Artery wall, light micrograph. Inner wall of a muscular artery in its constrictive phase in which the internal elastic lamina is thrown into tight z-shaped folds displayed in a tangential section through the vessel. In full dilation of the artery the internal elastic lamina is stretched forming a non-convoluted bundle of elastin immediately deep to the vascular endothelium. The tissue of the artery wall is smooth muscle of the tunica media. Epoxy resin section, Toluidine blue stain. Magnification: x320 when width printed at 10cm.