SKELETAL SYSTEM OVERVIEW

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SKELETAL SYSTEM OVERVIEW
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FUNCTIONS

• Support
• Protection
• Movement-levers
• Storage-lipids, Ca, P
• Formation of blood cells-hematopoiesis

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STRUCTURE

• Two Divisions
• Axial
• Appendicular

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BONE MARKINGS

• Two Categories
• Processes/projections
• Depressions/cavities

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LONG BONE

• Gross anatomy
• Microscopic anatomy
• Bone formation
• Bone fractures

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COMPOSITION

• Lacunae-spaces containing osteocytes
• Lamellae-rings of hard, calcified substance
• Haversian canals-run longitudinally in bone
• Canaliculi-small canals that contain osteocytes

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COMPOSITION, cont

• Volkmanns canals-blood vessels, nerves (from
  periosteum), enter compact bone area which is
  connected to medullary canals

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GROWTH

• Epiphyseal plate provides for long growth during
  childhood
• New cartilage formed continuously and old
  cartilage broken down at same time
• Controlled by hormones
• Ends at end of adolescence because epiphyseal
  plate is converted to bone

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REMODELING

• Old bone destroyed by osteoclasts
• New bone made by osteoblasts
• Stress of muscle pull and gravity determines what
  bones formed or were broken down
• Bedridden people lose bone mass and subjected to
  stress

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BONE FORMATION and GROWTH

• Begins 7th week in utero
• 2 kinds
• Intramembranous-replacing preexisting connective
  tissue with bone
• hyaline membrane covered with bony matrix
  by osteoblasts
• Endochondrial-ossification

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ENDOCHONDRIAL

• Occurs in most bones
• In diaphysis, cartilage degenerates, leaving
  cavities?marrow cavities
• Osteoblasts lay down bone
• Ossification occurs in epiphysis, where bone
  replaces cartilage, except plate
• Low Ca levels cause change on PTH, causing
  osteoclasts to destroy bone cells

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FRACTURES

• Compound
• Simple
• Compression
• Depressed
• Impacted
• Spiral
• Greenstick

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TREATMENT of FRACTURES

• Reduction-realignment of ends
• Closed-Dr., by hand
• Open-surgery, pins, wire

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JOINTS AND ARTICULATIONS

• Position of bony parts is changed
• Occurs at the joints
• Less movement at closer fittings of bones

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CLASSIFICATION

• Synarthroses-no movement skull, sternum, sacrum
• Amphiarthroses-little movement vertebral column,
  rib cage, axial skeleton
• Diarthroses-movement
• synovial joint-ball/socket, hinge, pivot,
  sliding

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Disorders of the Joints Arthritis

• Osteoarthritis- chronic, degenerative, affects
  articular cartilage of the aged (wear and tear
  arthritis)? exposes bone tissue
• Rheumatoid arthritis-chronic, autoimmune, joints
  swell as synovial fluid accumulates, WBC enter
  and produce pannus that erodes articular
  cartilage? scar tissue which ossifies and bone
  ends fuse onset usually 30-40 years of age

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Arthritis
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GOUT
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ARTHRITIS, cont

• Gout- uric acid accumulates in the blood and
  depositied in joints, affects single joint
  common in males, after age 30 (can lead to
  immobilization of joint)

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OSTEOPOROSIS