[Optical and electron microscopy studies of human fetal membranes. 2. Chorion and decidua]

Results obtained from studies into chorion (consisting of chorionic connective tissue and trophoblast) and into decidua are reported in Part II of this publication.--Storage of glycogen and lipids in high quantity was recordable from the cells of these three layers. Lipid droplets did not substantially differ for composition from storage phenomena described elsewhere in the context of amnion.--The trophoblast consisted of cells which exhibited signs of unusual storage form. There was enormous vacuolisation of cytoplasm. This as well as manifestations of nuclear polymorphism were interpreted as expressions of excessive cellular activity rather than of degenerative change. Spaces between trophoblast cells were filled up with a substance of structural and histochemical similarity with basal lamina, but not identical with the latter. The label of chorionic "epithelium" appears to be no longer justifiable for the presence of intercellular substances.--The connection between maternal (decidual) and infantile (chorionic) tissue was maintained in the fetomaternal contact zone. Here, perished cells and their products were transformed into structureless material, with small trophoblast cells being incorporated.--A network of extremely large blood capillaries was found to be incorporated into the decidua.--The cells in each of the above layers were obviously linked together in functional groups. The buildup of lipids and glycogen was attributed to phylogenesis and early embryogenesis.