skeletal system - skeleton subdivided ... movement: skeletal muscles attached to bones ... due to...

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  • Skeletal SystemSkeletal SystemChapter 5Chapter 5

  • Components of the Skeletal Components of the Skeletal SystemSystem

    Skeleton subdividedSkeleton subdivided Axial Skeleton-longitudinal Axial Skeleton-longitudinal

    axis of bodyaxis of body Appendicular Skeleton-Appendicular Skeleton-

    limbs and girdleslimbs and girdles

    Skeletal System includesSkeletal System includes Joints 3 typesJoints 3 types Cartilages 3 typesCartilages 3 types

    Hyaline, Fibrocartilage, Hyaline, Fibrocartilage, ElasticElastic

    Ligaments bone to boneLigaments bone to bone

    http://www.daviddarling.info/encyclopedia/S/skeleton.html

  • Functions of BonesFunctions of Bones SupportSupport: framework: framework ProtectionProtection: protect soft body organs: protect soft body organs

    examples?examples? Movement: Movement: skeletal muscles attached to bones skeletal muscles attached to bones

    via tendonsvia tendons StorageStorage: fats in the internal cavities of bones : fats in the internal cavities of bones

    and minerals such as Caand minerals such as Ca++++ and Phosphorus. and Phosphorus. Blood cell formationBlood cell formation: hematopoiesis (blood cell : hematopoiesis (blood cell

    formation) marrow cavities of some bones.formation) marrow cavities of some bones.

  • Classification of BonesClassification of Bones

    Two types of osseous Two types of osseous tissuetissue Compact bone-dense, Compact bone-dense,

    smooth, homogeneoussmooth, homogeneous Spongy bone-Spongy bone-

    needlelike pieces of needlelike pieces of bone and lots of open bone and lots of open space.space.

    http://www.britannica.com/EBchecked/topic-art/276196/101316/Longitudinal-section-of-the-humerus-showing-outer-compact-bone-and

  • Classification based on ShapeClassification based on Shape Four groups Four groups

    1) 1) Long bonesLong bones longer than wide, longer than wide, shaft with heads at both ends, shaft with heads at both ends, mostly compact bone, all bones of mostly compact bone, all bones of limbs except patella, wrist, anklelimbs except patella, wrist, ankle

    2) 2) Short bonesShort bones cube shaped, cube shaped, mostly spongy, wrist, ankle, mostly spongy, wrist, ankle, sesamoid bonessesamoid bones

    3) 3) Flat bonesFlat bones thin, flattened, thin, flattened, usually curved, outer layers of usually curved, outer layers of compact bone sandwich spongy, compact bone sandwich spongy, skull, ribs, sternumskull, ribs, sternum

    4) 4) Irregular bonesIrregular bones dont fit dont fit previous categories, hip bones, previous categories, hip bones, vertebrae vertebrae

    http://www.aclasta.co.nz/osteoporosis/index.htm

  • Structure of a Long BoneStructure of a Long Bone

    Diaphysis Diaphysis - shaft- shaft Periosteum Periosteum - fibrous connective - fibrous connective

    tissue membranetissue membrane EndosteumEndosteum Sharpeys fibers -Sharpeys fibers - perforating fibers perforating fibers

    connect periosteum to boneconnect periosteum to bone Epiphyses Epiphyses - ends, compact bone - ends, compact bone

    enclosing spongyenclosing spongy Articular cartilageArticular cartilage - covers - covers

    epiphyses, glassy hyaline cartilage-epiphyses, glassy hyaline cartilage-decreases frictiondecreases friction

    Epiphyseal lineEpiphyseal line - adult bones, - adult bones, epiphyseal plate in growing bones, epiphyseal plate in growing bones, hyaline cartilage, growth, replaced hyaline cartilage, growth, replaced by bone in pubertyby bone in puberty http://www.curehandpain.com/images/bone/long_bone.gif

    http://www.curehandpain.com/images/bone/long_bone.gif

  • Structure of a Long BoneStructure of a Long Bone

    Medullary cavity Medullary cavity 1) adults - yellow marrow1) adults - yellow marrow

    2) infants red marrow2) infants red marrow- in adults red marrow - in adults red marrow confined to spongy bone of confined to spongy bone of flat bones and epiphyses of flat bones and epiphyses of some long bonessome long bones

