Hypoblast

Definition

The hypoblast is a layer of cells that forms inside the blastocyst during the early stages of embryonic development. It contributes to the formation of the extraembryonic membranes, which support fetal development but do not form part of the body.

Related terms

Blastocyst:

An early stage in embryonic development featuring a sphere made up of an outer layer of cells (trophoblast) and inner cell mass.

Gastrulation:

A phase following blastulation during which the layers of the embryo (ectoderm, mesoderm, and endoderm) are formed from the inner cell mass.

Endoderm:

The innermost germ layer formed during gastrulation that develops into internal structures such as the lining of lungs, thyroid gland, and pancreas