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