cotyledon

cotyledon
1. See maternal c., fetal c.. 2. In plants, a seed leaf, the first leaf to grow from a seed. 3. A placental unit. See maternal c.. [G. kotyledon, any cup-shaped hollow]
- fetal c. a unit of the fetal placenta supplied by the vessels of a stem villus; several such cotyledons may occur between two placental septa; traditionally called embryologists' c..
- maternal c. a unit of the placenta made up of trophoblastic cells, fibrous tissue, and abundant blood vessel s, which is visible grossly on the maternal surface as an irregularly shaped lobe circumscribed by a deep cleft and made up of a stem villus with numerous branching free villi and anchoring villi; placental vessels in the chorionic plate supply the stem villus and its branches, allowing gas and metabolite exchange across the trophoblastic layer with maternal blood in the intervillous space; traditionally called clinicians' c..

* * *

cot·y·le·don .kät-əl-'ēd-ən n
1) a lobule of a mammalian placenta
2) the first leaf or one of the first pair or whorl of leaves developed by the embryo of a seed plant or of some lower plants (as ferns)
cot·y·le·don·ary -'ēd-ən-.er-ē adj

* * *

n.
any of the major convex subdivisions of the mature placenta. Each cotyledon contains a major branch of the umbilical blood vessels, which branch further into the numerous villi that make up the surface of the cotyledon.

* * *

Cot·y·le·don (kot″ə-leґdən) a genus of herbaceous plants found in southern Africa; several species contain cotyledontoxin.

Medical dictionary. 2011.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Cotyledon — Saltar a navegación, búsqueda ? Cotyledon Cotyledon tomentosa ssp. ladysmithensis …   Wikipedia Español

  • cotylédon — [ kɔtiledɔ̃ ] n. m. • 1534; cotillidones 1314; gr. kotulêdon « creux, cavité » → cotyle 1 ♦ Embryol. Chacun des segments polygonaux, délimités par des cloisons, à la surface utérine du placenta humain ou animal. 2 ♦ (XVIIIe) Bot. Feuille… …   Encyclopédie Universelle

  • Cotyledon — Cotylédon Les deux cotylédons d une graine de Jacaranda mimosifolia en phase de germination Les cotylédons (scientifiquement nommés feuilles cotylédonaires) sont les feuilles primordiales constitutives de la graine. Le terme vient du grec… …   Wikipédia en Français

  • cotyledon — from 1540s, in various sense, from L. cotyledon pennywort, navelwort, from Gk. kotyledon cup shaped cavity, from kotyle hollow thing, small vessel, also the name of a small liquid measure (nearly a half pint); of uncertain origin. Botanical sense …   Etymology dictionary

  • Cotyledon — Cot y*le don (k?t ? l? d?n), n. [Gr.??? a cupshaped hollow, fr. ???. See {Cotyle}.] 1. (Anat.) One of the patches of villi found in some forms of placenta. [1913 Webster] 2. (Bot.) A leaf borne by the caulicle or radicle of an embryo; a seed leaf …   The Collaborative International Dictionary of English

  • Cotylēdon — (C. L.), Pflanzengattung aus der Familie der Crassulaceae Crassuleae Diplostemones Umbiliceae, 5. Ordn. 6. Kl.L. Arten: C orbiculata, mit flachen, spatelförmigen, fleischigen, mehligen, gegenüberstehenden Blättern, rispenständigen, rothen Blüthen …   Pierer's Universal-Lexikon

  • Cotylĕdon — Dec. (Nabelkraut), Gattung der Krassulazeen, Kräuter oder Halbsträucher von sehr verschiedener Tracht, mit gegenständigen oder abwechselnden, einfachen, oft rosettenförmig gehäuften, fleischig saftigen Blättern, purpurroten oder hochgelben Blüten …   Meyers Großes Konversations-Lexikon

  • Cotyledon — Cotylĕdon L., Nabelkraut, Pflanzengattg. der Krassulazeen, schönblühende Kapsträucher; bei uns Zierpflanzen …   Kleines Konversations-Lexikon

  • Cotyledon —   [griechisch kotylēdo̅n »Vertiefung«, »Saugwarze«], Kotyledon, Botanik: Gattung der Dickblattgewächse mit etwa 50 meist in Südafrika beheimateten Arten von strauchiger oder stammsukkulenter Wuchsform; zum Teil Zimmerpflanzen.   …   Universal-Lexikon

  • cotylédon — COTYLÉDON, ou Nomeril de Vénus. s. m. Plante qui croît sur les rochers et sur les vieilles murailles. On lui attribue les mêmes vertus qu à la Rhubarbe …   Dictionnaire de l'Académie Française 1798

  • cotyledon — ► NOUN ▪ an embryonic leaf, the first leaf to grow from a germinating seed. ORIGIN Greek kotul d n cup shaped cavity …   English terms dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”