Anatomy unit 7 physiology of the skeletal system


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Anatomy unit 7 physiology of the skeletal system

  1. 1. Anatomy and Physiology I Unit 7: The Skeletal SystemPhysiology of the Skeletal System
  2. 2. Skeletal System• Bones are made of several tissues• Primarily made of collagen and hydroxyapatite - Ca10(PO4)6(OH)2• About 206 bones in the human body
  3. 3. Functions of Skeletal System• SUPPORT: Hard framework that supports and anchors the soft organs of the body.• PROTECTION: Surrounds organs such as the brain and spinal cord.• MOVEMENT: Allows for muscle attachment therefore the bones are used as levers.• STORAGE: Minerals and lipids are stored within bone material.• BLOOD CELL FORMATION: The bone marrow is responsible for blood cell production.
  4. 4. Parts of the Skeletal System• Axial skeleton – Skull and bones that support it – Includes vertebra and ribs – 80 bones• Appendicular skeleton – Limbs – 126 bones
  5. 5. Features of a Long Bone:Epiphysis: Ends of thebone.Diaphysis: The shaft ofthe bone which surroundsthe medullary cavity.Articular Cartilage:Cushions the ends of thebones and allows forsmooth movement.Epiphyseal Plate:Areas made of cartilageallowing for the growth ofthe bone.
  6. 6. Joints• Where bone meets bone• Ligament – holds bone to bone• Types of joints: – Immovable - skull – Ball-and-socket - shoulder – Hinge - knee – Pivot – forearm – Gliding - vertebrae
  7. 7. Joints• Cartilage covers ends of movable bones – Reduces friction• Lubricated by fluid from capillaries
  8. 8. Cartilage
  9. 9. Bone Structure• Periosteum – hard outer covering – Cells for growth and repair• Compact bone – hard strong layer – Bone cells, blood vessels, protein with Ca and P• Spongy bone – at ends of long bones – Has small open spaces to lighten weight• Marrow cavity – hollow in middle of long bones
  10. 10. Bone Marrow• Red marrow – produces blood cells and clotting factors – Found in humerus, femur, sternum, ribs, vertebrae, pelvis – Produces RBC 2 million per second• Yellow marrow – stores fat – Found in many bones
  11. 11. Bone Structure
  12. 12. Haversian System• Structure of compact bone• Rings of bone tissue with blood vessels and nerves in the center
  13. 13. Haversian System
  14. 14. Bone Development• Initial skeleton of cartilage in infants• Replaced with bone by osteoblasts• More than 300 bones at birth – fuse to 206• Always growing and breaking down – Osteoblasts – form new bone cells – Osteoclasts – break bone cells down – Osteocytes – mature bone cells
  15. 15. Broken Bones• Fracture is a break of the bone• Simple or Complex fracture• Regrowth of bone: – Spongy bone forms in first few days – Blood vessels regrow and spongy bone hardens – Full healing takes 1-2 months
  16. 16. Homeostatic Imbalances Rickets•Disease of children due to a lack of vitamin D.•Calcium is not deposited in bones.•Bones become soft.•Bowing of the bones, and other deformities occur.
  17. 17. Homeostatic Imbalances Osteomalacia •“Rickets” of adults. •Due to a lack of vitamin D. •Calcium is not deposited in the bones. •Bones become brittle.
  18. 18. Homeostatic Imbalances Osteoporosis•Bone reabsorption is greater than bone deposition.•Due to any of the following: •Lack of estrogen in women. •Lack of exercise to stress the bones. •Inadequate intake of calcium and phosphorus. •Abnormalities of vitamin D metabolism. •Loss of muscle mass.
  19. 19. Age Related DysfunctionsArthritis:Osteoarthritis- 90% of pop. By age 40 chronic inflammation of articular cartilage can be normal age-dependent change can also be pathology due to ? Age-related changes decrease blood supply trauma
  20. 20. Osteoarthritis
  21. 21. OsteoporosisDecline in Bone Density Bone Resorption > Bone DepositionIncrease Risk for Fracture compression fractures of vertebrae hip fracturesRole of calcium, vitamin D, estrogen, exercise Calcitonin vs. Parathyroid Hormone
  22. 22. Osteoporosis