yolk sac

Other Definitions
yolk sac (enc)

Noun	1.	yolk sac - membranous structure that functions as the circulatory system in mammal embryos until the heart becomes functional umbilical vesicle, vesicula umbilicus, vitelline sac sac - a structure resembling a bag in an animal
	2.	yolk sac - membranous structure enclosing the yolk of eggs in birds reptiles marsupials and some fishes; circulates nutrients to the developing embryo sac - a structure resembling a bag in an animal

Word Browser