gastrula


gastrula
The embryo in the stage of development following the blastula; in lower forms with minimal yolk, it is a simple double-layered structure consisting of ectoderm and endoderm enclosing the archenteron, which opens to the outside by way of the blastopore; in forms with considerable yolk, the configuration of the g. is greatly modified owing to the persistence of the yolk throughout the gastrulation process. SYN: invaginate planula. [Mod. L. dim. of G. gaster, belly]

* * *

gas·tru·la 'gas-trə-lə n, pl -las or -lae -.lē, -.lī an early metazoan embryo in which the ectoderm, mesoderm, and endoderm are established either by invagination of the blastula (as in fish and amphibians) to form a multilayered cellular cup with a blastopore opening into the archenteron or (as in reptiles, birds, and mammals) by differentiation of the upper layer of the blastodisc into the ectoderm and the lower layer into the endoderm and by the inward migration of cells through the primitive streak to form the mesoderm compare MORULA
gas·tru·lar -lər adj

* * *

n.
an early stage in the development of many animal embryos. It consists of a double-layered ball of cells formed by invagination and movement of cells in the preceding single-layered stage (blastula) in the process of gastrulation. It contains a central cavity, the archenteron, which opens through the blastopore to the outside. True gastrulation only occurs in the embryos of amphibians and certain fish, but a similar process occurs in the embryonic disc in other vertebrates, including humans.

* * *

gas·tru·la (gasґtroo-lə) the early embryo in the stage following the blastula or blastocyst. The simplest type consists of two layers, the ectoderm and the endoderm, and of two cavities, one lying between the ectoderm and the endoderm; the other (the archenteron) is formed by invagination so as to lie within the endoderm and having an opening (the blastopore). In human embryos the gastrula stage occurs during the third week, as the embryonic disc becomes trilaminar, establishing the ectoderm, mesoderm, and endoderm from the epiblast.

Medical dictionary. 2011.

Look at other dictionaries:

  • gastrula — [ gastryla ] n. f. • 1874; lat. sav. (1872, Haeckel), dimin. de gastra « vase », du gr. gastêr→ gastéro ♦ Embryol. Stade du développement embryonnaire caractérisé par la présence d une cavité endodermique primitive. ● gastrula nom féminin (latin… …   Encyclopédie Universelle

  • gastrulă — GASTRÚLĂ s.f. (biol.) Stadiu în dezvoltarea embrionului la animalele pluricelulare. – Din fr. gastrula. Trimis de gall, 13.09.2007. Sursa: DEX 98  gastrúlă s. f., g. d. art. gastrúlei Trimis de siveco, 10.08.2004. Sursa: Dicţionar ortografic … …   Dicționar Român

  • gástrula — f. embriol. Fase del desarrollo del embrión posterior a la blástula; corresponde al período comprendido entre el 15 y 18 después de la fecundación, en la que se delimitan las tres hojas embrionarias: ectodermo, mesodermo, endodermo. También se… …   Diccionario médico

  • Gastrula — Gas tru*la, n.; pl. {Gastrul[ae]}[NL., dim. fr. Gr. ? the stomach.] (Biol.) An embryonic form having its origin in the invagination or pushing in of the wall of the planula or blastula (the blastosphere) on one side, thus giving rise to a double… …   The Collaborative International Dictionary of English

  • gastrula — gastrula. См. гаструла. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Gastrŭla — (Becherkeim, Becherlarve), ganz junge Larve und häufige Embryonalform vieler wirbellosen Tiere. S. Entwickelungsgeschichte, S. 845 …   Meyers Großes Konversations-Lexikon

  • Gastrula — Gastrŭla, Darmlarve, nach Haeckel die Entwicklungsform des tierischen Eies, in der die den Keim bildenden Zellen eine Schale mit doppelter, eine Höhlung (Keimhöhle, Blastocölom) umschließender Wand darstellen, entstanden aus dem durch Klüftung… …   Kleines Konversations-Lexikon

  • Gastrula — Gastrula, Becherkeim, ein Embryonalstadium der Metazoen; entsteht bei der ⇒ Gastrulation aus der ⇒ Blastula. Die typische G. ist zweischichtig und becherförmig, besteht aus äußerem (Ektoderm) und innerem Keimblatt (Entoderm) und umschließt eine… …   Deutsch wörterbuch der biologie

  • gastrula — 1877, Mod.L., from Gk. gaster (gen. gastros) + L. ula, dim. suffix. Related: Gastrulation …   Etymology dictionary

  • gástrula — s. f. 1. Cavidade resultante da invaginação de metade da blástula na outra metade. 2. Forma larval inicial, comum a todos os metazoários …   Dicionário da Língua Portuguesa

  • gastrula — gȁstrula ž DEFINICIJA biol. treći stadij embrionalnog razvitka višestaničnih bića (poslije blastule), sastoji se od ektoderma i endoderma, oni zatvaraju središnju šupljinu koja se otvara prema vani pomoću blastopora ETIMOLOGIJA nlat. ≃ grč.… …   Hrvatski jezični portal