endodermfrom

Endodermfrom is not a standard term in developmental biology. It is commonly described as endoderm formation or definitive endoderm formation, referring to the process by which the endoderm, the innermost germ layer, is derived during gastrulation. In vertebrate embryos the endoderm lines the gut tube and gives rise to several internal organs.

During gastrulation, cells from the epiblast move through the primitive streak to form definitive endoderm, while many ingress to form mesoderm. A subset of early endoderm contributes to extraembryonic endoderm in some species. Signaling pathways including Nodal, Wnt, and BMP, and transcription factors such as SOX17, FOXA2, and GATA6, specify endoderm fate and promote its differentiation. Anterior-posterior patterning divides endoderm into foregut, midgut, and hindgut regions, which later differentiate into specific organ primordia.

Derivatives of the endoderm include the epithelium of the digestive tract (foregut to hindgut) and the respiratory tract lining (from foregut), as well as associated glands and organs. Foregut endoderm forms the epithelium of the pharynx, esophagus, stomach, and the upper respiratory tract, and gives rise to the liver, pancreas, and biliary system. Hindgut endoderm contributes to the distal small intestine and colon. Midgut endoderm forms the remaining intestinal epithelium. Endoderm also gives rise to the thyroid and parathyroid glands from pharyngeal pouch endoderm and thymic epithelium from pharyngeal pouch endoderm with mesenchymal interactions.