osteon

osteon

 the chief structural unit of compact (cortical) bone, consisting of concentric bone layers called lamellae, which surround a long hollow passageway, the Haversian canal (named for Clopton Havers, a 17th-century English physician). The Haversian canal contains small blood vessels responsible for the blood supply to osteocytes (osteocyte) (individual bone cells). Osteons are several millimetres long and about 0.2 millimetre (0.008 inch) in diameter; they tend to run parallel to the long axis of a bone.

      Osteons are formations characteristic of mature bone and take shape during the process of bone remodeling, or renewal. New bone may also take this structure as it forms, in which case the structure is called a primary osteon. The process of the formation of osteons and their accompanying Haversian canals begins when immature woven bone and primary osteons are destroyed by large cells called osteoclasts (osteoclast), which hollow out a channel through the bone, usually following existing blood vessels. Layers of bone-forming cells, or osteoblasts (osteoblast), follow the osteoclasts and lay down new bone on the sides of the channel; the layers of bone built up in this way slowly narrow the channel until a tunnel not much larger than the central blood vessel remains. The blood supply for the osteocytes then passes through these channels, the Haversian canals. The spaces between adjacent osteons are filled with interstitial lamellae, layers of bone that are often remnants of previous Haversian systems. Transverse vessels, which run perpendicular to the long axis of the cortex, are called Volkmann canals; Volkmann canals connect adjacent osteons and also connect the blood vessels of the Haversian canals with the periosteum, the tissue covering the bone's outer surface.

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Universalium. 2010.

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  • Osteon — Diagram of compact bone from a transverse section of a long bone s cortex. Gray s subject #18 89 …   Wikipedia

  • Osteon — ⇒ Lamellenknochen …   Deutsch wörterbuch der biologie

  • Osteon — Schematischer Aufbau eines Röhrenknochens. Ein Osteon (von griech. osteo „Knochen“; Mz. Osteonen; auch Havers System nach Clopton Havers) ist die funktionelle Grundeinheit der Kortikalis (Substantia compacta) eines Röhrenknochens. Ein Osteon… …   Deutsch Wikipedia

  • Osteon — Os|te|on das; s, ...onen <aus gr. ostéon »Knochen«> Baustein des Knochengewebes (Med.) …   Das große Fremdwörterbuch

  • osteon — I. ˈästēˌän noun combining form ( s) Etymology: New Latin, from Greek osteon bone more at osseous : bone : bone part lophosteon …   Useful english dictionary

  • Osteon primarium — pirminis osteonas statusas T sritis gyvūnų raida, augimas, ontogenezė, embriologija atitikmenys: lot. Osteon primarium ryšiai: platesnis terminas – pirminis kaulas …   Veterinarinės anatomijos, histologijos ir embriologijos terminai

  • Osteon secundarium — antrinis osteonas statusas T sritis gyvūnų raida, augimas, ontogenezė, embriologija atitikmenys: lot. Osteon secundarium ryšiai: platesnis terminas – galutinis tankusis kaulas …   Veterinarinės anatomijos, histologijos ir embriologijos terminai

  • Osteon primarium — pirminis osteonas statusas T sritis embriologija atitikmenys: lot. Osteon primarium ryšiai: platesnis terminas – pirminis kaulas …   Medicininės histologijos ir embriologijos vardynas

  • Osteon secundarium — antrinis osteonas statusas T sritis embriologija atitikmenys: lot. Osteon secundarium ryšiai: platesnis terminas – galutinis tankusis kaulas …   Medicininės histologijos ir embriologijos vardynas

  • osteon — noun Any of the central canals, and surrounding bony layers, found in compact bone. Syn: Haversian system, osteone …   Wiktionary

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