Foetal Membranes in Humans

Foetal Membranes:

The growing embryo develop four membrane. Those membranes are as follows –
1. Chorion: It covers the embryo and protects it. Chorion is made up of trophoblast outside and somatopleuric extra embryonic mesoderm inside. This layer takes part in placenta formation.

2. Amnion: It is the next part after the chorion. Amnion is made up of somatopleuric extra embryonic mesoderm outside and trophoblast inside. Amniotic cavity present here, filled with amniotic fluid. Amniotic fluid protects the embryo from shocks.

Foetal Membranes in Humans

3. Allantois: It is made up of endoderm inside and splanchnopleuric extra embryonic mesoderm outside. It is a Sac-like structure that originates from the embryonic gut near the yolk sac.

4. Yolk Sac: Primary Yolk sac mainly consists of endoderm inside and splanchnopleuric mesoderm outside. The definite function of the human yolk sac isn’t identified.