    Bone Markings Table 5.1 Bone Markings Table 5.1 projections vs depressionsprojections vs depressionsex. Trochanter, Foramenex. Trochanter, Foramen

    http://www.curehandpain.com/images/bone/long_bone.gif

    http://www.curehandpain.com/images/bone/long_bone.gif

  • Microscopic Anatomy of Long Microscopic Anatomy of Long BoneBone

    Osteocytes mature Osteocytes mature bone cellsbone cells

    Lacunae cavities where Lacunae cavities where osteocytes foundosteocytes found

    Lamellae circles lacunae Lamellae circles lacunae foundfound

    Haversian canals center Haversian canals center of lamellaeof lamellae

    Osteon lamellae + Osteon lamellae + Haversian canalHaversian canal

    CanaliculiCanaliculi Volkmanns canalsVolkmanns canals

    http://www.octc.kctcs.edu/GCaplan/anat/images/Image269.gif

  • Microscopic Anatomy of Long Microscopic Anatomy of Long BoneBone

    Osteocytes mature Osteocytes mature bone cellsbone cells

    Lacunae cavities where Lacunae cavities where osteocytes foundosteocytes found

    Lamellae circles lacunae Lamellae circles lacunae foundfound

    Haversian canals center Haversian canals center of lamellaeof lamellae

    Osteon lamellae + Osteon lamellae + Haversian canalHaversian canal

    CanaliculiCanaliculi Volkmanns canalsVolkmanns canals

    http://education.vetmed.vt.edu/curriculum/vm8054/labs/Lab8/IMAGES/OSTEON%20AND%20INTERSTITIAL%20SYSTEM.jpg

  • Bone Formation, Growth, and Bone Formation, Growth, and RemodelingRemodeling

    Skeleton formed from Skeleton formed from bone and cartilagebone and cartilage

    Embryos vs young Embryos vs young childrenchildren

    Cartilage remains in Cartilage remains in nose, parts of ribs, nose, parts of ribs, jointsjoints

    OssificationOssification bone bone formationformation

    http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg

  • OssificationOssification

    Ossification 2 phasesOssification 2 phases1) Hyaline cartilage model 1) Hyaline cartilage model covered w/ bone matrix by covered w/ bone matrix by OsteoblastsOsteoblasts2) Cartilage digested 2) Cartilage digested opening Medullary cavityopening Medullary cavity

    -By birth hyaline cartilage -By birth hyaline cartilage models coverted to bone models coverted to bone except articular cartilages except articular cartilages and epiphyseal platesand epiphyseal plates

    http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg

  • Bone Growth - LengtheningBone Growth - Lengthening

    New cartilage added 2 places New cartilage added 2 places external articular cartilage external articular cartilage and ephiphyseal plateand ephiphyseal plate

    What do each of these do?What do each of these do? Old cartilage digested replaced Old cartilage digested replaced

    by bony matrixby bony matrix

    http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg

  • Bone Growth - WideningBone Growth - Widening

    Appositional Growth Appositional Growth diameter increasediameter increase

    OsteoblastsOsteoblasts in periosteum add in periosteum add bone tissues to diaphysisbone tissues to diaphysis

    OsteoclastsOsteoclasts in endosteum in endosteum remove bone from inner remove bone from inner diaphysisdiaphysis

    Occurs at about same rateOccurs at about same rate Controlled by hormonesControlled by hormones Ends in puberty epiphyseal Ends in puberty epiphyseal

    plates converted to boneplates converted to bone

    http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg

  • Bone RemodelingBone Remodeling 2 Factors 2 Factors

    1) Ca1) Ca++++ in blood bones as storage in blood bones as storagea) below homeostatic levels a) below homeostatic levels parathyroid glands release PTH into parathyroid glands release PTH into blood.blood.

    - PTH activates osteoclasts- PTH activates osteoclastsb) above homeostatic levels b) above homeostatic levels - Ca- Ca++++ deposited as calcium salts deposited as calcium salts

  • Bone RemodelingBone Remodeling

    2) pull of gravity and muscles on bone2) pull of gravity and muscles on bone Necessary to retain proportions and strength during Necessary to retain proportions and strength during

    growthgrowth Bones become thicker and form projections where Bones become thicker and form projections where

    bulky muscles attachedbulky muscles attached No stress bones weaken and atrophyNo stress bones weaken and atrophy

    CaCa++++ uptake/release and remodeling work together uptake/release and remodeling work together PTH determines WHEN bone broken down or deposited based PTH determines WHEN bone broken down or deposited based

    on [Caon [Ca++++] in blood] in blood Muscle pull and gravity determine WHERE bone broken down Muscle pull and gravity determine WHERE bone broken down

    or deposited or deposited

  • Bone FracturesBone Fractures Occur less often in youth, Occur less often in youth,

    requires exceptional trauma requires exceptional trauma twists or smashes twists or smashes

    Two types simple or Two types simple or compoundcompound Comminuted many fragmentsComminuted many fragments Compression crushedCompression crushed Depressed broken bone Depressed broken bone

    portion pressed inward (skull)portion pressed inward (skull) Impacted broken ends forced Impacted broken ends forced

    into each otherinto each other Spiral ragged break due to Spiral ragged break due to

    twistingtwisting Greenstick incomplete breakGreenstick incom

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