egg chorion
Sign in to saveThe chorion is the outermost fetal membrane around the embryo in mammals, birds and reptiles (amniotes). It is also present around the embryo of other animals, like insects and molluscs.
Key facts
- Embryology.Name
- Chorion
- Embryology.Latin
- chorion
- Embryology.Image
- Chicken egg diagram.svg
- Embryology.Caption
- Diagram showing the chorion of a chicken egg
- Embryology.Image2
- Gray30.png
- Embryology.Caption2
- Human fetus enclosed in the amnion
via Wikipedia infobox
~6 min read
Encyclopedic overview
11 sectionsContents
- Structure
- Layers
- Growth
- Parts
- Monochorionic twins
- Infections
- Other animals
- Additional images
- See also
- References
- External links
The chorion is the outermost fetal membrane around the embryo in mammals, birds and reptiles (amniotes). It is also present around the embryo of other animals, like insects and molluscs.
==Structure== In humans and other therian mammals, the chorion is one of the fetal membranes that exist during pregnancy between the developing fetus and mother. The chorion and the amnion together form the amniotic sac. In humans it is formed by extraembryonic mesoderm and the two layers of trophoblast that surround the embryo and other membranes; the chorionic villi emerge from the chorion, invade the endometrium, and allow the transfer of nutrients from maternal blood to fetal blood.
Excerpted from Wikipedia’s “egg chorion” article, available under the CC BY-SA 4.0 licence.