yolk sac endoderm
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yolk 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;… … Medical dictionary
Yolk 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 =… … Wikipedia
Yolk 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 … Medical dictionary
yolk sac — vitelline sac the membranous sac, composed of mesoderm lined with endoderm, that lies ventral to the embryo. It is one of the extraembryonic membranes. Its initially wide communication with the future gut is later reduced to a narrow duct passing … The new mediacal dictionary
yolk sac — One of the set of extra embryonic membranes, growing out from the gut over the yolk surface, in birds formed from the splanchnopleure, an outer layer of splanchnic mesoderm and an inner layer of endoderm … Dictionary of molecular biology
primitive endoderm — primordial endoderm the primary internal layer of the gastrula that becomes both gut and yolk sac … Medical dictionary
lecithoblast — One of the cells proliferating to form the yolk sac endoderm. [G. lekithos, egg yolk, + blastos, germ] * * * lec·i·tho·blast (lesґĭ tho blast″) [lecitho + blast] the primordial endoderm of a two layered blastodisc … Medical dictionary
animal development — Introduction the processes that lead eventually to the formation of a new animal starting from cells derived from one or more parent individuals. Development thus occurs following the process by which a new generation of organisms is produced by … Universalium
human embryology — ▪ biology Introduction the process encompassing the period from the formation of an embryo, through the development of a fetus, to birth. The human body, like that of most animals, develops from a single cell produced by the union of… … Universalium
Human embryogenesis — is the process of cell division and cellular differentiation of the human embryo during early prenatal development. It spans from the moment of fertilization to the end of the 8th week of gestational age, whereafter the embryo is called a fetus.… … Wikipedia
