HumanAnatomy Unit1 OSTEOLOGY InAnatomyToday FunctionsoftheSkeletalSystem: • • • • • • • Support Movement Protection Hemopoiesis Electrolytebalance(Ca2+/PO4-3) Acid-basebalance Storageofheavymetals GeneralClassificationofIndividualBones • Byshape – Long – Short – Flat – Irregular • Shortbones • Longbones – longerthanwide – haveamarrow cavity – Ex:femur, humerus – Cubeshaped – Carpalsandtarsal • Flatbones – Broadsurfacesformuscle attachment – Encloseandprotectsoft organs – Ex:roofingbonesofskull, scapula,clavicle • Irregularbones – Variedshapes – Prominentsurfaces – Ex:vertebrae,sphenoid bone GeneralClassificationofIndividualBones byDevelopmentalLocation • Sesamoid – intramembranous developmentwithina tendon – Ex:patella • Sutural(Wormian) - intramembranous developmentwithina suture BoneStructure • Compactbone – Solidbonetissue – Haversiansystem=osteon • Concentriclamellaeandcentralcanal • Lacunae,canaliculi • Spongybone – Firstbonetissuetobelaiddownduringbone development – Trabeculae=latticeofthinplates • Spicules=rodsandspinesfusetogethertoformtrabeculae • Trabeculaelaiddownbasedonlinesofforce – Porous,filledwithredbonemarrow – Arrangedinlamellae,butfewosteons – Lightweight+strengthtobone CompactandSpongyBone CompactBoneTissue BoneMarrow • Red – Myeloidtissue • Origininbonemarrow – Distributioninchildvs.adult – Hematopoietic • Multipotantstemcells • Giverisetoallbloodcelltypes • Yellow – Fattymarrowreplacesredbonemarrowin adults – Nothematopoietic • Severeorchronicanemiaorbloodloss • Canrevertbacktoredbonemarrow StemCells • TotipotentStemCells – Cangiverisetoanyfetalandadultcellinthebody • zygote • Pluripotent – Cangiverisetoanyadultcellinthebody – After4daysofcelldivision,cellsthatareproduced becomepluripotent • Multipotent – Cangiverisetoalimitednumberofcelllineswithina tissuetype • Hematopoieticstemcells HistologyofOsseousTissue • ConnectiveTissue – Matrix • Non-livinggroundsubstance,stuff • Composition – 85%Hydroxyapatitecrystals » Ca10(PO4)6(OH)2 – 10%CaCO3 – Otherminerals » Mg,Na,K,Fl,etc. – collagen – Cells CellsofBoneTissue • OsteoprogenitorCells – linetheinnerperiosteum – producenewbonecells throughmitosis • Osteoblasts – secretematrix – highmetabolicrate – Osteoblaststrappedin lacunae • Osteocytes – highlybranched – surroundedbymatrix – lowmetabolicrate • Osteoclasts – fixedmacrophage – Breakdownoldbone cells • Boneliningcells – linethesurfaceofbones – regulatecalciumand phosphoruspassage Myeloidprogenitorcells Multinucleated <150mm indiameter Onbonesurface UseHCl to dissolve bone minerals
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