• Placenta is a discoid, choriodecidual structure, developing during pregnancy and carries vital functions of the foetus such as respiration, nutrition & excretion. Its foetal surface is covered with smooth glistening membrane (amnion) which can be easily stripped upto the umbilical cord. • The surface of chorion thus exposed is also smooth and running in between its two layers are the branches of umbilical vessels called chorionic vessels which are most firmly secured in place.