amnion


amnion
/am"nee euhn/, n., pl. amnions, amnia /-nee euh/.
1. Anat., Zool. the innermost of the embryonic or fetal membranes of reptiles, birds, and mammals; the sac in which the embryo is suspended.
2. Zool. a similar membrane of insects and other invertebrates.
[1660-70; < Gk, equiv. to amn(ós) lamb (see YEAN) + -ion dim. suffix]

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      in reptiles, birds, and mammals, a membrane forming a fluid-filled cavity (the amniotic sac) that encloses the embryo. The amniotic sac and the fluid it contains are sometimes referred to as the bag of waters.

      In development, the amnion arises by a folding of a mass of extra-embryonic tissue called the somatopleure. Lined with ectoderm and covered with mesoderm (both are germ layers), the amnion contains a thin, transparent fluid in which the embryo is suspended, thus providing a cushion against mechanical injury. The amnion also provides protection against fluid loss from the embryo itself and against tissue adhesions.

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Universalium. 2010.

Look at other dictionaries:

  • Amnĭon — Amnĭon, 1) (gr. Ant.), Opferschale zum Auffangen des Blutes; 2) (Amnium), Schafhäutchen, die innerste Haut der Eihüllen (s.d.), welche den Fötus der Säugethiere u. Menschen umschließen; sie scheidet eine Flüssigkeit (Amniumwasser, Amnii liquor,… …   Pierer's Universal-Lexikon

  • amnion — (n.) 1660s, Modern Latin, from Gk. amnion membrane around a fetus, said to be originally bowl in which the blood of victims was caught [Liddell & Scott], which is variously said to be of unknown origin, from ame bucket, or a dim. of amnos lamb …   Etymology dictionary

  • amnion — amnìōn m <G amnióna> DEFINICIJA fiziol. unutrašnjost embrijske ovojnice; poput mjehura obavija embrij i sadrži amnionsku tekućinu (plodovu vodu); amnij ETIMOLOGIJA nlat. ← grč. amníon: posteljica ≃ amnós: janje …   Hrvatski jezični portal

  • Amnion — Am ni*on, n. [Gr. ? the membrane round the fetus, dim. of ? lamb.] (Anat.) A thin membrane surrounding the embryos of mammals, birds, and reptiles. [1913 Webster] …   The Collaborative International Dictionary of English

  • amnion — amnion. См. амнион. (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.

  • Amnĭon — Amnĭon, s. Embryonalhüllen …   Meyers Großes Konversations-Lexikon

  • Amnion — Amnĭon (grch.), Schafhaut, die innerste Eihaut, die den Embryo der höhern Wirbeltiere (Reptilien. Vögel und Säugetiere, der Amniōten) umgibt, enthält eine eiweißhaltige Flüssigkeit (Amnionwasser, Fruchtwasser), in welcher der Fötus, vor Druck und …   Kleines Konversations-Lexikon

  • Amnion — (Schafhäutchen) heißt die innerste von den häutigen Hüllen, welche im menschlichen und thierischen Eie den Embryo umgeben. Sie ist dünn, dabei aber fest und schließt eine eigene Flüssigkeit, das Fruchtwasser in sich, in dem der Embryo gleichsam… …   Herders Conversations-Lexikon

  • Amnion — ⇒ Embryonalhüllen …   Deutsch wörterbuch der biologie

  • amnion — [am′nē ən, am′nēän΄] n. pl. amnions or amnia [am′nēə] [Gr, dim. of amnos, lamb < IE * agwhnos > YEAN, L agnus] 1. the innermost membrane of the sac enclosing the embryo of a mammal, reptile, or bird: it is filled with a watery fluid… …   English World dictionary

  • Amnion — Infobox Anatomy Name = Amnion Latin = GraySubject = 12 GrayPage = 56 Caption = Surface view of embryo of Hylobates concolor. Caption2 = Human fetus, enclosed in the amnion. System = MeshName = Amnion MeshNumber = A10.615.284.277 : For the alien… …   Wikipedia


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