callus


callus
/kal"euhs/, n., pl. calluses, v., callused, callusing.
n.
1. Pathol., Physiol.
a. a hardened or thickened part of the skin; a callosity.
b. a new growth of osseous matter at the ends of a fractured bone, serving to unite them.
2. Also, callose. Bot.
a. the tissue that forms over the wounds of plants, protecting the inner tissues and causing healing.
b. a deposit on the perforated area of a sieve tube.
c. (in grasses) a tough swelling at the base of a lemma or palea.
v.i.
3. to form a callus.
v.t.
4. to produce a callus or calluses on: Heavy work callused his hands.
[1555-65; < L callus, masc. var. of callum; see CALLOUS]

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In botany, soft tissue that forms over a wounded or cut plant surface, leading to healing.

A callus arises from cells of the cambium. When a callus forms, some of its cells may organize into growing points, some of which in turn give rise to roots while others produce stems and leaves. Thus a callus may be capable of regenerating an entire plant.

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botany
      In botany, soft tissue that forms over a wounded or cut plant surface, leading to healing. A callus arises from cells of the cambium. When a callus forms, some of its cells may organize into growing points, some of which in turn give rise to roots while others produce stems and leaves. Thus a callus may be capable of regenerating an entire plant.

also spelled  Callous,  

      in dermatology, small area of thickened skin, caused by continued friction, pressure, or other physical or chemical irritants. In response to mild but repeated injury, the cells of the epidermis, the outermost horny layer of the skin, become more active, giving rise to a localized increase in horny tissue on the surface of the skin. Calluses are most frequently seen on the hands and feet. They are usually yellowish white, flat, and painless. When a callus is conical in shape, penetrating into the deeper layer of the skin and causing pain when pressed, it is called a corn.

also spelled  callous 

      in osteology, bony and cartilaginous material forming a connecting bridge across a bone fracture during repair. Within one to two weeks after injury, a provisional callus forms, enveloping the fracture site. Osteoblasts (osteoblast), bone-forming cells in the periosteum (the bone layer where new bone is produced), proliferate rapidly, forming collars around the ends of the fracture, which grow toward each other to unite the fragments. The definitive callus forms slowly as the cartilage is resorbed and replaced by bone tissue. Two to three weeks after injury, strong bony extensions join the fractured bone ends, and the organized aspect of bone gradually recurs. The callus is resorbed over a period of months to years.

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Universalium. 2010.

Look at other dictionaries:

  • Callús — Saltar a navegación, búsqueda Callús Bandera …   Wikipedia Español

  • Callús — Vue générale …   Wikipédia en Français

  • Callus — oder Kallus (lat. für ‚harte Haut‘ oder ‚Schwiele‘, fachlich eine Ansammlung undifferenzierter oder nicht vollständig differenzierter Zellen) nennt man: bei Tieren und beim Menschen Starkwuchs an den Bruchstellen von Knochenbrüchen, siehe Kallus… …   Deutsch Wikipedia

  • CALLUS — item nucleus, de margaritis, apud Plin. l. 9. c. 35. Sani quidem partus multiplici constant cute, non improprie Callum ut existimuri corporis possit. Et paulo post, Multô deinde obrutas sule in vasis sictilibus, erosa carne omni, nucleos quosdam… …   Hofmann J. Lexicon universale

  • callus — (n.) hardened skin, 1560s, from L. callus, variant of callum hard skin, related to callere be hard, and cognate with Skt. kalika bud, O.Ir. calath hard, O.C.S. kaliti to cool, harden …   Etymology dictionary

  • callus — [kal′əs] n. pl. calluses [L, var. of callum, hard skin] 1. a hardened, thickened place on the skin 2. the hard substance that forms at the break in a fractured bone and serves to reunite the parts 3. a disorganized mass of cells that develops… …   English World dictionary

  • Callus — Cal lus (k[a^]l l[u^]s), n. [L. See {Callous}.] 1. (Med.) (a) Same as {Callosity}. (b) The material of repair in fractures of bone; a substance exuded at the site of fracture, which is at first soft or cartilaginous in consistence, but is… …   The Collaborative International Dictionary of English

  • callus — callus. См. каллюс. (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.

  • Callus — (lat.), 1) Schwiele der Haut durch anhaltenden Druck an den Füßen, Händen etc., bei harter Handarbeit, vielem Barfußengehen entstandene Verdickung der Haut; 2) gleiche gutartige Verhärtung der Haut, in häutigen u. anderen weichen Gebilden, bes.… …   Pierer's Universal-Lexikon

  • Callus — (lat., »Schwiele«), die sich neu bildende Knochenmasse, durch welche die Heilung von Knochenbrüchen (s.d.) bewirkt wird. Callös nennt man auch ein als Abschluß von Entzündungsprozessen entstehendes derbes, sehniges, narbiges Gewebe. – In der… …   Meyers Großes Konversations-Lexikon

  • Callus — (lat.), Schwiele, Knorpel; das neu gebildete Knochengewebe bei Knochenbrüchen; wulstige Wucherungen an Pflanzen zum Abschluß von Wunden …   Kleines Konversations-Lexikon


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