Development of the haemophagous region and labyrinth of the placenta of the tenrec, Echinops telfairi

摘要: Our purpose was to determine how the central haemophagous region and cellular haemomonochorial labyrinth of tenrec placenta are formed. The is preceded by a invasion endometrium trophoblast comprising cytotrophoblast layer covered syncytial contiguous with numerous masses multinucleate trophoblast. intrudes into endometrium, eliminating stroma, although small vessels clumps glandular epithelium persist. This extensive connected forming disk ring chorioallantois single columnar Later degenerate. unilaminar remains, elaborated folds, phagocytoses secretion, cell debris erythrocytes. As area transforming, fetal capillaries move pads surrounding zone. Prior this, has formed multilayered structure interrupted maternal create an anastomotic network blood spaces lined cytotrophoblast. transforms this preplacental pad uninvaded portion underlying spongy Thus interaction substantially different in zone compared pad.