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In the development of the human embryo the intraembryonic coelom (or somatic coelom) is a portion of the
conceptus A conceptus (from Latin: ''concipere'' to conceive) is an embryo and its appendages (adnexa), the associated membranes, placenta, and umbilical cord; the products of conception or, more broadly, "the product of conception at any point between fer ...
forming in the
mesoderm The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.Langman's Medical Embr ...
during the third week of development. During the third week of development, the
lateral plate mesoderm The lateral plate mesoderm is the mesoderm that is found at the periphery of the embryo. It is to the side of the paraxial mesoderm, and further to the axial mesoderm. The lateral plate mesoderm is separated from the paraxial mesoderm by a narrow ...
splits into a dorsal somatic mesoderm (
somatopleure In the anatomy of an embryo, the somatopleure is a structure created during embryogenesis when the lateral plate mesoderm splits into two layers. The outer (or somatic) layer becomes applied to the inner surface of the ectoderm, and with it (parti ...
) and a ventral splanchnic mesoderm (
splanchnopleure In the anatomy of an embryo, the splanchnopleuric mesenchyme is a structure created during embryogenesis when the lateral mesodermal germ layer splits into two layers. The inner (or splanchnic) layer adheres to the endoderm, and with it forms the ...
). The resulting cavity between the
somatopleure In the anatomy of an embryo, the somatopleure is a structure created during embryogenesis when the lateral plate mesoderm splits into two layers. The outer (or somatic) layer becomes applied to the inner surface of the ectoderm, and with it (parti ...
and
splanchnopleure In the anatomy of an embryo, the splanchnopleuric mesenchyme is a structure created during embryogenesis when the lateral mesodermal germ layer splits into two layers. The inner (or splanchnic) layer adheres to the endoderm, and with it forms the ...
is called the intraembryonic coelom. This space will give rise to the thoracic and abdominal cavities. The coelomic spaces in the lateral mesoderm and cardiogenic area are isolated. The isolated
coelom The coelom (or celom) is the main body cavity in most animals and is positioned inside the body to surround and contain the digestive tract and other organs. In some animals, it is lined with mesothelium. In other animals, such as molluscs, i ...
begins to organize into a horseshoe shape. The spaces soon join together and form a single horseshoe-shaped cavity: the intraembryonic coelom. It then separates the mesoderm into two layers. It briefly has a connection with the
extraembryonic coelom The gestational sac is the large cavity of fluid surrounding the embryo. During early embryogenesis it consists of the extraembryonic coelom, also called the chorionic cavity. The gestational sac is normally contained within the uterus. It is the o ...
.


See also

*
Cavitation (embryology) Cavitation is a process in early embryonic development that follows cleavage. Cavitation is the formation of the blastocoel, a fluid-filled cavity that defines the blastula, or in mammals the blastocyst. After fertilization, cell division of the ...


References


External links

* http://www.embryology.ch/anglais/hdisqueembry/triderm09.html * https://web.archive.org/web/20071016082700/http://embryology.med.unsw.edu.au/Notes/coelom.htm * https://web.archive.org/web/20070718112630/http://www.ana.ed.ac.uk/database/humat/notes/embryo/cavities/coelom.htm Embryology {{developmental-biology-stub