2 Anat 35 Osteology

HumanAnatomy
Unit1
OSTEOLOGY
InAnatomyToday
FunctionsoftheSkeletalSystem:
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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