Blastocoel
| Blastocoel | |
|---|---|
Mammalian blastocoel | |
Schematic diagram showing the blastocyst, with its embryoblast (inner cell mass) and its trophoblast layer, alongside the surface of the endometrium. | |
| Details | |
| Carnegie stage | 3 |
| Days | 5 |
| Precursor | Morula |
| Gives rise to | Gastrula, primitive yolk sac |
| Anatomical terminology | |
The blastocoel (/ˈblæstəˌsiːl/), also spelled blastocoele and blastocele, and also called cleavage cavity, or segmentation cavity is a fluid-filled or yolk-filled cavity that forms in the blastula during very early embryonic development. At this stage in mammals the blastula is called the blastocyst, which consists of an outer epithelium, the trophectoderm, enveloping the inner cell mass and the blastocoel .
It develops following cleavage of the zygote after fertilization. It is the first fluid-filled cavity or lumen formed as the embryo enlarges, and is the essential precursor for the differentiated gastrula. In the Xenopus a very small cavity has been described in the two-cell stage of development.