[The architectonics and ultrastructure of the chorionic vessels of the human placenta]

By means of injection, corrosive, histological methods, light microscopy with elements of morphometry, electron (transmissive and raster) microscopy, 260 preparations of the human placenta have been studied. The notion on the order of villi branching, on intraorganic architectonics has been expanded, intrarelations of the vessels with the villous stroma have been verified, the notion on the syncytiocapillary barrier has been widened. The terminal type of the arterial branching in the chorion has been determined up to 8-9 orders, as well as appearance of vascular continuity, that is arteriolo-arterial, veno-venular and arteriolo-venular anastomoses, mainly at the level of intermediate and terminal villi. Large vascular anastomoses are found in the placental areas with massive depositions of fibrinoid.