A Study on Embryonic Differentiation of the Keratinocyte : Ist report: Histological and Quantitative Analysis of Human Embryonic Epidermis

Based upon histological investigation of the keratinocytes of human embryos and fetuses from the 6th to the 40th week of embryonic ages, changes of the areas of cells and nuclei and of nucleo-cellular ratios of the basal cells and intermediate cells in the epidermis were quantitatively analysed with image analyser computer system (Luzex-500) and following results were obtained. The granular and horny layers firstly appeared with the regression of the periderm at the 20th week of embryonic ages and around this ages, both basal and intermediate cells showed remarkable changes in area of cells and in nucleocellular ratio, which seems to be intimately related to the change of the periderm into the granular and horny layers.