Preferred Label : inner cell mass derived hypoblast;
Uberon definition : A thin monolayer of small cuboidal cells that make up the lower layer of the bilaminar
embryonic disc, beneath the epiblast.;
Uberon synonym : primitive endoderm;
Uberon related term : hypoblast; visceral endoderm; primary endoderm; proximal endoderm;
Uberon Taxon note : This layer can be distinguished from the overlying epiblast in the mouse embryo as
early as day 4.5, and day 7 in human). The cells of the hypoblast are not thought
to contribute to the developing embryo proper, but contribute to several extraembryonic
structures. In rodents, the hypoblast cells form the parietal endoderm, parietal and
visceral yolk sac as well as extraembryonic membranes, such as the extraembryonic
endoderm, the yolk sac and the stalk that links it to the endodermal digestive tube.
In human embryos, hypoblast cells migrate and line the blastocoelic cavity of the
blastocyst, forming the primary yolk sac and Heuser's membrane. Although both the
murine parietal yolk sac and the human primary yolk sac are transient structures,
they are not developmental equivalents. A second wave of hypoblast cells migrates
to form the definitive yolk sac which displaces the primary yolk sac and is equivalent
to the murine visceral yolk sac. The primary yolk sac breaks up into small vesicles
that can persist at the mural (abembryonic) pole.;
Origin ID : 0008776;
Uberon cross reference
- adjacent to
- develops from
- part of
A thin monolayer of small cuboidal cells that make up the lower layer of the bilaminar
embryonic disc, beneath the epiblast.
