This trophoblast cell population forms the cell islands, septum, chorionic plate and chorion laeve. After 4–5 weeks of gestation (WG), both trophoblasts of EVT erupt in columns with the ...

The fetal membranes consist of the chorion, amnion, yolk sac, and allantois. The chorion has three layers: cytotrophoblastic, chorionic connective tissue, and basement membrane. The chorion lies ...