The mesectodermal cell layer covering the blastocyst that erodes the uterine mucosa and through which the embryo receives nourishment from the mother; the cells do not enter into the formation of the embryo itself, but contribute to the formation of the placenta. The t. develops processes that later receive a core of vascular mesoderm and are then known as the chorionic villi; the t. soon becomes two-layered, differentiating into the syncytiotrophoblast, an outer layer consisting of a multinucleated protoplasmic mass (syncytium), and the cytotrophoblast, the inner layer next to the mesoderm in which the cells retain their membranes. SYN: chorionic ectoderm. [tropho- + G. blastos, germ]

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tro·pho·blast 'trō-fə-.blast n the outer layer of the mammalian blastocyst that supplies nutrition to the embryo, facilitates implantation by eroding away the tissues of the uterus with which it comes in contact allowing the blastocyst to sink into the cavity formed in the uterine wall, and differentiates into the extraembryonic membranes surrounding the embryo called also trophoderm
tro·pho·blas·tic .trō-fə-'blas-tik adj

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the tissue that forms the wall of the blastocyst. At implantation it forms two layers, an inner cellular layer (cytotrophoblast) and an outer syncytial layer (plasmoditrophoblast), which forms the outermost layer of the placenta and attains direct contact with the maternal bloodstream.
Trophoblast sampling was the name originally given to the technique now known as chorionic villus sampling.

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tro·pho·blast (troґfo-blast) [tropho- + -blast] a layer of extraembryonic ectodermal tissue on the outside of the blastocyst. It attaches the blastocyst to the endometrium of the uterine wall and supplies nutrition to the embryo. From it are derived the chorion and amnion. The inner cellular layer of the trophoblast covering a chorionic villus is called cytotrophoblast and its outer syncytial layer syncytiotrophoblast. The mesoblast, once thought to be trophoblastic, is now traced in primates to the caudal end of the primitive streak. trophoblastic adj

Medical dictionary. 2011.

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Look at other dictionaries:

  • Trophoblast — Blastocyst with an inner cell mass and trophoblast …   Wikipedia

  • trophoblast — trophoblast. См. трофобласт. (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.

  • Trophoblast — Trophoblast, in der ⇒ Morula und der ⇒ Blastocyste der Säuger die äußere, extraembryonale Zellschicht, die der Festheftung des Keims in der Gebärmutterwand sowie der Ernährung dient und später das ⇒ Chorion bildet …   Deutsch wörterbuch der biologie

  • trophoblast — [träf′ə blast΄] n. [ TROPHO + BLAST] a layer of nutritive ectoderm outside the blastoderm, by which the fertilized ovum is attached to the uterine wall and the developing embryo receives its nourishment trophoblastic adj …   English World dictionary

  • Trophoblast — schematischer Aufbau der Blastozyste Das Trophoblast ist die äußere Zellschicht einer Blastozyste und verbindet diese mit der Gebärmutterwand. Es bildet sich am 5. bis 12. Tag nach der Befruchtung aus Blastomere, weicht mittels Enzymen die… …   Deutsch Wikipedia

  • Trophoblast — Tro|pho|blạst 〈m. 16〉 äußere Schicht der Keimblase, über die die Ernährung des Embryos erfolgt [<grch. trophe „Nahrung“ + blastos „Keim, Spross“] * * * Trophoblạst   [zu griechisch blastós »Blatt«, »Spross«] der, en/ en, Blastodẹrm,… …   Universal-Lexikon

  • trophoblast — noun Etymology: International Scientific Vocabulary Date: 1889 the outer layer of the mammalian blastocyst that supplies nutrition to the embryo and facilitates implantation • trophoblastic adjective …   New Collegiate Dictionary

  • trophoblast — Extra embryonic layer of epithelium that forms around the mammalian blastocyst, and attaches the embryo to the uterus wall. Forms the outer layer of the chorion, and together with maternal tissue will form the placenta …   Dictionary of molecular biology

  • trophoblast — trophoblastic, adj. /trof euh blast , troh feuh /, n. Embryol. the layer of extraembryonic ectoderm that chiefly nourishes the embryo or develops into fetal membranes with nutritive functions. [1885 90; TROPHO + BLAST] * * * …   Universalium

  • trophoblast — noun /ˈtɹɒfə(ʊ)blɑːst/ The membrane of cells that forms the wall of a blastocyst during early pregnancy, providing nutrients to the embryo and later developing into part of the placenta …   Wiktionary

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