cilium


cilium
/sil"ee euhm/, n.
sing. of cilia.
[ < L]

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Short, eyelashlike filament that is numerous on tissue cells of most animals.

Capable of beating in unison, cilia perform a variety of functions, including providing the means of locomotion for some protozoans, moving mammalian ova (eggs) through oviducts, generating water currents to carry food and oxygen past the gills of clams, and cleaning debris from mammalian respiratory systems. Like a flagellum, a cilium has a central core consisting of two central microtubules surrounded by an outer ring of nine double fibres. Ciliary outgrowth is controlled by the basal body, located just inside the cell surface at the base of the cilium. Beneath the surface of some cells is a network of microtubular bundles that may coordinate ciliary beating.

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 short eyelashlike filament that is numerous on tissue cells of most animals and provides the means for locomotion of protozoans of the phylum Ciliophora. Cilia may be fused in short transverse rows to form membranelles or in tufts to form cirri. Capable of beating in unison, cilia move mammalian ova through oviducts, generate water currents to carry food and oxygen past the gills of clams, carry food through the digestive systems of snails, circulate cerebrospinal fluid of animals, and clean debris from the respiratory systems of mammals. In modified form, cilia trigger the discharge of stinging devices in jellyfish and give rise to the light-sensitive rods of the mammalian retina and the odour-detecting units of olfactory neurons.

      A cilium, like a flagellum (q.v.), is composed of a central core (the axoneme), which contains two central microtubules that are surrounded by an outer ring of nine pairs of microtubules. The outer ring of microtubules is surrounded by a membrane that is continuous with the cell membrane; ciliary outgrowth is controlled by the basal body that is located just inside the cell surface at the base of the cilium. Beneath the surface of some cells there is a network of fibrous rootlets or microtubular bundles that may provide support for the epithelium or coordinate ciliary beating.

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Universalium. 2010.

Look at other dictionaries:

  • Cilium — Cil i*um, n. [L., eyelid.] See {Cilia}. [1913 Webster] …   The Collaborative International Dictionary of English

  • cilium — cilium. См. ресничка. (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.

  • CILIUM — Africae propriae urbs. Antonin. Item civitas antiqua Apuliae Peucetiae …   Hofmann J. Lexicon universale

  • cilium — ► NOUN (pl. cilia) 1) Biology a microscopic hair like vibrating structure, occurring on the surface of certain cells. 2) Anatomy an eyelash. ORIGIN Latin …   English terms dictionary

  • cilium — [sil′ē əm] n. sing. of CILIA …   English World dictionary

  • Cilium — Not to be confused with Psyllium. Cilium SEM micrograph of the cilia projecting from respiratory epithelium in the lungs Code TH …   Wikipedia

  • Cilium — Darstellung von Zilien unter dem Elektronenmikroskop. Sichtbar ist die 9x2+2 Struktur. Als Zilie oder Cilium (lat., n.; auch Kinozilie, Flimmerhärchen, Wimper) bezeichnet man 5–10 µm lange und 250 nm dicke Zytoplasmafortsätze von eukaryotischen… …   Deutsch Wikipedia

  • Cilium — Cilia Cil i*a, n. pl. {Cilium}, the sing., is rarely used. [L. cilium eyelid.] 1. (Anat.) The eyelashes. [1913 Webster] 2. (Biol.) Small, generally microscopic, vibrating appendages lining certain organs, as the air passages of the higher animals …   The Collaborative International Dictionary of English

  • cilium — (= cilia (plural) ) Motile appendage of eukaryotic cells that contains an axoneme, a bundle of microtubules arranged in a characteristic fashion with nine outer doublets and a central pair (‘9+2’ arrangement). Active sliding of doublets relative… …   Dictionary of molecular biology

  • Cilium — A fine hairlike projection from a cell such as those in the respiratory tract. Cilia can help to sweep away fluids and particles. Some single celled organisms use the rhythmical motion of cilia for locomotion. Cilium is Latin. It referred to the… …   Medical dictionary


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