Osteon - wikipedia Osteon This article has multiple issues. Please help improve it or discuss these issues on the talk page. ( Learn how and when to remove these template messages ) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( December 2008 ) This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. Please help to improve this article by introducing more precise citations. ( December 2008 ) Osteon Diagram of compact bone from a transverse section of a long bone 's cortex. Details Latin Osteon Dorlands / Elsevier o_08 / 12601039 Anatomical terminology ( edit on Wikidata ) Diagram of a typical long bone showing both compact ( cortical ) and cancellous ( spongy ) bone. Histology of Osteon. The osteon or haversian system / həˈvɜːr. ʒən / ( named for Clopton Havers ) is the fundamental functional unit of much compact bone. Osteons are roughly cylindrical structures that are typically several millimeters long and around 0.2 mm in diameter. They are present in many bones of most mammals and some bird, reptile, and amphibian species. Contents 1 Structure 1.1 Drifting osteons 2 Investigative applications 3 See also 4 References 5 Bibliography 6 External links Structure Histology of compact bone showing osteon Each osteon consists of concentric layers, or lamellae, of compact bone tissue that surround a central canal, the haversian canal. The haversian canal contains the bone 's blood supplies. The boundary of an osteon is the cement line. Each haversian canal is surrounding by varying number ( 5 - 20 ) of concentrically arranged lamellae of bone matrix. Near the surface of the compact bone, the lamellae are arranged parallel to the surface ; these are called circumferential lamellae. Some of the osteoblasts develop into osteocytes, each living within its own small space, or lacuna. Osteocytes make contact with the cytoplasmic processes of their counterparts via a network of small transverse canals, or canaliculi. This network facilitates the exchange of nutrients and metabolic waste. Collagen fibers in a particular lamella run parallel to each other, but the orientation of collagen fibers within other lamellae is oblique. The collagen fiber density is lowest at the seams between lamellae, accounting for the distinctive microscopic appearance of a transverse section of osteons. The space between osteons is occupied by interstitial lamellae, which are the remnants of osteons that were partially resorbed during the process of bone remodeling. Osteons are connected to each other and the periosteum by oblique channels called Volkmann 's canals or perforating canals. Drifting osteons Drifting osteons are a phenomenon that is not fully understood. A `` drifting osteon '' is classified as one that runs both longitudinally as well as transversely through the cortex. An osteon can `` drift '' in one direction or change directions several times, leaving a tail of lamellae behind the advancing haversian canal. Investigative applications In bioarchaeological research and in forensic investigations, osteons in a bone fragment can be used to determine the sex of an individual and age, as well as aspects of taxonomy, diet, health and motor history. Osteons and their arrangement vary according to taxon, so that genus and sometimes species can be differentiated using a bone fragment not otherwise identifiable. However, there is considerable variability among the different bones of a skeleton, and features of some faunal osteons overlap with those of human osteons ; therefore, examination of osteons is not of primary use in the analyses of osteological remains. More research is needed, but osteohistology has the potential to positively affect the studies in bioarchaeology, paleontology and forensic investigations. In recent decades, osteohistological studies of dinosaur fossils has been used to address a number of issues, such as the periodicity of growth of dinosaurs and whether it was uniform across species and the question of whether dinosaurs were warm - blooded or not. See also Haversian canals Cortical bone ( compact bone ) Cancellous bone ( spongy bone containing ) References Jump up ^ `` Osteon, '' Encyclopædia Britannica Online ( 2009 ) ; retrieved 23 June 2009. Jump up ^ Robling, Alexander D. ; Stout, Sam D. 1999 `` Morphology or the Drifting Osteon, '' Cells Tissues Organs 164 : 192 - 204 Jump up ^ Monika Martiniaková, Radoslav Omelka, Birgit Grosskopf, Alexander V. Sirotkin, and Peter Chrenek, 2008, `` Sex - related variation in compact bone microstructure of the femoral diaphysis in juvenile rabbits, '' Acta Vet Scand. 