A hollow, cylindrical cytoplasmic element, 20–27 nm in diameter and of variable length, that occurs widely in the cytoskeleton, cilia, and flagella of cells; microtubules play a role in the maintenance of cell shape and increase in number during mitosis and meiosis, where they are related to movement of the chromosomes by the nuclear spindle.
- subpellicular m. a m. lying beneath the unit membrane (pellicle) of many protozoans, often as a palisade of longitudinally arranged fibrils connected by fine lateral bridges that support the external cell form; in certain sporozoan stages a fixed number of microtubules are found, extending longitudinally from the polar ring. SYN: subpellicular fibril.

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mi·cro·tu·bule .mī-krō-'t(y)ü-(.)byü(ə)l n any of the minute tubules in eukaryotic cytoplasm that are composed of the protein tubulin and form an important component of the cytoskeleton, mitotic spindle, cilia, and flagella
mi·cro·tu·bu·lar -byə-lər adj

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mi·cro·tu·bule (mi″kro-tooґbūl) a tubular cytoplasmic structure, 25 nm in diameter and of variable length, composed of α- and β-tubulin dimers, whose orientation imparts polarity; microtubules are involved in maintenance of cell shape and in the movements of organelles and inclusions and form the spindle fibers of mitosis. In cilia and flagella, they are constantly arranged with two single microtubules in the center and nine pairs of doublets arrayed around the central two.

Microtubules in a 9 + 2 array in a cross-section of the axoneme of a cilium.

Medical dictionary. 2011.

Look at other dictionaries:

  • microtubule — [ mikrotybyl ] n. m. • av. 1972; en angl. 1963; de micro et tubule ♦ Biol. Composant du cytosquelette, formé par polymérisation de la tubuline. ● microtubule nom masculin Fine structure cytoplasmique cylindrique, constituant des centrioles, des… …   Encyclopédie Universelle

  • microtubule — microtubule. См. микротрубочка. (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.

  • microtubule —  Microtubule  Микротрубочка   Полая цилиндрическая трубочка, используемая для транспортировки веществ внутри клетки.    Строение микротрубочки, в которой 13 тубулиновых α /β гетеродимеров уложены по окружности полого цилиндра. Внешний диаметр… …   Толковый англо-русский словарь по нанотехнологии. - М.

  • microtubule — [mī΄krō to͞o′byo͞ol΄] n. any of a number of small, hollow filaments, composed of long strands of tubulins, that are found in animal or plant cells and are associated esp. with cell structure and movement and with mitosis …   English World dictionary

  • Microtubule — Space filling model of a microtubule segment derived from cryo electron microscopy. The protofilaments are seen running along the axis of the segment. The microtubule (+) end is towards the top of the image.[1] Microtubules are a component of the …   Wikipedia

  • Microtubule — Les microtubules (MT) sont des fibres constitutives du cytosquelette, au même titre que les microfilaments d actine et que les filaments intermédiaires. Ils ont un diamètre d environ 25 nm et une longueur variable du fait de leur dynamique (liée… …   Wikipédia en Français

  • microtubule — noun Date: 1961 any of the minute tubules in eukaryotic cytoplasm that are composed of the protein tubulin and form an important component of the cytoskeleton, mitotic spindle, cilia, and flagella • microtubular adjective …   New Collegiate Dictionary

  • microtubule — Cytoplasmic tubule, 25nm outside diameter with a 5nm thick wall. Made of tubulin heterodimers packed in a three start helix (or of 13 protofilaments looked at another way), and associated with various other proteins (MAPs, dynein, kinesin).… …   Dictionary of molecular biology

  • microtubule — /muy kroh tooh byoohl, tyooh /, n. Cell Biol. a hollow cylindrical structure in the cytoplasm of most cells, involved in intracellular shape and transport. See diag. under cell. [1960 65; MICRO + TUBULE] * * * Tubular structure enclosed by a… …   Universalium

  • microtubule — noun small tubes made of protein and found in cells and is part of the cytoskeleton …   Wiktionary

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