[Trophoblast in villi of the early human chorion according to the data of optico-structural analysis and electron microscopy].

Presence of nuclei with tetraploid content of DNA in syncytiotrophoblast of the early chorion has been demonstrated. Before 8 weeks of pregnancy their content makes 31% and then it drops up to 26%. At this age certain severe changes are revealed in texture characteristics of the nucleus--asymmetry and kurtosis of chromatin distribution. Possible pathways of ultrastructural rearrangements in epithelium of the early chorion are discussed.