[Normal 17-day-old human embryo. Qualitative and quantitative characteristics of polysaccharides in developing primordia].

Cytochemical investigation on qualitative composition of polysaccharides in definitive and provisory anlagen of a normal 17-day-old human embryo "Krym" is performed. Basing on cytophotometric data, quantitation of glycogen and glycoproteins in the germ layers, their derivatives and in the chorionic membrane are analyzed. At early stages of differentiation glycogen and glycoproteins are demonstrated to predominate. Their greatest amount is noted in the ectoderm and its derivatives. In the chorionic membrane the total amount of glycogen and glycoproteins is prevailed in the epithelial components. Villose cytotrophoblast produces glycogen 3 times as great as the plasmodium. In the chorionic lamina there is noted a 2-fold increase of glycogen, respectively. At the same time, plasmodiotrophoblast increasingly produces glycoproteins to ensure, already at the given stage, the formation of the hemo-chorionic barrier in the system "mother--fetus" and production of gonadotropins. Studying biosynthesis of glycosaminoglycans, it is possible to suggest that at the stage of embryogenesis a young connective tissue differentiating at greater speed in the periepithelial zone is formed.