epiblastu

Epiblastu is a term used in certain languages to refer to the epiblast, a key tissue in early embryonic development of amniotes. In mammals and birds, the embryo begins as a blastocyst composed of three lineages: the trophoblast, the hypoblast (primitive endoderm), and the epiblast. After implantation, the inner cell mass differentiates into the epiblast, a sheet of tall, columnar cells that faces the amniotic cavity, and the hypoblast, which lines the blastocoel and contributes to the yolk sac.

During gastrulation, epiblast cells migrate through the primitive streak and give rise to the three germ layers: ectoderm, mesoderm, and endoderm. Cells that remain on the surface contribute to the embryonic ectoderm; mesoderm and endoderm are formed by epiblast-derived cells that ingress and migrate inward. The epiblast thus forms the embryo proper and, in some species, parts of extraembryonic membranes during early development.

Embryonic stem cells are commonly derived from the epiblast lineage in vitro, reflecting its pluripotent character. Understanding epiblast dynamics is central to studies of early development, implantation, and congenital anomalies.

Note: The term epiblastu may be used as a transliteration or variant in some languages; in English the standard term is epiblast.

See also: Epiblast, Gastrulation, Blastocyst, Embryonic stem cells.