Search Result:yolk sac
Overview of noun yolk_sac
The noun yolk sac has 2 senses
- yolk sac, vitelline sac, umbilical vesicle, vesicula umbilicus -- (membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional)
- yolk sac -- (membranous structure enclosing the yolk of eggs in birds, reptiles, marsupials, and some fishes; circulates nutrients to the developing embryo)