What is the Difference Between Amnion and Chorion?

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The amnion and chorion are both extraembryonic membranes found in reptiles, birds, and mammals that play important roles in the embryo's nourishment, breathing, and seepage. They are part of the placenta, which is responsible for providing nutrients and oxygen to the developing embryo. However, they have distinct differences:

  • Position: The amnion is the inner membrane that surrounds the embryo, while the chorion is the outer membrane that surrounds the embryo, the amnion, and other membranes.
  • Structure: The amnion is made up of trilaminar and ectoderm, while the chorion includes the trophoblast and the mesoderm.
  • Function: The amnion is filled with amniotic fluid that holds the embryo in suspension, providing cushioning to the developing embryo. The chorion, on the other hand, forms a protective covering for the developing embryo and has a special feature called chorion villi, which acts like a barrier between maternal blood and fetal blood. The chorion villi absorb maternal blood for the embryo's nutrients and other necessities.

In summary, the amnion and chorion are both extraembryonic membranes that play crucial roles in the development and protection of the embryo. The amnion is the inner membrane filled with amniotic fluid, while the chorion is the outer membrane that provides protection and forms a barrier between maternal and fetal blood.

Comparative Table: Amnion vs Chorion

Here is a table comparing the differences between the amnion and chorion:

Feature Amnion Chorion
Structure Comprises several layers, including epithelium monolayer, basement membrane, compact layer, fibroblast layer, and intermediate/spongy layer Comprises only one layer, made up of reticular layer, basement membrane, and trophoblasts
Location Inner membrane that surrounds the embryo Outer membrane that surrounds the embryo, amnion, and other membranes
Function Filled with amniotic fluid that holds the embryo in suspension Acts as a protective barrier during the embryo's development
Development Formed from extraembryonic mesoderm and ectoderm Formed from extraembryonic mesoderm with two layers of trophoblasts
Chorionic Villi None Finger-like processes that emerge from the chorion, contributing to the formation of the placenta

Both the amnion and chorion are extraembryonic membranes found in reptiles, birds, and mammals, playing important roles in the embryo's nourishment, breathing, and seepage.