The Skeletal System Parts of the skeletal system Bones (skeleton) Joints Cartilages Ligaments ...

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Transcript of The Skeletal System Parts of the skeletal system Bones (skeleton) Joints Cartilages Ligaments ...

  • The Skeletal SystemParts of the skeletal systemBones (skeleton)JointsCartilagesLigamentsDivided into two divisionsAxial skeleton longitudinal axisAppendicular skeleton limbs and girdles

  • Functions of BonesSupport of the bodyProtection of soft organs esp. with skull, ribs, thoraxMovement due to attached skeletal muscles via tendonsStorage of minerals and fats Ca, PBlood cell formation - hematopoiesis

  • Bones of the Human BodyThe skeleton has 206 bonesTwo basic types of bone tissueCompact boneDense and smoothSpongy boneSmall needle-like pieces of boneMany open spacesFigure 5.2b

  • Classification of BonesLong bonesTypically longer than wideHave a shaft with heads at both endsContain mostly compact boneExamples: Femur, humerus

  • Classification of BonesShort bonesGenerally cube-shapeContain mostly spongy boneExamples: Carpals, tarsals

  • Classification of Bones on the Basis of ShapeFigure 5.1

  • Classification of BonesFlat bonesThin and flattenedUsually curvedThin layers of compact bone around a layer of spongy boneExamples: Skull, ribs, sternum

  • Classification of BonesIrregular bonesIrregular shapeDo not fit into other bone classification categoriesExample: Vertebrae and hip

  • Gross Anatomy of a Long BoneDiaphysisShaftComposed of compact boneEpiphysis Ends of the boneComposed mostly of spongy boneFigure 5.2a

  • Structures of a Long BonePeriosteumOutside covering of the diaphysisFibrous connective tissue membraneSharpeys fibersSecure periosteum to underlying boneArteriesSupply bone cells with nutrientsFigure 5.2c

  • Structures of a Long BoneArticular cartilageCovers the external surface of the epiphysesMade of hyaline cartilageDecreases friction at joint surfacesFigure 5.2a

  • Structures of a Long BoneMedullary cavityCavity of the shaftContains yellow marrow (mostly fat) in adultsContains red marrow (for blood cell formation) in infantsFigure 5.2a

  • Bone MarkingsSurface features of bonesSites of attachments for muscles, tendons, and ligamentsPassages for nerves and blood vesselsCategories of bone markingsProjections and processes grow out from the bone surfaceDepressions or cavities indentations

  • Microscopic Anatomy of BoneOsteon (Haversian System)A unit of boneCentral (Haversian) canalOpening in the center of an osteonCarries blood vessels and nervesPerforating (Volkmans) canalCanal perpendicular to the central canalCarries blood vessels and nerves

  • Microscopic Anatomy of BoneFigure 5.3

  • Microscopic Anatomy of BoneLacunaeCavities containing bone cells (osteocytes)Arranged in concentric ringsLamellaeRings around the central canalSites of lacunaeFigure 5.3

  • Microscopic Anatomy of BoneCanaliculi Tiny canalsRadiate from the central canal to lacunaeForm a transport systemFigure 5.3

  • Changes in the Human SkeletonIn embryos, the skeleton is primarily hyaline cartilageDuring development, much of this cartilage is replaced by boneCartilage remains in isolated areasBridge of the noseParts of ribsJoints

  • Bone GrowthEpiphyseal plates allow for growth of long bone during childhoodNew cartilage is continuously formedOlder cartilage becomes ossifiedCartilage is broken downBone replaces cartilage

  • Bone GrowthBones are remodeled and lengthened until growth stopsBones change shape somewhatBones grow in width

  • Long Bone Formation and GrowthFigure 5.4a

  • Long Bone Formation and GrowthFigure 5.4b

  • Types of Bone CellsOsteocytesMature bone cellsOsteoblastsBone-forming cellsOsteoclastsBone-destroying cellsBreak down bone matrix for remodeling and release of calciumBone remodeling is a process by both osteoblasts and osteoclasts