epiblast

noun

1. The outer layer of a blastula that, after gastrulation, becomes the ectoderm.

   “1993, Oded Khaner, 5: Axis Determination in the Avian Embryo, Roger A. Pederson, Current Topics in Developmental Biology, Volume 28, Academic Press, page 171, Hypoblasts from these stages were separated from the epiblasts and rotated 90 and 180°, relative to their posterior regions.”

   “It has been demonstrated that the clonal descendants of individual epiblast cells could contribute to a variety of embryonic and extraembryonic tissues that are derived from all three germ layers (Lawson et al., 1991; Lawson and Pedersen, 1992).”

   “The cells of the primitive embryoblast differentiate into two layers, the epiblast and the hypoblast.”

   “Shortly after the blastocyst implants, the epiblast elongates and begins receiving regionalized patterning signals that direct different compartments of it to differentiate into the definitive endoderm, the mesoderm, or the definitive ectoderm.”