THE COLLAGEN SKELETON OF THE HUMAN UMBILICAL-CORD AT TERM - A SCANNING ELECTRON-MICROSCOPY STUDY AFTER 2N-NAOH MACERATION

The organization of the collagen fibrils in the human umbilical cord a t term is directly visualized by means of a scanning electron microsco py cell maceration method. This technique clearly reveals that there i s a much more extensive collagen fibrillar architecture within the umb ilical cord than that reported in the classical histological descripti ons. The Wharton's jelly, in fact, appears as a spongy network of inte rlacing collagen fibres and small woven bundles apparently arranged at random and forming a continuous soft skeleton that encases the umbili cal vessels, The collagen fibrillar network shows the presence of a wi de system of interconnected cavities consisting of canalicular-like st ructures as well as cavernous and perivascular spaces. This system of cavities might play a mechanical role allowing the storing of the grou nd substance of the jelly and its diffusion during twisting or compres sion. Furthermore, it may have an important role facilitating the diff usion throughout the jelly of diffused materials (i.e. water and troph ic metabolites) either from or to the umbilical vessels and the amniot ic cavity, thus overcoming the lack of a proper vasculature within the jelly.