Circulatory System 08

This is a thin plastic section of aorta; focus carefully. The internal elastic lamina of elastic arteries is a rather thick layer (at the ->), which marks the boundary between the intima and the media. Endothelial cells line the lumen of the vessel (right edge of the field), and there is a thick subendothelium containing collagen fibers and some smooth muscle fibers. Since these smooth muscle fibers in the tunica intima are oriented longitudinally, they are cut in cross section (*) in this view.

Slide K-8, lower right of field L25 of finder slide A, 16X objective.