EST

• Function of the skeleton


  • Protection of vital organs
  • Movement
  • Fat and mineral storage
  • Blood cell formation
  • Support of the body
• Parts of the human skeleton


  • Axial skeleton (skull, vertebral column)
  • Appendicular skeleton (bones of limbs, bones of shoulder, pelvis)
• Axial skeleton


  Usually 80 bones, lie around the central axis of the body, provides support and protection
• Appendicular skeleton


  Usually 126 bones, provides surface for attachment of the skeletal muscle to provide movement
• Bones in the human arm


  • Clavicle
  • Scapula
  • Humerus
  • Ulna
  • Radius
  • Carpals, metacarpals, phalanges
• Regions of the spine


  • Cervical vertebrae (C1 to C7)
  • Thoracic vertebrae (T1 to T12)
  • Lumbar vertebrae (L1 to L5)
  • Sacrum (S1 to S5)
  • Coccyx
• Classifications of bones


  • Long bones
  • Short bones
  • Flat bones
  • Irregular bones
  • Sesamoid bones
• Long bones


  Elongated shape, with a diaphysis and two epiphysis, function is supporting weight and facilitating movements
• Short bones


  Roughly cubed shaped, function is providing stability and support while allowing limited movement
• Flat bones


  Thin and flattened shape, function is offering protection and providing a large surface area for muscles
• Irregular bones


  Complex shape that doesn't fit into any other classification, function is protection and support
• Sesamoid bones


  Small round bones, embedded in tendons, function is to reduce friction and alter the direction of the pull of the muscle
• Components of a long bone


  • Epiphysis
  • Diaphysis
  • Cancellous bone
  • Compact bone
  • Medullary cavity
  • Yellow bone marrow
  • Red bone marrow
  • Articular cartilage
  • Periosteum
• Proximal


  The end of the bone closer to the body's centre
• Distal


  The end of the bone attached to the knee
• Bone cells


  • Osteocytes
  • Osteoblasts
  • Osteoclasts
• Osteocytes


  Mature bone cells, maintain bone and exchange nutrients and waste
• Osteoblasts


  Bone forming cells for bone growth and secrete bone matrix
• Osteoclasts


  Bone destroying cells, break down bone matrix for remodelling and calcium release
• Microscopic structure of compact bone


  • Osteons or Haversian systems
  • Lamellae
  • Lacunae
• Microscopic structure of cancellous bone


  Thin columns of bone called trabeculae, to help reduce bone stress
• Long bone growth


  1. Formation of cartilage

  2. Ossification

  3. Epiphyseal plates (growth plates)

  4. Growth in length

  5. End of growth
• Epiphyseal plates


  Located at the end of the long bones, consisting of cartilage cells that are actively dividing
• How long bones repair


  1. Blood clots (hematoma) around dead bone cells

  2. Soft callus forms

  3. Hard callus forms

  4. Bone is remodelled
• Types of bone breaks


  • Closed (simple fracture)
  • Open (compound fracture)
• Types of joints


  • Fixed (fibrous)
  • Cartilaginous
  • Synovial
• Types of synovial joints


  • Ball and socket
  • Hinge
  • Pivot
  • Gliding
  • Condyloid
  • Saddle
• Ball and socket joint


  Allows joint to rotate in all directions allowing for a lot of flexibility and range of motion
• Hinge joint


  Can bend and straighten, but can't rotate, therefore restricted to flexion and extension
• Pivot joint


  Allows for rotational movement
• Gliding joint


  Allows movement in side to side and back and forth motions, restricted by ligaments or bony process
• Condyloid joint


  Biaxial joint (allows movement along 2 planes); allows flexion/extension, abduction/adduction, and circumlocution movements
• Saddle joint


  Biaxial joint; allows flexion/extension, abduction/adduction, and circumduction movements
• Components of a synovial joint


  • Muscles
  • Tendons
  • Ligaments
  • Articular cartilage
  • Joint capsule
  • Synovial membrane
  • Synovial fluid
• Tendons


  Connects muscle to bone, strong fibrous and tough connective tissue, inelastic
• Ligaments


  Connects bone to bone, helps keeps bone in place to prevent dislocation, short band of fibrous, flexible, elastic, connective tissue
• Articular cartilage


  Provides a smooth surface to reduce friction, shock absorber, strong tissue that covers the surface of the bones where the joints meet
• Joint capsule


  Provides flexibility and strength to resist dislocation, connected to periosteum of the bones
• Synovial membrane


  Provides nourishment for cells of the articular cartilage, loose connective tissue, secretes synovial fluid which lubricates joints
• Synovial fluid


  Reduces friction between moving bone, shock absorber, exchanges nutrients and waste within the membrane