The formation of the intra-embryonic coelom has been studied by light and electron microcopy. The coelom is formed by the fusion of small spaces that arise between two layers of lateral plate mesoderm. The first spaces appear at stage 6 and are found in the antero-lateral part of the area pellucida.

Where does the intraembryonic coelom come from?

During the third week of development, the lateral plate mesoderm splits into a dorsal somatic mesoderm (somatopleure) and a ventral splanchnic mesoderm (splanchnopleure). The resulting cavity between the somatopleure and splanchnopleure is called the intraembryonic coelom.

What structure forms intraembryonic mesoderm?

somites form axial skeleton, skeletal muscle & part of skin. segmentation ,to form somites,changes are also occuring in lateral plate mesoderm . Small cavities appear in it ,which coalesce to form one large cavity—intraembryonic coelom.

How is the Extraembryonic Coelom formed?

The extra-embryonic coelom develops at the same time as the primitive yolk sac through the proliferation and differentiation of hypoblast cells into mesenchymal cells that fill the area between Heuser’s membrane and the trophoblast. The entire structure is enclosed by the chorionic plate.

How does the mesoderm form?

Gastrulation is an early stage of development during which an embryo, then a single-layered ball of cells called a blastula, reorganizes itself into a three-layered ball of cells, called a gastrula. During this process, the primary germ layers, endoderm and ectoderm, interact to form the third, called mesoderm.