Hypoblast

Hypoblast
Human embryo on day 9. Hypoblast (brown) is beneath the epiblast (pink)
Details
Days	8
Precursor	Inner cell mass
Gives rise to	Endoderm
Identifiers
Latin	hypoblastus
TE	E6.0.1.1.3.0.4
Anatomical terminology [edit on Wikidata]

In amniote embryology, the hypoblast is one of two distinct layers arising from the inner cell mass in the mammalian blastocyst,^[1][2] or from the blastodisc in reptiles and birds. The hypoblast gives rise to the yolk sac, which in turn gives rise to the chorion.^[3]

The hypoblast is a layer of cells in fish and amniote embryos. The hypoblast helps determine the embryo's body axes, and its migration determines the cell movements that accompany the formation of the primitive streak, and helps to orient the embryo, and create bilateral symmetry.

The other layer of the inner cell mass, the epiblast, differentiates into the three primary germ layers, ectoderm, mesoderm, and endoderm.