extraembryonic endoderm
21Cleavage (embryo) — In embryology, cleavage is the division of cells in the early embryo. The zygotes of many species undergo rapid cell cycles with no significant growth, producing a cluster of cells the same size as the original zygote. The different cells derived …
22Germ line development — The cells that give rise to the gametes are often set aside during cleavage. During development, these cells will differientate into primordial germ cells, migrate to the location of the gonad, and form the germ line of the animal. Creation of… …
23Induced pluripotent stem cell — Induced pluripotent stem cells, commonly abbreviated as iPS cells or iPSCs, are a type of pluripotent stem cell artificially derived from a non pluripotent cell, typically an adult somatic cell, by inducing a forced expression of certain genes.… …
24Diverticulum — A small bulging sac pushing outward from the colon wall is a diverticulum. As a person ages, pressure within the large intestine (colon) causes pockets of tissue (sacs) that push out from the colon walls. The plural is diverticula. Diverticula… …
25yolk 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;… …
26yolk 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 …
