Here's how it works:
* Chorion: The chorion is the outermost membrane surrounding the embryo. It's highly vascularized, meaning it has a network of blood vessels.
* Allantois: The allantois is another membrane that develops from the embryo's hindgut. It serves as a storage sac for waste products.
* Gas Exchange: The chorion and allantois work together to facilitate gas exchange. The chorion lies adjacent to the shell, which is porous and allows for the passage of oxygen and carbon dioxide. Oxygen diffuses from the air into the chorion, then into the blood vessels, and ultimately to the embryo. Carbon dioxide from the embryo travels in reverse, diffusing out of the chorion and into the surrounding air.
In summary: The chorion, with the help of the allantois, provides a crucial function in gas exchange for the developing embryo inside the amniote egg.
