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Skeletal System Skeletal System Chapter

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					Skeletal System
    Chapter 5
      Components of the Skeletal
              System
   Skeleton subdivided
    – Axial Skeleton-longitudinal
      axis of body
    – Appendicular Skeleton-
      limbs and girdles


   Skeletal System includes
    – Joints – 3 types
    – Cartilages – 3 types
         Hyaline, Fibrocartilage,
          Elastic
    – Ligaments – bone to bone


                                     http://www.daviddarling.info/encyclopedia/S/skeleton.html
            Functions of Bones
   Support: framework
   Protection: protect soft body organs
    examples?
   Movement: skeletal muscles attached to bones
    via tendons
   Storage: fats in the internal cavities of bones
    and minerals such as Ca++ and Phosphorus.
   Blood cell formation: hematopoiesis (blood cell
    formation) – marrow cavities of some bones.
         Classification of Bones
   Two types of osseous
    tissue
    – Compact bone-dense,
      smooth, homogeneous
    – Spongy bone-
      needlelike pieces of
      bone and lots of open
      space.


            http://www.britannica.com/EBchecked/topic-art/276196/101316/Longitudinal-section-of-the-humerus-showing-outer-compact-bone-and
Classification based on Shape
                                                      Four groups
                                                       1) Long bones – longer than wide,
                                                       shaft with heads at both ends,
                                                       mostly compact bone, all bones of
                                                       limbs except patella, wrist, ankle

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

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

                                                       4) Irregular bones – don’t fit
 http://www.aclasta.co.nz/osteoporosis/index.htm
                                                       previous categories, hip bones,
                                                       vertebrae
           Structure of a Long Bone
   Diaphysis - shaft
   Periosteum - fibrous connective
    tissue membrane
   Endosteum
   Sharpey’s fibers - perforating fibers
    connect periosteum to bone
   Epiphyses - ends, compact bone
    enclosing spongy
   Articular cartilage - covers
    epiphyses, glassy hyaline cartilage-
    decreases friction
   Epiphyseal line - adult bones,
    epiphyseal plate in growing bones,
    hyaline cartilage, growth, replaced
    by bone in puberty                      http://www.curehandpain.com/images/bone/long_bone.gif
        Structure of a Long Bone

   Medullary cavity –
   1) adults - yellow marrow
    2) infants – red marrow
    - in adults red marrow
    confined to spongy bone of
    flat bones and epiphyses of
    some long bones
   Bone Markings – Table 5.1
    projections vs depressions
    ex. Trochanter, Foramen
                                  http://www.curehandpain.com/images/bone/long_bone.gif
   Microscopic Anatomy of Long
               Bone
                                                              Osteocytes – mature
                                                               bone cells
                                                              Lacunae – cavities where
                                                               osteocytes found
                                                              Lamellae – circles lacunae
                                                               found
                                                              Haversian canals – center
                                                               of lamellae
                                                              Osteon – lamellae +
                                                               Haversian canal
                                                              Canaliculi
                                                              Volkmann’s canals



http://www.octc.kctcs.edu/GCaplan/anat/images/Image269.gif
    Microscopic Anatomy of Long
                Bone
 Osteocytes – mature
  bone cells
 Lacunae – cavities where
  osteocytes found
 Lamellae – circles lacunae
  found
 Haversian canals – center
  of lamellae
 Osteon – lamellae +
  Haversian canal
 Canaliculi
 Volkmann’s canals



             http://education.vetmed.vt.edu/curriculum/vm8054/labs/Lab8/IMAGES/OSTEON%20AND%20INTERSTITIAL%20SYSTEM.jpg
    Bone Formation, Growth, and
            Remodeling
 Skeleton formed
  from bone and
  cartilage
 Embryos vs young
  children
 Cartilage remains in
  nose, parts of ribs,
  joints
 Ossification – bone
  formation
                         http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg
                   Ossification

 Ossification – 2 phases
  1) Hyaline cartilage model
  covered w/ bone matrix by
  Osteoblasts
  2) Cartilage digested
  opening Medullary cavity
-By birth hyaline cartilage
  models coverted to bone
  except articular cartilages
  and epiphyseal plates
                                http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg
              Bone Growth - Lengthening

                                                            New cartilage added 2 places
                                                             – external articular cartilage
                                                             and ephiphyseal plate
                                                            What do each of these do?
                                                            Old cartilage digested replaced
                                                             by bony matrix



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

 Appositional Growth –
  diameter increase
 Osteoblasts in periosteum add
  bone tissues to diaphysis
 Osteoclasts in endosteum
  remove bone from inner
  diaphysis
 Occurs at about same rate
 Controlled by hormones
 Ends in puberty – epiphyseal
  plates converted to bone
                           http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg
             Bone Remodeling
   2 Factors
    1) Ca++ in blood – bones as storage
        a) below homeostatic levels
        – parathyroid glands release PTH into
        blood.
        - PTH activates osteoclasts
        b) above homeostatic levels
        - Ca++ deposited as calcium salts
            Bone Remodeling

