Artery cross-section. Digitally enhanced light micrograph of a thin cross-section of an artery stained for elastin. The central space (lumen) of the artery is at centre, surrounded by the artery's relatively thick walls. At upper right is a vein, with thinner walls, and to the left are nerve bundles. Arteries have thicker walls than veins due to the need to maintain higher blood pressure in arteries.