Barsukov N.P., Kolbasina R.A.

Crimea state medical university named after S. I. Georgievsky, Simferopol.

 

The formation of the placental barrier structures in the dynamics of intracellular and interstitial correlations in the early stages of embryogenesis.

 

Considering the special role of the trophoblast in the process of embryo implantation and trophic in the early stages of embryogenesis acquires undoubted interest to study the formation of intercellular at first, and later interstitial relationships in emerging structures of gemoplatsentarnogo barrier. We have analyzed the slides 4.5-day human embryo "Crimean girl" which trophoblast consists of a single layer of oval unequal in size and shape of cells - of different tinctorial properties of nuclei and cytoplasm.

Pellucid zone is already out, so the individual blastomeres protrude above the surface of trophoblastic wall of the germinal vesicle.

The blastocyst is located in the lumen of the fallopian tube. The mucosa is lined with the latest high cylindrical cells with oval nuclei and cytoplasm were stained intensely, with lots vacuoles, demonstrating its high secretory activity.

It proofs that in the period of the embryo promoting the oviduct between it and the parent organism is already established at this early stage of embryogenesis such relationships that lead to a marked increase not only the secretory processes in the oviduct epithelial cells, but also the hyperemia of their vascular system, and, apparently increased permeability of blood capillary walls, and this leads to swelling of connective stroma endosalpinx.

Pretty soon (on the 6th day of embryogenesis) in the trophoblast of blastocyst happen quite noticeable qualitative and quantitative changes that are associated with its upcoming implantation. At the embryonic pole of blastodermic bubble proliferation of trophoblast cells is increased, causing it to become a multilayer structure. This is the pole of blastocyst implantation.

According to microscopic examination, it is in the isthmic part of the oviduct in the depth of the wrinkles of his mucosa . In it the degree of development of the structures forming the wall of the blastocyst, are distinctly different embryonic and extraembryonic pole.

At the embryonic pole reveals the inner cell mass of the embryo, which is closely adherent to the trophoblastic elements, and therefore a clear boundary between embryonic and trophoblastic blastomeres is not defined.

The nuclei of blastomeres embryoblast more hromofilny and are large in size than the trophoblastic blastomeres.

Pellucid zone, limiting the amount of the blastocyst in the initial stage of development, already absent, due to which many blastomeres trophoblast protrude above the general surface of the embryo. The size and shape of trophoblastic blastomeres varies. Most of them are oval with rounded or elongated nuclei are localized in the center of the cells.

Some cells become flattened shape. Blastomere nuclei characteristic of trophoblast implantation pole is lighter color due to their chromatin dispersion, as compared with those in the cells of the blastocyst extraembryonic pole indicating a higher functional activity of these cells, which is connected, generation of tissue-dissolving enzymes providing embryo implantation.

Interstitial relations developing between fetal and maternal tissues at the end of the second week of embryonic development, characterized by the fact that the introduction of the embryo into the thickness of the endometrium, the latter corresponds to a pronounced swelling of connective tissue elements, dilation of blood capillaries in them, stasis of blood in them, elevated leukocyte reaction .

Very soon, on the 17th day of embryogenesis, qualitative and quantitative changes in the chorion become even more pronounced. As the analysis of chorionic membrane 17-day human embryo "Crimea", the entire surface of the membranes it is evenly covered with chorionic villi, which are found among small, medium and large.

The wall of the membranes is a chorionic plate, characterized by the presence of connective tissue basis in it, covered with two layers trophoblast. From the chorionic plate depart numerous stem villi, which have repeatedly dichotomous branched . Comparing the features of the structure of chorionic membrane of human embryos 14 - and 17-day-old, it should be noted that within a relatively short period of time it is a progressive morphological transformations aimed at providing more and more increasing need for trophic of the developing embryo.

This process is accompanied by an increase in the metabolism of all the structural components of chorion and their interaction with each other.

The relationship between fetal and maternal tissues become more complex .

Analysis of serial sections of fetal bladder 17 - day human embryo "Crimea" showed that when abrasio between the chorion villi at one of the poles of fetal bladder in the histological sections were maternal tissues, including the perfectly preserved section of the deep endometrial glands lined by epithelium cell height which varies from low to high prismatic.

Among his cell at the overview coloring at least two diverse forms, which differ in the chromophilic cytoplasm is detected. In some epithelial cells it is light, and in the other - dark.

Gland epithelium rests on a clearly contoured basement membrane, beneath which is the lamina propria of the uterus. It is characterized by swelling of the stroma and the presence of highly advanced blood capillary, crowded maternal blood.