yolk sac
1yolk sac — n. Zool. 1. a saclike vascular membrane containing yolk, an outgrowth from the ventral surface of very yolky vertebrate embryos, as those of fishes, birds, or reptiles, that supplies nourishment to the embryo 2. a homologous organ in most… …
2yolk sac — yolk′ sac n. dvl an extraembryonic membrane that encloses the yolk of eggs • Etymology: 1860–65 …
3yolk sac — yolk sac. См. желточный мешок. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …
4Yolk sac — Not all yolk has to do with birds’ eggs. Human embryos have a yolk sac, a membrane outside the embryo but connected by a tube (the yolk stalk) though the umbilical opening to the embryo’s midgut. The yolk sac serves as an early site for …
5Yolk sac — Infobox Embryology Name = Yolk sac Latin = GraySubject = 11 GrayPage = 54 Caption = Human embryo of 2.6 mm. Caption2 = Human embryo from thirty one to thirty four days System = CarnegieStage = 5b Days = 9 Precursor = endoderm GivesRiseTo =… …
6yolk sac — noun 1. membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional • Syn: ↑vitelline sac, ↑umbilical vesicle, ↑vesicula umbilicus • Hypernyms: ↑sac 2. membranous structure enclosing the… …
7yolk sac — thin membrane which surrounds the yolk of an egg and supplies nutrients to the embryo (in mammals, the yolk sac ceases to function when the placenta forms) …
8yolk sac tumor — a malignant germ cell tumor of children that represents a proliferation of both yolk sac endoderm and extraembryonic mesenchyme. It is characterized by a labyrinthine glandular pattern with a papillary projection into a sinuslike space;… …
9yolk-sac larva — a fish larva which has already hatched from the egg but has not started feeding yet and still absorbs the yolk in the ventrally attached yolk sac. At the end of this stage in development, the yolk and oil globule(s) have been used up, the major… …
10yolk-sac placenta — the yolk sac helps in formation of a placenta which allows a connection of the embryo to the mother for nourishment …