2) pull of gravity and muscles on bone
 Necessary to retain proportions and strength during
   growth
 Bones become thicker and form projections where
   bulky muscles attached
 No stress – bones weaken and atrophy


   Ca++ uptake/release and remodeling work together
    – PTH determines WHEN bone broken down or deposited based
      on [Ca++] in blood
    – Muscle pull and gravity determine WHERE bone broken down
      or deposited
                  Bone Fractures
   Occur less often in youth,
    requires exceptional trauma
    – twists or smashes
   Two types – simple or
    compound
    – Comminuted – many fragments
    – Compression – crushed
    – Depressed – broken bone
      portion pressed inward (skull)                http://www.hivandhepatitis.com/2008icr/ddw/docs/060308_b.html



    – Impacted – broken ends forced
      into each other
    – Spiral – ragged break due to
      twisting
    – Greenstick – incomplete break


                                http://www.itim.nsw.gov.au/index.cfm?objectid=2A54AE6D-1321-1C29-707811D2028CC580
                         Bone Repair
    Reduction – closed or open,
     immobilization to all healing
1)   Hematoma forms – blood
     vessels broken, blood filled
     swelling
2)   Fibrocartilage callus formation –
     mass of repair tissue – cartilage
     matrix, bony matrix, and
     collagen fibers, act as splint
3)   Bony Callus forms – osteoblasts
     and osteoclasts migrate to
     break, spongy bone callus forms
4)   Bone Remodeling – permanent
     patch due to stresses




                            http://1.bp.blogspot.com/_57e2KV2nOZs/SAGetjS3TjI/AAAAAAAAAY8/rvhaSyEf-us/s400/bone+repair.jpg
                  Axial Skeleton
                  Bones of Skull
   Cranium + facial
   Cranium – encloses
    brain tissue
   Facial – hold eyes,
    facial expressions
   Joined by sutures –
    immovable joints
   1 exception – what is
    it?
                            http://commons.wikimedia.org/wiki/File:Human_skull_side_simplified_(bones).svg
               Cranium Bones
   Frontal – forehead
   Parietal – most of
    cranium, sagittal
    suture
   Temporal – around
    ear, squamous suture
   Occipital – floor and
    back, lambdoid suture
   Sphenoid – butterfly
    shaped

                            http://commons.wikimedia.org/wiki/File:Human_skull_side_simplified_(bones).svg
       Facial Bones and Damage



                                                                                       http://www.peidental.ca/cleft.html
                                                         Cleft Palate – incomplete Maxillae
                                                         formation




http://www.physioweb.org/skeletal/skeletal_struct.html

                                                                http://www.cdc.gov/ncbddd/BD/cleft.htm
              Infant vs Adult Skull
   Infant
    – Face small to cranium
    – Cranium ¼ body length
    – Fibrous regions – fontanels   http://www.waukesha.uwc.edu/lib/reserves/pdf/zillgitt/zoo170/diagra
                                    ms2/diagrams2.html
      allow compression, brain
      growth
   Adult
    – Completely ossified
    – Fused at sutures
    – 1/8 body length
             Vertebral Column
   Axial Support of body
   Skull to pelvis
   26 vertebrae (which type?)
    connected and reinforced by
    ligaments
   Protects spinal cord
   Before birth 33 vertebrae
   Separated by fibrocartilage –
    intervertebral discs
                            http://commons.wikimedia.org/wiki/File:Gray_111_-_Vertebral_column-coloured.png
                                        Vertebral Column
                                                                                         Discs and S-shape
                                                                                          prevent shock to head
                                                                                          and make trunk flexible
                                                                                         Primary curvatures –
                                                                                          thoracic and sacral
                                                                                          regions
                                                                                          – Make C-shape of newborn
                                                                                         Secondary curvatures –
                         http://www.sleepywrap.com/index.php?page=stroller-baby-carrier
                                                                                          cervical and lumbar
                                                                                          – Develop after birth
                                                                                          – Allow to center weight
http://commons.wikimedia.org/wiki/File:Gray_111_-_Vertebral_column-coloured.png
              Herniated Discs
                                               http://www.cedars-sinai.edu/5274.html



 Drying of discs,
  weakening of
  ligaments predisposes
  older to problem
 Also caused due to
  exceptional twisting
 Pressure from disc on
  spinal cord or nerves –
  numbness and/or pain

                            http://myhealth.ucsd.edu/library/healthguide/en-us/support/topic.asp?hwid=zm5009
           Abnormal Spine Curvatures
                                                                   Scoliosis, Kyphosis, Lordosis – All are
                                                                   either congenital, result of disease, due
                                                                   to poor posture, or unequal pull of
                                                                   muscles on spine




     http://www.merinews.com/catFull.jsp?articleID=147926




http://www.spineuniverse.com/displayarticle.php/article3094.html
                                                                     http://www.nytimes.com/imagepages/2007/08/01/health/adam/9583Lordosis.html
                Thoracic Cage
 Also known as bony
  thorax
 Protects organs in
  thoracic cavity
 Made up of sternum,
  ribs, and thoracic
  vertebrae
    – What kind of bones
      are these?

