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OSTEOLOGYHumanAnatomyUnit1
InAnatomyToday
FunctionsoftheSkeletalSystem
• Mechanicalsupportformovement• Protectionofinternalorgans• Hemopoiesis• Homeostasis• Mineralhomeostasis• Electrolytebalance(Ca2+/PO4
-3)• Acid-basebalance
• Storageofheavymetals• Cadmium,Nickel,Mercury,Chromium,Lead,Aluminum,Titanium,Iron,Arsenic
BoneTissue
• OsseousTissue• Adynamictissuethatisconstantlyremodeled• Oldbonetissueisdegraded• Newbonetissueisproduced
• Classifiedasaconnectivetissue• Bonetissueismadeupofdifferenttypesofbonecellsandbonematrix• 2typesofbonetissue
• Spongybonetissue• Compactbonetissue
BoneCellTypes
• Osteoprogenitor Cells• Stemcells• Linetheinnerperiosteum• Producenewbonecellsthroughmitosis
• Osteoblasts• Newlyformedbonecells• Secretematrix• Highmetabolicrate• Osteoblastsbecometrappedinlacunae
• Osteocytes• Maturebonecells• Highlybranched• Surroundedbymatrix• Lowmetabolicrate
• Boneliningcells• linethesurfaceofbones• regulatecalciumandphosphoruspassage
• Osteoclasts• fixedmacrophage• Breakdownbonematrix
BoneCellTypes
BoneMatrix
• Organiccomponent∼ 30%byweight• Calledosteoid• PredominantlycomprisedofaproteincalledtypeIcollagenfibers∼ 90%
• Non-collagenousproteins∼ 10%• Over30types• Proteoglycans• Glycoproteins
• Inorganiccomponent∼ 60%byweight• Saltsandminerals• 85%Hydroxyapatitecrystals
• Ca10(PO4)6(OH)2• 10%CaCO3• Otherminerals
• Mg,Na,K,Fl,etc.
• Water∼ 10%byweight
SpongyBoneTissueCancellousBoneTissue
• Firstbonetissuepresentduringbonedevelopment• Madeupoftrabeculae• Latticeofthinplates• Trabeculaelaiddownbasedonlinesofforce
• Spongyboneisporous• Decreasestheweightofboneswithoutcompromisingstrength
• The“pores”arefilledwithredbonemarrow
CompactBoneTissue
• Solidbonetissue• Noporespresent
• Madeupofmanyosteons• Haversiancanalsystem• Osteonsrunparalleltotheaxisofthebone
• Bonetissueisarrangedinlamellaearoundacentralcanal
• Centralcanalprovidearouteforbloodvessels/lymphatics/nerves• Runparalleltotheaxisofthebone
• Perforatingcanalsprovidearouteforbloodvessels/lymphatics/nerves• Perpendiculartotheaxisofthebone
HistologyofBoneTissue
SpongyBoneTissue CompactBoneTissue
BoneMarrow
• Bonemarrowfillsinthespaceinbones• Fillsinthe“pores”ofspongybone• Fillsthemarrow/medullarycavityoflongbones
• 2typesofbonemarrow• Redmarrow- hemopoiesis• Yellow/fattymarrow– fatstorage
• Distributionchangesasyougrow
GeneralClassificationofIndividualBones
• Byshape• Long• Short• Flat• Irregular
• Bydevelopmentallocation• Withinatendon• Withinasuture
LongBones
• Characteristics• Supporttheweightofthebody• Providemovement• Haveamarrowcavity
• Longbonesinthehumanbody• Humerus• Radius• Ulna• Femur• Tibia• Fibula• Metacarpals,metatarsals• Phalanges
ShortBones
• Characteristics– Cubeshaped– Providesupportandstability– Onlyasmallamountofmovementbetweenshortbones
• Shortbonesinthehumanbody– Carpals– Tarsals
FlatBones
• Characteristics• Broad,flatsurface(s)formuscleattachment• Providephysicalprotectionforinternalorgans
• FlatbonesinthehumanbodyFrontal Vomer
Parietal Sternum
Occipital Ribs
Nasal Scapula
Lacrimal Ilium
IrregularBones
• Characteristics– Variedshapes– Prominentsurfaces
• IrregularbonesinthehumanbodyVertebrae Zygomatic
Sacrum Maxilla
Coccyx Mandible
Temporal Palatine
Sphenoid Inferiornasalconcha
Ethmoid Hyoid
SesamoidBones
• Characteristics• Abonethatcompletelyorpartiallyembeddedwithintendons
• Small• Round(ish)• Reducefrictionoftendonsatjointsurfaces
• Protecttendonsfromdirecttrauma• Exampleinthehumanbody
• Patella• Bonesintheballofthefoot
• Calledsesamoidbones• Beneaththehallux• VariableinotherMTPjoints
SuturalBones(Wormian Bones)
• Characteristics• Extrabones/piecesthatdevelopwithinasutureintheskull• Possiblylinkedtorapidskullexpansion• Small• Foundmorecommonlyinmalesthanfemales