gastrula

/gas-troo-luh/US // ˈgæs trʊ lə //UK // (ˈɡæstrʊlə) //

胃肠道,胃管,胃肠,胃镜

Definitions

n.名词 noun

1
plural gas·tru·las, gas·tru·lae [gas-troo-lee]. /ˈgæs trʊˌli/. Embryology.
- : a metazoan embryo in an early state of germ layer formation following the blastula stage, consisting of a cuplike body of two layers of cells, the ectoderm and endoderm, enclosing a central cavity, or archenteron, that opens to the outside by the blastopore: in most animals progressing to the formation of a third cell layer, the mesoderm.

A view of the gastrula stage after the larva has become fixed is given in fig. 2.
At the same time they become clearer and permit a view of the interior of the gastrula.
This gastrula is the simplest form of the "person," and the two germinal layers are its sole organs.
In the further development of the various tissue-forming animals from the gastrula we have to distinguish two principal groups.
The two-layered young stage of higher creatures, when it has a free-swimming existence, is called a Gastrula (Fig. 6).