                           http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/skeletal.htm
                                      Ribs
   12 pair
   True Ribs – 1st 7 pair
    – Attach to sternum via costal
      cartilages
   False Ribs – last 5 pair
    – Indirectly or not attached to
      sternum
   Floating Ribs – last 2 pair
    – Lack sternal attachment

    Intercostal space – filled with
       intercostal muscle
            Appendicular Skeleton
               Shoulder Girdle
   Consist of 2 bones

    – Clavicle – collar bone

    – Scapula – shoulder
      blades




                               http://www.digitalartform.com/archives/2004/11/anatomy_practic_6.html
                     Upper Limbs
 30 bones
 Arm
    – Humerus
    – Which type of bone?
   Forearm
    – Radius, Ulna
   Hand
    – Carpal (8) wrist
    – Metacarpals (1->5)
    – Phalanges (14)
                            http://commons.wikimedia.org/wiki/File:Human_arm_bones_diagram.svg
                Pelvic Girdle
 Large and heavy
  bones
 Attached to axial
  skeleton
 Bearing weight most
  important function
 Houses reproductive
  organs, urinary
  bladder, part of large
  intestines

                       http://classes.midlandstech.com/bio112/figure7.23pelvic%20girdle%20and%20hip%20bone.htm
                      Lower Limbs
   Thigh
    – Femur – heaviest,
      strongest bone in body
   Leg
    – Tibia, Fibula
   Foot
    –   Tarsals (7)
    –   Metatarsals (5)
    –   Phalanges (14)
    –   Supports weight, level
        to propel bodies         http://www.nlm.nih.gov/medlineplus/ency/imagepages/8844.htm
                                    Joints
   All bones form joint except 1
   2 functions – hold bone
    together, mobility
   Classified 2 ways
     –   Functionally – amount of
         movement
             Synarthroses - immovable
             Amphiarthroses - slightly
             Diarthroses – freely
             Where would you find each?
     –    Structurally – separation of
         body regions at joint
           Fibrous - immovable
           Cartilaginous - both
           Synovial - freely              http://apps.uwhealth.org/health/adam/sp/13/100006.htm
                      Joints

   Cartilaginous – bone ends connected by
    cartilage
    – Intervertebral joints of spine (amphiarthrotic)
    – Epiphyseal plate of growing long bone
      (synarthrotic)
   Fibrous – boned united by fibrous tissue
    – Sutures of cranium, connective tissue
                             Joints
   Types of Synovial
    Joints based on shape
    – Shape determines
      movement
    – Plane, hinge, pivot,
      condyloid, saddle, ball-
      and-socket
   Synovial – bones
    joined by cavity filled
    with synovial fluid
    – All joints of limbs

                            http://www.octc.kctcs.edu/gcaplan/anat/Notes/API%20Notes%20I%20Types%20of%20Joints.htm
       Diseases of the Joints
                                                    Sprains – ligaments,
                                                     tendons damaged,
                                                     heal slowly and
                                                     painful due to low
                                                     blood supply
     http://www.epodiatry.com/ankle-sprain.htm



Arthritis – joint inflammation, 100+ diseases,
most widespread degenerative disease.
      Acute – bacterial infection, Antibiotics
      Chronic – Osteoarthritis, Rheumatoid,
      gouty
                                            Osteoarthritis



                                                                         http://www.csmc.edu/5619.html



                                                                     85% elderly
                                                                     “wear and tear”
                                                                     Articular cartilage
                                                                     Bone spurs –
http://www.yorkshirekneeclinic.co.uk/knee-arthritis-treatment.htm
                                                                      restricted movement
           Rheumatoid Arthritis (RA)



                                                                 http://www.cedars-sinai.edu/5234.html




                                                              Chronic inflam. Disease
                                                              3x women
                                                              Joints of fingers, wrists,
                                                               ankles and feet
                                                              Symmetrical
                                                              Auto-immune
                                                              Cartilage destroyed, scar
http://www.bestglucosamine.co.uk/rheumatoid-arthritis.html
                                                               tissue connect bones, ossifies
             Gouty Arthritis
 Uric acid accumulates
  in blood, deposits
  crystals in joints,
 Normally affects
  single joint             http://gouthomeremedies.info/category/uncategorized



 Mostly men, rarely
  before 30



                          http://www.learningradiology.com/notes/bonenotes/goutpage.htm
The End

				
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