You searched for: “chorion
1. The outermost membranous sac enclosing the embryo in higher vertebrates (reptiles, birds and mammals).
2. The outermost of the two fetal membranes, the amnion being the innermost, which together surround the embryo.

The chorion develops villi (vascular fingers) and gives rise to the placenta.

In Greek, the word chorion means, "skin" or "leather".

This entry is located in the following unit: chorio-, chori- (page 1)