Noun:
-
membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional
- The yolk sac is gradually vascularized.
卵黄囊逐渐被血管化了。
- The gonads form from a group of large granulated yolk sac cells which invacle the germinal ridges.
性腺是由一群大的颗粒的卵黄囊细胞入缀生殖峭而形成。
