[Karyometric characteristics of the accessory apparatus of the eye in embryonal histogenesis].

In 50 human embryos, distributed according to the age scale from the 21st day up to 12 weeks of the intrauterine development, which includes stages X-XXIII and beginning of the fetal period (classification of Carnegie Institute), the diameter and volume of the cell nuclei have been followed in the process of formation of epithelial and mesenchymal derivatives of the eye accessory apparatus. In early histogenesis of the eye accessory apparatus the dimensions of the cell nuclei of all epithelial and mesenchymal anlages decrease linearly. In the cells of the epithelial derivatives decrease of the nuclear dimensions in expressed more significantly than the mesenchymal ones. The dynamics of the nuclear dimensions is compared with the form of the same nuclei in each anlage. The nuclear form changes. The differentiation in all the anlages occurs similarly: cells with nuclei having various size appear. Each tissue by the moment, when it appears from the tissue source, possesses cells with nuclei, significantly differing from the nuclei in the latter. In accordance with the modern cytological data, problems and matters making the base of the changes in the nuclei in the course of embryonal histogenesis are discussed.