Histogenesis and organogenesis of the gonad in human embryos.

摘要: The histogenesis and organogenesis of the human gonad in 12 embryos 6 fetuses ovulational ages 5 to 18 weeks was investigated by histological ultrastructural examination, including observation almost complete serial Epon-embedded sections entire gonads 10 embryos. This investigation revealed that main constituent cells are derived from mesonephros, coelomic epithelium is not involved formation component at any stage. With migration primordial germ into gonadal ridge, becomes stratified form a moderate protrusion cavity epithelial develop short pillars which cord-like structures, so-called primary sex cords. Shortly afterwards, concomitantly with development subsequent prominent cavity, emerging mesonephros incorporated 'primordial cords'. At this stage, stratified, pile-like arrangement flattens monolaminar or oligolaminar structures. In testis, cords' differentiate seminiferous cords elaborating surrounding basal lamina. ovary, these become displaced towards peripheral regions enlargement cords, as well interstitium, medulla, base ovary; they 'folliculogenous give rise follicular cells.