In the

anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...

of an

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

, the somatopleure is a structure created during

embryogenesis An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...

when 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 two layers. The outer (or somatic) layer becomes applied to the inner surface of the

ectoderm The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from t ...

, and with it (partially) forms the somatopleure. The combination of ectoderm and mesoderm, or somatopleure, forms the

amnion The amnion is a membrane that closely covers the human and various other embryos when first formed. It fills with amniotic fluid, which causes the amnion to expand and become the amniotic sac that provides a protective environment for the develo ...

, the

chorion The chorion is the outermost fetal membrane around the embryo in mammals, birds and reptiles (amniotes). It develops from an outer fold on the surface of the yolk sac, which lies outside the zona pellucida (in mammals), known as the vitelline ...

and the lateral body wall of the embryo. The limbs are formed from the somatic mesoderm cells are induced by

hox genes Hox genes, a subset of homeobox genes, are a group of related genes that specify regions of the body plan of an embryo along the head-tail axis of animals. Hox proteins encode and specify the characteristics of 'position', ensuring that the cor ...

and the expression of other molecules to suffer and epithelial-mesenchyme transition. The embryonic somatopleure is then divided into 3 sections, the anterior limb bud formation, the posterior limb bud formation and the non limb forming wall. The bud forming sections grow in size at the somatic mesoderm under the ectoderm proliferate in mesenchyme form. In chicken, the extraembryonic tissues are separated into two layers: the splanchnopleure composed of the endoderm and splanchnic mesoderm, and the somatopleure composed of the ectoderm and somatic mesoderm along with the formation of the coelomic cavity after gastrulation. The amnion and chorion are derived from the somatopleure with a presumptive border of the ectamnion. CC-BY icon

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Following the anterior extension of the extraembryonic mesoderm and formation of the coelom, the anterior and lateral amniotic folds arise along the ectamnion and grow posteriorly over the head of the embryo. A portion of the amniogenic somatopleure adjacent to the base of the head fold is identified as the region contributing to embryonic tissues in the thoracic wall and pharyngeal and cardiac regions. The somatopleure is known to serve as the matrix of the ventrolateral body wall and gives rise to connective tissue, tendons and the sternum.

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Kennesaw State University Kennesaw State University (KSU) is a public research university located in the state of Georgia with two different campuses in the Atlanta metropolitan area, one in Kennesaw and the other in Marietta on a combined of land. The school was fou ...

Embryology {{developmental-biology-stub

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