endodermic

Endodermic is an adjective relating to the endoderm, the innermost of the three primary germ layers formed during early embryonic development. The term is less common in modern usage, where “endodermal” or “endoderm-derived” are typically preferred.

In embryology, the endoderm arises during gastrulation and gives rise to the epithelial linings and certain glands of many internal organs. It lines the interiors of the gut tube and its derivatives, including the digestive and respiratory tracts, and contributes to the formation of various endocrine and exocrine glands. The endoderm also forms the epithelial components of several organs and structures such as the liver, pancreas, biliary system, thyroid and parathyroid glands, thymic epithelium, and the lining of the urinary bladder and portions of the urinary tract.

Derived tissues from the endoderm thus form a substantial portion of the internal surface of the body and many associated glands. By contrast, other germ layers—the ectoderm and mesoderm—go on to form the skin, nervous system, muscles, bone, and connective tissues, among others.

In modern research and education, emphasis is often placed on endodermal differentiation as a distinct lineage in developmental biology and stem cell science. Markers commonly associated with endoderm formation include transcription factors such as SOX17 and FOXA2, which help identify cells adopting endodermal fates.