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The Skeletal System- Osseous Tissue & Skeletal Structure.

Date post: 12-Jan-2016
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The Skeletal System- Osseous Tissue & Skeletal Structure
Transcript
  • The Skeletal System-Osseous Tissue & Skeletal Structure

  • The skeletal system includes:BonesCartilageJointsLigamentsOther connective tissues

  • Functions of the Skeletal SystemSupport against gravityProtection of soft internal organsMovement (Leverage)StorageMinerals (calcium, phosphorous) within the matrix of bone tissueEnergy reserve (adipose) within the yellow marrow of long bonesBlood cell production within red marrow of spongy bone tissue

  • Bone tissueAnatomy of a boneStructure of bone tissueFormation and growth of boneFracture and repairEffects of physiological processes on bone

  • Long bonesShort bonesFlat bonesIrregular bonesSesamoid bonesSutural bonesAnatomical Classification of BonesBones are classified by their basic shape

  • The parts of a long boneDiaphysis-shaftEpiphyses- endsCome together at metaphysesArticular cartilage protects epiphysesPeriosteum covers bone Medullary cavity contains marrow; is lined by endosteum

  • Bone cells

  • Organization of bone tissuecompactspongy

  • Compact vs. spongy boneCompact boneExternal layerArranged in osteonsLamellae are found around periphery and between osteonsCentral canals connected to each other by perforating canalsSpongy boneNo osteonsArranged in trabeculaeMajor type of tisse in short, flat, irregular bonesMuch lighter than compact boneSupports red bone marrow

  • Blood and nerve supply to boneAbundant supply of bloodMay have several nutrient arteriesNerves accompany blood vessels

  • Ossification (osteogenesis)Bone forms within mesenchyme in layers (intramembranous)Flat bones of skull and mandibleOsteocytes secrete calciumCompact and spongy bone form

  • Bone remodeling replaces old tissueResorption by osteoclasts, deposition by osteoblastsStrengthens boneRepairs damaged bone

  • The Structure of a Typical BoneAll bones have a combination of spongy (cancellous) & compact (dense) bone tissue

  • The Histological Features of Compact BoneOsteon/Haversian system - basic functional unit of compact bone

    Concentric lamellae (layers) of matrix surrounding central (Haversian) canalOsteocytes located within lacunaeCanaliculi branch out radially from lacunaeCentral canals (containing BVs) run vertically down the length of the bone

    Perforating (Volkmanns) canals (containing BVs) run horizontally across the width

  • Bone CellsIn addition to Osteocytes, the mature bone cells found within the matrix of bone tissue, there are three other cells that are associated with bonesOsteoprogenitor cellsOsteoblastsOsteoclasts

  • Bone CellsOsteoprogenitor cellsDerived from mesenchymal cellsCan undergo mitosisMature into osteoblasts

  • Bone CellsOsteoblastsResponsible for osteogenesis create bone tissueMature into osteocytes

  • Bone CellsOsteoclastsDerived from embryological WBCsSecrete enzymes for osteolysis resorb/break down bone tissueNecessary for calcium homeostasis

  • Structure of a Typical Long Bone

  • The Structure of a Long Bone

  • The Structure of a Long Bone

  • The Structure of a Long Boneepiphysisepiphysismetaphysis location of epiphyseal plate in children epiphyseal line in adultsdiaphysismetaphysisarticular cartilage

  • The Structure of a Long Bonemedullary cavity filled with yellow marrow in adults lined with endosteum

  • The Structure of a Long Boneperiosteum

  • Bone Formation and GrowthOssification - Process of converting other tissues to bone; begins around week 6-8 of embryological developmentTwo types of ossification processes occur during embryological formation: IntramembranousEndochondral

  • An Overview of the SkeletonSkeletal DivisionsAxial skeleton (80 bones)SkullThoracic cage and sternumVertebral columnAppendicular skeleton (126 bones)Upper, lower limbsPectoral girdlePelvic girdleThere are 206 bones in the adult human body

  • Types of fractureStress fracture is not visible;Overuse or degeneration

  • Process of fracture repairBone grows slowly; blood supply may be affected

  • Life processes and bone formationWhy is exercise good for bones?How does aging affect bones?Loss of bone mass due to calcium lossDecreased production of collagen

  • Treatment of osteoporosisPreventionSteroid hormone replacement (stimulates osteoblast activity)Evista has estrogen-like effects on bone formationFosamax blocks bone resorption

  • SummaryBone is a complex tissueIt is constantly being remodeledBones consist of compact and spongy bone, lots of blood vessels and nervesFunctions of bone:Support and protectionMovementCalcium levelsBlood cell formationFat storage

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