Ectoderm

One of the three primary germ cell layers (the other two being the mesoderm and endoderm) that make up the very early embryo. The ectoderm is the outermost of the three layers. It differentiates to give rise to many important tissues and structures including the outer layer of the skin and its appendages (the sweat glands, hair, and nails), the teeth, the lens of the eye, parts of the inner ear, the nerves, brain, and spinal cord. This much is classic human embryology. Stem cell research, however, has shown that some cells within ectodermal structures retain their ability to differentiate into other tissues. For example, some cells in brain (ectoderm) can become bone marrow (mesoderm).
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The outer layer of cells in the embryo, after establishment of the three primary germ layers (e., mesoderm, endoderm), the germ layer in contact with the amnionic cavity. SYN: ectoblast (1). [ecto- + G. derma, skin]
- amnionic e. inner layer of the amnion continuous with body e..
- epithelial e. that part of the e. separating from the neuroectoderm at about the fourth week of embryonic life; the epidermis and its specialized derivatives develop from it. SYN: superficial e..
- extraembryonic e. derivative of epiblast outside the embryo's body.
- superficial e. SYN: epithelial e..

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ec·to·derm 'ek-tə-.dərm n
1) the outermost of the three primary germ layers of an embryo
2) a tissue (as neural tissue) derived from ectoderm
ec·to·der·mal .ek-tə-'dər-məl adj

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n.
the outer of the three germ layer of the early embryo. It gives rise to the nervous system and sense organs, the teeth and lining of the mouth, and to the epidermis and its associated structures (hair, nails, etc.).
ectodermal adj.

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ec·to·derm (ekґto-dərm) [ecto- + derm] the outermost layer of cells of the three primary germ layers of the embryo. From it are developed the epidermis and the epidermal tissues, such as the nails, hair, enamel of teeth, and glands of the skin, the nervous system, the external sense organs such as the ear and eye, and the mucous membrane of the mouth and anus. Cf. endoderm and mesoderm. ectodermal, ectodermic adj

Medical dictionary. 2011.

Look at other dictionaries:

  • ectoderm — ECTODÉRM, ectoderme, s.n. Învelişul extern al embrionului, din care provin tegumentele şi sistemul nervos. ♦ Tegumentul extern al celenteratelor. – Din fr. ectoderme. Trimis de LauraGellner, 10.06.2004. Sursa: DEX 98  ECTODÉRM s. (biol.)… …   Dicționar Român

  • Ectoderm — Ec to*derm, n. [Ecto + derm.] (Biol.) (a) The outer layer of the blastoderm; epiblast. (b) The external skin or outer layer of an animal or plant, this being formed in an animal from the epiblast. See Illust. of {Blastoderm} …   The Collaborative International Dictionary of English

  • ectoderm — ectoderm. См. эктодерма. (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.

  • ectoderm — 1861, from ECTO (Cf. ecto ) + DERM (Cf. derm). Coined by Prussian embryologist Robert Remak (1815 1865) …   Etymology dictionary

  • ectoderm — [ek′tō dʉrm΄, ek′tədʉrm΄] n. [ ECTO + DERM] 1. the outer layer of cells of an animal embryo, from which the nervous system, skin, hair, teeth, etc. are developed 2. the layer or layers of cells composing the skin, nervous system, etc. in all… …   English World dictionary

  • Ectoderm — Infobox Embryology Name = PAGENAME Latin = GraySubject = 6 GrayPage = 48 Caption = Organs derived from ectoderm. Caption2 = Section through embryonic disk of Vespertilio murinus. System = CarnegieStage = Days = 16 Precursor = GivesRiseTo =… …   Wikipedia

  • ectoderm — ectodermal, ectodermic, adj. ectodermoidal /ek toh deuhr moyd l/, adj. /ek teuh derrm /, n. Embryol. the outer germ layer in the embryo of a metazoan. Also called ectoblast. [1860 65; ECTO + DERM] * * * ▪ anatomy       the outermost of the three… …   Universalium

  • ectoderm — The outer of the three germ layers of the embryo (the other two being mesoderm and endoderm). Ectoderm gives rise to epidermis and neural tissue …   Dictionary of molecular biology

  • ectoderm —   n. outermost membrane and tissue.    ♦ ectodermal,    ♦ ectodermic, a.    ♦ ectodermosis,   n. disease of the ectoderm …   Dictionary of difficult words

  • ectoderm — noun Etymology: International Scientific Vocabulary Date: 1859 1. the outer cellular membrane of a diploblastic animal (as a jellyfish) 2. a. the outermost of the three primary germ layers of an embryo that is the source of …   New Collegiate Dictionary

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