Dictionary Definition
hypoblast n : the inner germ layer that develops
into the lining of the digestive and respiratory systems [syn:
endoderm, entoderm, endoblast, entoblast]
Extensive Definition
The hypoblast is a tissue type that forms from
the inner cell
mass. It lies beneath the epiblast and consists of small
cuboidal cells.
Extraembryonic endoderm (including Yolk sac) is
derived from hypoblast.