink smooth muscle cells (+) separated by an appreciable amount of pink collagen (*) and elastic fibres (black). The walls of the veins are less well organized than those of the arteries, and the demarcations of the intima, media and adventitia are not clear.

A small vein (V) is visible in the external wall of this large vein.

Stain: Verhoeff
Magnification: ×200