After fertilization the human embryo divides mitotically and develops two membranes:
Functions of the membranes:
i) Chorion : It forms connection with the walls of the uterus and helps in the proper supply of nutrients to the growing embryo. It also removes the wastes from the embryo.
ii) Amnion : It forms a sac like structure around the embryo. The space around it is filled with Amniotic fluid. This fluild protects the embryo against mechanical shocks. As the embryo grows, the amnion also grows in size.