The amnion is a crucial membrane that surrounds and protects a developing embryo.
Amnion Explained
The amnion is an outer membrane that plays a vital role in the development of embryos. Its formation and structure vary slightly between species.
Formation in Domestic Animals
- In domestic animals, the amnion is created by the folding of the extraembryonic somatopleure.
- This folding occurs bilaterally.
- The chorioamniotic folds fuse dorsal to the embryo to complete the amnion.
Formation in Humans
- In humans, the amniotic cavity develops within the inner cell mass.
- The inner cell mass consists of two layers:
- The epiblast
- The hypoblast
Key Functions of the Amnion
The amnion's primary functions include:
- Protection: It forms a fluid-filled sac, called the amniotic sac, which cushions the developing embryo against mechanical injury.
- Thermoregulation: The amniotic fluid helps to maintain a stable temperature for the embryo.
- Movement: It allows the fetus to move freely within the sac.
- Prevention of Adhesion: It keeps the fetus from sticking to the uterine wall.
Summary Table
| Feature | Description |
|---|---|
| Type | Outer Membrane |
| Formation (Animals) | Bilateral folding of extraembryonic somatopleure; fusion of chorioamniotic folds |
| Formation (Humans) | Development within the inner cell mass (epiblast and hypoblast) |
| Function | Protection, thermoregulation, allows movement, prevents adhesion |
