Membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional
English: yolk sac, vitelline sac, umbilical vesicle, vesicula umbilicus
umbilical vesicle, vesicula umbilicus, vitelline sac, yolk sac
English: yolk sac, vitelline sac, umbilical vesicle, vesicula umbilicus