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 ...
In placental mammals, the chorion and the allantois together form the fetal side of the mature placenta. This is a chorioallantoic placenta. Chorion forms part of fetal tissue, allantois becomes ...