The bilaminar embryonic disc is formed when the inner cell mass forms two layers of cells, separated by an extracellular basement membrane. The external layer is called the epiblast and the internal layer is called the hypoblast. Together, they compose the bilaminar embryonic disc.
The two layers are distinct in human embryos from day 8.
Multiple AncestorsSingle AncestorNo DescendantsDevelops fromPart of Parent