yolk-sac

英 ['jəʊks'æk] 美 ['jəʊks'æk]

• 卵黄囊

英英释义

名词 yolk sac:

1. membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional

2. membranous structure enclosing the yolk of eggs in birds, reptiles, marsupials, and some fishes; circulates nutrients to the developing embryo