allantoic duct
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Cyst — A closed sac or capsule, usually filled with fluid or semisolid material. * * * 1. A bladder. 2. An abnormal sac containing gas, fluid, or a semisolid material, with a membranous lining. SEE ALSO: pseudocyst. [G. kystis, bladder] adventitious c.… … Medical dictionary
Diverticulum — 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… … Medical dictionary
Urachus — A canal connecting the bladder of the fetus with the allantois, a structure that contributes to the formation of the umbilical cord. The lumen (inside) of the urachus is normally obliterated during embryonic development, transforming the urachus… … Medical dictionary
stalk — A narrowed connection with a structure or organ. allantoic s. the narrow connection between the intraembryonic portion of the allantois and the extraembryonic allantoic vesicle … 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
Cloaca (embryology) — For other uses, see Cloaca. Cloaca (embryology) Tail end of human embryo thirty two to thirty three days old. Cloaca is visible at center left. The endodermal cloaca is labeled with green, while the ectodermal cloaca is seen as a colorless crest… … Wikipedia
fold — 1. A ridge or margin apparently formed by the doubling back of a lamina. SYN: plica. 2. In the embryo, a transient elevation or reduplication of tissue in the form of a lamina … Medical dictionary
sac — 1. A pouch or bursa. SYN: saccus [TA]. SEE ALSO: sacculus. 2. An encysted abscess at the root of a tooth. 3. The capsule of a tumor, or envelope of a cyst. [L. saccus, a … Medical dictionary
Chorion — For the chorion in invertebrate eggs, see Chorion (egg). Chorion Diagram showing earliest observed stage of human embryo … Wikipedia
