WordNet

(physical chemistry) a sample of matter in which substances in different phases are in equilibrium; "in a static system oil cannot be replaced by water on a surface"; "a system generating hydrogen peroxide"
instrumentality that combines interrelated interacting artifacts designed to work as a coherent entity; "he bought a new stereo system"; "the system consists of a motor and a small computer"
a group of independent but interrelated elements comprising a unified whole; "a vast system of production and distribution and consumption keep the country going" (同)scheme
a complex of methods or rules governing behavior; "they have to operate under a system they oppose"; "that language has a complex system for indicating gender" (同)system of rules
a group of physiologically or anatomically related organs or parts; "the body has a system of organs for digestion"
a procedure or process for obtaining an objective; "they had to devise a system that did not depend on cooperation"
the living body considered as made up of interdependent components forming a unified whole; "exercise helped him get the alcohol out of his system"

PrepTutorEJDIC

〈C〉(関連した部分から成る)『体系』,系統,組織[網],装置 / 〈C〉(教育・政治などの)『制度』,機構;《the~》体制 / 〈C〉(思想・学問などの)『体系』,学説 / 〈C〉(…の)『方法』,方式,やり方《+of doing》 / 〈U〉正しい方針(筋道,順序) / 〈U〉《the~》(身体の)組織,系統 / 〈U〉《the~,one's~》身体,全身

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/03/03 23:07:48」(JST)

wiki en

Diagram of a typical long bone showing both compact (cortical) and cancellous (spongy) bone.

The osteon or haversian system /həˈvɜr.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 0.2mm in diameter.^[1] They are present in many bones of most mammals and some bird, reptile, and amphibian species.

Description[edit]

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 nerve and blood supplies. The boundary of an osteon is the cement line.

Between adjoining osteons, there are angular intervals that are occupied by interstitial lamellae. These lamellae are remnants of osteons that have been mostly destroyed. 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[edit]

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.^[2]

Investigative applications[edit]

In bioarchaeological research and in forensic investigations, osteons in a bone fragment can be used to determine the sex of an individual^[3] and age, as well as aspects of health and motor history^[4] and diet.

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.^[5] More research is needed, but 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 ^[6] and the question of whether dinosaurs were warm-blooded or not ^[7]

References[edit]

^ "Osteon," Encyclopædia Britannica Online (2009); retrieved 23 June 2009.
^ Robling, Alexander D.; Stout, Sam D. 1999 "Morphology or the Drifting Osteon," Cells Tissues Organs 164:192-204
^ 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
^ 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
^ Martiniaková, Monika. 2006. Differences in Bone Microstructure of Mammalian Skeletons. Faculty of Natural Sciences, Constantine the Philosopher University in Nitra: Nitra, Slovakia
^ 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
^ Reid, R. E. H., 1984, "Primary Bone and Dinosaurian Physiology," 'Geological Magazine' 121(6): 589-598. DOI: http://dx.doi.org/10.1017/S0016756800030739

Bibliography[edit]

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[edit]

SLIBS Bone Website: http://www.trinity.edu/stonily/bone/intro2.htm
Bioweb at UWLAX Bone
Histology of osteons
video explaining osteons: http://www.youtube.com/watch?v=ylmanEGjRuY

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 非ホジキンリンパ腫による中枢神経系の二次性障害 secondary involvement of the central nervous system by non hodgkin lymphoma
2. 心不全におけるアンギオテンシン変換酵素阻害剤およびアンギオテンシン受容体拮抗剤：
作用機序 angiotensin converting enzyme inhibitors and receptor blockers in heart failure mechanisms of action
3. 中枢神経系の原発性血管炎 primary angiitis of the central nervous system
4. 高血圧治療におけるレニン・アンギオテンシン系阻害 renin angiotensin system inhibition in the treatment of hypertension
5. 肝細胞癌における病期分類および予後因子 staging and prognostic factors in hepatocellular carcinoma

English Journal

Deuterium nuclear magnetic resonance unambiguously quantifies pore and collagen-bound water in cortical bone.

Ong HH, Wright AC, Wehrli FW.SourceLaboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA.
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.J Bone Miner Res.2012 Jul 13. doi: 10.1002/jbmr.1709. [Epub ahead of print]
Bone water (BW) plays a pivotal role in nutrient transport and conferring bone with its viscoelastic mechanical properties. BW is partitioned between the pore spaces of the Haversian and lacuno-canalicular system, and water predominantly bound to the matrix proteins (essentially collagen). The gener
PMID 22807107

Distribution of microcrack lengths in bone in vivo and in vitro.

Presbitero G, O'Brien FJ, Lee TC, Taylor D.SourceTrinity Centre for Bioengineering, Trinity College Dublin, College Green, Dublin 2, Ireland. presbitg@tcd.ie
Journal of theoretical biology.J Theor Biol.2012 Jul 7;304:164-71. Epub 2012 Apr 5.
It is well known that bone contains small cracks; in vivo these microcracks are constantly growing and being repaired. Too rapid crack growth leads to stress fractures or fragility fractures. In vitro, changes occur in this population of microcracks when subjected to cyclic loading up to and includi
PMID 22498804

Japanese Journal

Three-Dimensional Anisotropy of Ultrasonic Wave Velocity in Bovine Cortical Bone: Effects of Hydroxyapatite Crystallites Orientation and Microstructure

Nakatsuji Tomohiro,Yamamoto Kazufumi,Suga Daisuke [他],Yanagitani Takahiko,Matsukawa Mami,Yamazaki Kaoru,Matsuyama Yukihiro
Jpn J Appl Phys 50(7), 07HF18-07HF18-6, 2011-07-25
… Bovine cortical bone has two typical microstructures, plexiform and haversian. … Two spherical specimens (diameter: 9 mm) were obtained from the anterior (plexiform) and posterior (haversian) parts of a 30-month-old bovine femur. … The three-dimensional anisotropy of longitudinal wave velocity was measured using a conventional ultrasonic pulse system by rotating the spherical specimen in the axial--tangential (A--T), axial--radial (A--R), and radial--tangential (R--T) planes. …
NAID 150000057687

Ultrasonic Wave Properties in Bone Axis Direction of Bovine Cortical Bone

Yamamoto Kazufumi,Yaoi Yuichiro,Yamato Yu [他],Yanagitan Takahiko,Matsukawa Mami,Yamazaki Kaoru
Jpn J Appl Phys 47(5), 4096-4100, 2008-05-25
… Bovine cortical bone has two typical microstructures, plexiform and Haversian. … SOS was measured with a conventional ultrasonic pulse system. …
NAID 150000050636