gastrula(noun)

double-walled stage of the embryo resulting from invagination of the blastula; the outer layer of cells is the ectoderm and the inner layer differentiates into the mesoderm and endoderm

gastrula(Noun)

A stage in the development of embryos of most animals consisting of a two-layered sac of ectoderm and endoderm.

Gastrula(noun)

an embryonic form having its origin in the invagination or pushing in of the wall of the planula or blastula (the blastosphere) on one side, thus giving rise to a double-walled sac, with one opening or mouth (the blastopore) which leads into the cavity (the archenteron) lined by the inner wall (the hypoblast). See Illust. under Invagination. In a more general sense, an ideal stage in embryonic development. See Gastraea

Gastrula(adj)

of or pertaining to a gastrula

Gastrula

The developmental stage that follows BLASTULA. It is characterized by the morphogenetic cell movements including invagination, ingression, and involution. Gastrulation begins with the formation of the PRIMITIVE STREAK, and ends with the formation of three GERM LAYERS, the body plan of the mature organism.