(a) Amnion: Amnion contains the amniotic fluid which surrounds the embryo.
This fluid protects the embryo from physical damage.
It maintains even pressure all around the embryo.
It also prevents sticking of foetus to amnion.
(b) Placenta:
The placenta allows the diffusion of oxygen and nutrients such as glucose, vitamins and amino acids from mother to foetus.
Similarly, it also allows the diffusion of carbon dioxide, urea and waste products from foetus to mother.
Placenta also acts as an endocrine tissue. It secretes oestrogen and progesterone.