50 ( 1 ) : 15ff Jump up ^ Pfeiffer, Susan ; Crowder, Christian ; Harrington, Lesley ; and Brown, Michael, 2006, `` Secondary osteon and haversian canal dimensions as behavioral indicators, '' American Journal of Physical Anthropology, 131 ( 4 ) : 460 - 468 Jump up ^ Martiniaková, Monika. 2006. Differences in Bone Microstructure of Mammalian Skeletons. Faculty of Natural Sciences, Constantine the Philosopher University in Nitra : Nitra, Slovakia Jump up ^ Chinsamy, Anusuya ( 1995 ). `` Ontogenetic Changes in the Bone Histology of the Late Jurassic Ornithopod ' Dryosaurus Lettowvorbecki ' ''. Journal of Vertebrate Paleontology. 15 ( 1 ) : 96 -- 104. doi : 10.1080 / 02724634.1995. 10011209. Jump up ^ Reid, R.E.H. ( 1984 ). `` Primary Bone and Dinosaurian Physiology ''. Geological Magazine. 121 ( 6 ) : 589 -- 598. doi : 10.1017 / S0016756800030739. Bibliography Cooper, Reginald R. ; Milgram, James W. ; and Robinson, Robert A. 1966 `` Morphology of the Osteon : An Electron Microscopic Study, '' Journal of Bone and Joint Surgery, 48 : 1239 - 1271. Martiniaková, Monika 2006 Differences in bone microstructure of mammalian skeletons. Faculty of Natural Sciences, Constantine the Philosopher University in Nita : Nitro, Slovakia. Netter, Frank H. ( 1987 ), Musculature system : anatomy, physiology, and metabolic disorders. Summit, New Jersey : Chiba - Geiger Corporation ISBN 0 - 914168 - 88 - 6 Pfeiffer, Susan ; Crowder, Christian ; Harrington, Lesley ; and Brown, Michael 2006 `` Secondary osteon and haversian canal dimensions as behavioral indicators, '' American Journal of Physical Anthropology, 131 ( 4 ) : 460 - 468. Robling, Alexander D. ; Stout, Sam D. 1999 `` Morphology of the drifting osteon, '' Cells Tissues Organs 164 : 192 - 204 External links SLIBS Bone Website : http://www.trinity.edu/stonily/bone/intro2.htm Bone - BioWeb at University of Wisconsin System Histology of osteons video explaining osteons : https://www.youtube.com/watch?v=ylmanEGjRuY Bone and cartilage Cartilage perichondrium fibrocartilage callus metaphysis Cells chondroblast chondrocyte Types hyaline elastic fibrous Bone Ossification Primary bone intramembranous endochondral Cells osteoblast osteoid osteocyte osteoclast Types cancellous cortical Regions subchondral bone epiphysis epiphyseal plate / metaphysis diaphysis Condyle Epicondyle Structure Osteon Haversian canals Volkmann 's canals connective tissue endosteum periosteum Sharpey 's fibres enthesis lacunae canaliculi trabeculae medullary cavity bone marrow Shapes long short flat irregular sesamoid Retrieved from `` https://en.wikipedia.org/w/index.php?title=Osteon&oldid=811184228 '' Categories : Skeletal system Hidden categories : Articles needing additional references from December 2008 All articles needing additional references Articles lacking in - text citations from December 2008 All articles lacking in - text citations Articles with multiple maintenance issues Medicine infobox template using GraySubject or GrayPage Medicine infobox template using Dorlands parameter All articles with dead external links Articles with dead external links from September 2016 Talk Contents About Wikipedia Български Català Čeština Ελληνικά Español فارسی Français Italiano Қазақша Nederlands Polski Português Русский Simple English Slovenčina Svenska Українська Edit links This page was last edited on 20 November 2017, at 01 : 26. 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Question: where is the matrix located in the osteon
Answer: haversian canal