allantois

/uh-lan-toh-is, -tois/US // əˈlæn toʊ ɪs, -tɔɪs //UK // (ˌælənˈtəʊɪs, əˈlæntɔɪs) //

尿囊素,尿毒症,尿囊炎,尿囊菌

Definitions

n.名词 noun

1
Embryology, Zoology.
- : a vascular, extraembryonic membrane of birds, reptiles, and certain mammals that develops as a sac or diverticulum from the ventral wall of the hindgut.

The cavity of the allantois, if developed, vanishes completely.
This bag is called the allantois, and serves as a sort of lung for the developing chick.
It draws its oxygen and throws off its wastes through the instrumentality of the allantois, which covers it over.
The blood vessels of the allantois take in oxygen and give out carbon dioxide through the porous shell.
The allantois of the chick now gains a new development and an altered function.