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Skeletal System

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  1. Skeletal System

  2. Components - Cartilage - Bone - Joints - Ligaments (bone to bone) - Tendons (muscle to bone)

  3. Functions - Support - Movement - Protection - Mineral storage - Blood cell synthesis - hematopoiesis

  4. Cartilage • Hyaline • Elastic • Fibrocartilage

  5. Hyaline cartilage - Articular cartilage – covers ends of bones and moveable joints - Costal cartilage – attach ribs to the sternum - Respiratory cartilage – forms respiratory passages and larynx - Nasal cartilage – forms external nose

  6. Articular cartilage

  7. Costal cartilage

  8. Respiratory cartilage

  9. Nasal cartilage

  10. Elastic cartilage - Forms external ear - Forms epiglottis

  11. Elastic cartilage

  12. Fibrocartilage Withstands heavy pressure & tensile forces - Intervertebral disks - Knees and elbows

  13. Fibrocartilage

  14. Bone • Cell, tissue, organ • Skeleton – Greek for dried up body • Composed of 206 bones 1.Axial skeleton – 80 bones 2.Appendicular skeleton – 126 bones

  15. Classification of bone • Long bones • Short bones • Sesamoid bones • Flat bones • Irregular bones

  16. Long bones - Diaphysis – shaft - Epiphysis – ends of bone; contain red marrow - Medullary cavity – contains yellow marrow - Epiphyseal plate – found between diaphysis and epiphysis; long bone growth

  17. Short bones • Roughly cuboidal in shape

  18. Sesamoid bones form within a tendon e.g. patella

  19. Flat bones Thin, flattened, and slightly curved Diploe – spongy bone found between compact bone layers

  20. Diploe

  21. Irregular bones • complicated shapes e.g. vertebrae, pelvis

  22. Bone cells • Osteoclast – cells which dissolve bone (puts calcium into the blood for muscular contraction, nerve transmission, blood clotting, etc…) • Osteoblast – cells which build bone by removing calcium and phosphates from the blood in the presence of the enzyme alkaline phosphatase secreted by osteoblasts • Osteocyte – mature cells found within compact bone (living bone)

  23. Bone remodeling Occurs under the periosteum (White, double layered membrane) which is held to bone by Sharpey’s fibers

  24. Osseous tissue • Compact bone (Lamellar bone) – Dense and hard; found on the external surfaces of bones • Spongy bone - contain trabeculae (little beams) which align along lines of stress; and open spaces filled with red or yellow marrow

  25. Compact bone = Lamellar bone

  26. Lamellar bone Osteon or Haversian System – structural unit of compact bone (cylindrical in shape) which bear weight - Lamella –each ring of an osteon - Haversian canal – contains blood vessels & nerve fibers which travel vertically in bone -Volkmann’s canal – contain blood vessels and nerve fibers which travel horizontally in bone

  27. Lamellar bone • Lacuna – spaces found in compact bone occupied by osteocytes - Canaliculi – lateral canals which connect lacunae which allow osteocytes to diffuse nutrients and wastes into or out of bone tissue through gap junctions

  28. Spongy bone = Trabecular bone

  29. Chemical composition - Hydroxyapatites 60-70% of bone weight mineral salts; mainly calcium phosphates *source of stiffness and compressive strength - Collagen fibers~ 10% of bone weight made up of glycoproteins *source of flexibility & tensile strength Aging causes decrease in collagen & an increase in fragility - Water~ 25-30% important contributor to bone strength

  30. Bone markings Sites of tendon and ligament attachment Projections that help form joints Depressions and openings allowing blood vessels and nerve fibers to pass

  31. Sites of muscle and ligament attachment - Tuberosity – large rounded projection - Crest – narrow prominent ridge - Trochanter – large, blunt, irregularly shaped process (Only found on the femur)

  32. Sites of muscle and ligament attachment • Tubercle – small rounded projection or process - Epicondyle – raised area above a condyle - Spine – sharp, slender, often pointed projection - Process – any bony prominence

  33. Tuberosity

  34. Crest

  35. Trochanter

  36. Tubercle

  37. Epicondyle

  38. Spine

  39. Process

  40. Projections that help form joints - Head – bony expansion carried on a narrow neck - Condyle – rounded articular projection - Ramus – arm like bar of bone

  41. Head

  42. Condyle

  43. Ramus