Diferenzas entre revisións de «Osteoblasto»

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[[Ficheiro:Active osteoblasts.jpg|thumb|right|Osteoblastos activos.]]
 
Os '''Osteoblastsosteoblastos''' (fromdo thegrego "[[Greek language|Greekóso]]" words fore "[[bone]]xerme" andou "germembrionario" or embryonic) areson mononucleateas [[cellcélulas (biology)|cell]]sencargadas thatda areformación responsibledo foróso, boneque formation;se inpoden essence, osteoblasts areconsiderar specializedcomo [[fibroblastfibroblasto]]s thatespecializados inque additionademais todos fibroblasticprodutos productsfibroblásticos, expressexpresan [[bonesialoproteína ósea|sialoproteínas sialoproteinóseas]] ande [[osteocalcinosteocalcina]].<ref name="Salentijn">Salentijn, L. ''Biology of Mineralized Tissues: Cartilage and Bone'', [[Columbia University College of Dental Medicine]] post-graduate dental lecture series, 2007</ref>
 
OsteoblastsOs produceosteoblastos producen a [[extracellularmatriz matrix|matrixextracelular]] ofdo [[osteoid]],tecido whichóseo is(osteoide), composedque mainlyestá ofcomposta Typeprincipalmente Ide [[collagencoláxeno]] de tipo I. OsteoblastsOs areosteoblastos alsoson responsibletamén forresponsables mineralizationda ofmineralización thisdesta matrixmatriz. ZincO [[cinc]], coppero and[[cobre]] e o [[sodio]] sodiumson arealgúns somedos ofións theminerais mineralsque requiredse inrequiren thisneste processproceso. BoneO isóso aé dynamicun tissuetecido thatdinámico isque constantlyestá beingconstantemente reshapedsendo byremodelado osteoblastspolos osteoblastos, inencargados chargeda ofprodución productionda ofmatriz matrixe anda parte mineral do tecido, ande polos [[osteoclastsosteoclasto]]s, whichque remodeldestrúen theparte do tecido durante a tissueremodelación. OsteoblastOs cellsosteoblastos tend totenden decreasea withdecrecer ageen número coa idade, affectingo theque afecta ao balance ofentre formationa andformación resorptione a inreabsorción thedo [[bonetecido tissueóseo]].<ref name=Dippolito1999>{{cite journal|author = D’ippolito, Gianluca|coauthors = Schiller, Paul C.; Ricordi, Camillo; Roos, Bernard A.; Howard, Guy A.|year = 1999|title = Age-Related Osteogenic Potential of Mesenchymal Stromal Stem Cells from Human Vertebral Bone Marrow|journal = Journal of Bone and Mineral Research|volume = 14|issue = 7|pages = 1115–1122|doi = 10.1359/jbmr.1999.14.7.1115|pmid = 10404011}}</ref>
 
==Osteoxénese==
Os osteoblastos orixínanse a partir de '''células osteoproxenitoras''' localizadas na capa profunda do [[periostio]] que rodea os ósos e na [[medula ósea]]. As células osteoproxenitoras son células inmaduras que expresan o [[factor de transcrición]] regulatorio principal [[Cbfa1|Cbfa1/Runx2]].
Osteoblasts arise from '''osteoprogenitor cells''' located in the deeper layer of [[periosteum]] and the [[bone marrow]]. Osteoprogenitors are immature [[progenitor cell]]s that express the master regulatory [[transcription factor]] [[Cbfa1|Cbfa1/Runx2]].
 
OsteoprogenitorsAs arecélulas inducedosteoproxenitoras toson differentiateinducidas undera thediferenciarse influencebaixo ofa influencia de [[growth factor de crecemento|factores de crecemento]]s, inen particular theas '''[[boneproteína morfoxenética ósea|proteínas morphogeneticmorfoxenéticas proteinóseas]]s''' (BMPs).<ref name="Agata, H. 2007">{{cite journal|doi=10.1177/154405910708600113|last1=Agata|first1=H|last2=Asahina|first2=I|last3=Yamazaki|first3=Y|last4=Uchida|first4=M|last5=Shinohara|first5=Y|last6=Honda|first6=MJ|last7=Kagami|first7=H|last8=Ueda|first8=M|title=Effective bone engineering with periosteum-derived cells.|journal=Journal of dental research|volume=86|issue=1|pages=79–83|year=2007|pmid=17189468}}</ref> AsideAdemais fromdas BMPs, otheroutros growthfactores factorsde includingcrecemento fibroblastcomo growtho factor de crecemento dos fibroblastos (FGF),<ref name="Agata, H. 2007"/> o [[platelet-derivedfactor growthde factorcrecemento derivado das plaquetas]] (PDGF) ande o [[transforming growth factor|transforming growthde factorcrecemento betatransformante]] beta (TGF-β) maypoden promotepromover thea divisiondivisión ofdas células osteoproxenitoras osteoprogenitorse andpotencialmente potentiallyincrementar increasea osteogenesisosteoxénese.
 
OnceUnha osteoprogenitorsvez startque toas differentiatecélulas intoosteoproxenitoras osteoblasts,comezan theya beginse todiferenciar expressen osteoblastos, empezan a rangeexpresar ofun geneticconxunto markersde marcadores xenéticos como includingo [[Osterix]], [[collagencolláxeno|Col1]],<ref name="Ringe, J. 2008">{{cite journal|last1=Ringe|first1=J|last2=Leinhase|first2=I|last3=Stich|first3=S|last4=Loch|first4=A|last5=Neumann|first5=K|last6=Haisch|first6=A|last7=Häupl|first7=T|last8=Manz|first8=R|last9=Kaps|first9=C|title=Human mastoid periosteum-derived stem cells: promising candidates for skeletal tissue engineering.|journal=Journal of tissue engineering and regenerative medicine|volume=2|issue=2-3|pages=136–46|year=2008|pmid=18383554|doi=10.1002/term.75}}</ref> [[Bonesialoproteína sialoproteinósea|BSP]], [[Macrophagefactor colony-stimulatingestimulante factordas colonias de macrófagos|M-CSF]], [[alkalinefosfatase phosphatasealcalina|ALP]],<ref>{{cite journal|last1=Szulc|first1=P|last2=Garnero|first2=P|last3=Marchand|first3=F|last4=Duboeuf|first4=F|last5=Delmas|first5=PD|title=Biochemical markers of bone formation reflect endosteal bone loss in elderly men--MINOS study.|journal=Bone|volume=36|issue=1|pages=13–21|year=2005|pmid=15663998|doi=10.1016/j.bone.2004.09.004}}</ref> [[osteocalcinosteocalcina]],<ref name="Ringe, J. 2008"/> [[osteopontinosteopontina]], ande [[osteonectinosteonectina]]. AlthoughAínda theque termo osteoblasttermo impliesosteoblasto animplica immatureun celltipo typede célula inmadura, osteoblastsos areosteoblastos inson factde thefeito maturecélulas boneóseas cellsmaduras entirelyenteiramente responsibleresponsables forda generatingxeración bonedo tissuetecido inóseo animalsen andanimais e humanshumanos.
 
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