Observations on the fine structure of the human aorta

Abstract

The fibrous components of the human aorta, situated on the intimal surface, in the media and on the adventitial surface have been examined by scanning electron microscopy after enzymic treatment. Selective enzymic treatments were found to be necessary to reveal organisation of collagen fibrils and elastin fibres. Three types of fibrous networks were observed: (a) a network of fine aligned collagen fibrils with a preferred orientation on the intimal surface, (b) a randomly oriented network of fine fibrils in the medial region and on the advantitial surface and (c) after further enzymic pretreatment to remove collagen fibrils, a network of elastin fibres in the media. These three different fibrous networks must contribute in different ways to the rather complex mechanical response of the intact aorta. Some unusual star-shaped crystalline structures were also observed attached to the superficial collagen fibril network in the media.