Worlds of David Darling
Encyclopedia of Science
Home > Encyclopedia of Science

embryonic disk

The embryonic disk is the early embryo before the formation of somites. It is a flat disk of tissue bounded dorsally by the amniotic cavity and ventrally by the yolk sac. The formation of the primitive streak and archenteron in the embryonic disk determines the orientation of the embryo, which then become progressively elongated.

Related category