1. THE SKELETAL SYSTEM

2. I. BONE STRUCTURE & FUNCTION A.FUNCTION 1.Support 2.Protection 3.Movement 4.Blood formation 5.Electrolyte Balance 6.Acid Base Balance

3. I. BONE STRUCTURE & FUNCTION B.Structure 1.Shape –Long bones –Short bones –Flat bones –Irregular bones

4. Long bonesShort bones

5. Flat bones Irregular bones

6. Classify the bone types to the left

7. B. Structure 2. Parts of Bone –Epiphyses Contains red bone marrow Spongy bone and compact bone

8. B.Structure 2.Parts of Bone –Diaphysis Shaft of bone Contains yellow bone marrow (stores fat) Spongy and compact bone

10. B.Structure 2.Parts of Bone –Periosteum –Epiphyseal plate  Allows for growth in bone  Found only in children

11. 3.Mature Bone Osseous Tissue B. Structure

12. Lamellar bone Called Lamellar bone Two kinds  Compact  Spongy (cancellous) 3. Mature Bone

13. Spongy (cancellous) contains trabeculae contains trabeculae contains spaces contains spaces 3. Mature Bone

14. Dense, few spaces Dense, few spaces Haversian canals Haversian canals Concentric Lamellae Concentric Lamellae Compact Bone 3. Mature Bone

15. I. BONE STRUCTURE & FUNCTION Background minerals C.Histology 1.Matrix

17. C. Histology 2.Bone cells

18. Osteoblasts

19. Osteocytes Osteoclasts

20. Osteoblasts Osteoclasts Osteocytes

21. Name C, D & E D = Osteoblast E = Osteocytes C = Osteoclast

22. D. Membranes 1.Periosteum 1.Periosteum: a.The external covering of bone

23. D. Membranes 2.endosteum: a.Found on internal bone surface b.covers trabeculae of spongy bone c.in marrow cavities

25. II. BONE GROWTH & DEVELOPMENT A.Two Patterns of Bone Formation 1.Intramembranous bones –originate between sheet-like layers of connective tissues

26. II. BONE GROWTH & DEVELOPMENT A.Two Patterns of Bone Formation 2.Endochondral bones –begin as masses of hyaline cartilage that bone tissue later replaces.

27. II. BONE GROWTH & DEVELOPMENT B.Growth in Long Bones 1.grow by interstitial growth at epiphyseal plates a.rate of cartilage growth is balanced by replacement with bone b.end of growth as cartilage cells slow down division

28. II. BONE GROWTH & DEVELOPMENT B.Growth in Long Bones 2. bones grow in width by appositional growth a.Osteoblasts in periosteum: secretes bone matrix b.Osteoclasts in endosteum: removes bone matrix (a little slower)

29. Appositional Growth –New bone forms at ridges around blood vessels –Periosteum becomes endosteum

30. – New lamella formed – More bone added forming osteon Appositional Growth

31. II. BONE GROWTH & DEVELOPMENT C.Hormones 1. growth hormone from pituitary: stimulates growth in childhood a.Gigantism: excessive growth hormone b.dwarfism: not enough growth hormone or thyroid hormones

32. II. BONE GROWTH & DEVELOPMENT C.Hormones 2. thyroid: regulates activity of growth hormone 3. sex hormones: promote growth spurt, induce epiphyseal plate closure estrogen: maintains bone density

33. III. Bone Maintenance & Repair A.Bone remodeling: 1.Life long process 2. Local areas of bone are destroyed and rebuilt 3. Repairs microdamage caused by normal wear and tear

35. B.Fractures 1. Simple 1. Simple bone breaks cleanly, does not break through skin

36. B.Fractures 2. Compound 2. Compound broken ends protrude through the skin, risk of bone infection

37. B.Fractures 3. Greenstick 3. Greenstick Greenstick: (children) Does not break completely

44. C. Repair Hematoma forms 1. Hematoma forms 2. Spongy bone forms in area of hematoma 2. Spongy bone forms in area of hematoma III. Remodeling and Repair

45. C. Repair Osteoblasts lay down new bone matrix 3. Osteoblasts lay down new bone matrix 4. Remodeling 4. Remodeling

46. III. Calcium Homeostasis A.Blood Ca 2+ Level 1.Has a very narrow range 2. Ca 2+ Required for –For normal muscle contraction –Nerve impulses

47. III. Calcium Homeostasis A.Blood Ca 2+ Level 3.Abnormal levels –Hypocalcemia causes marked jitteriness and convulsive seizures

48. III. Calcium Homeostasis A.Blood Ca 2+ Level 3.Abnormal levels –Hypercalcemia the most common life- threatening metabolic disorder associated with cancer

49. III. Calcium Homeostasis B.Bone’s Role 1.Major storage site for calcium 2.Calcium moves –Into bone as osteoblasts build new bone –Out of bone as osteoclasts break down bone

50. III. Calcium Homeostasis C.Bone, Calcium and Hormones 1.Parathyroid Hormone – Increases blood Ca 2+ levels 2.Calcitonin Decreases blood Ca 2+ levels

51. D. Homeostatic Imbalances OsteopeniaOsteopenia – Inadequate ossification OsteoporosisOsteoporosis – Bone absorption outpaces deposition – Fractures common – More common in elderly women III. Calcium Homeostasis

52. RicketsRickets – Lack of vitamin D or calcium during growth – Bowed legs – Deformed pelvis D. Homeostatic Imbalances Rickets

53. Osteosarcoma – Bone cancer – Usually between ages 10-25 – Survival rate is about 50% with amputation D. Homeostatic Imbalances

54. Bone spurBone spur – Abnormal projection at one site of bone due to overgrowth – Common in aging bones D. Homeostatic Imbalances

55. IV. The Skeleton There are 206 bone

56. IV. The Skeleton A.Organization 1.Axial Skeleton –Skull –Vertebral Column –Vertebrae –Ribs 2.Appendicular Skeleton –limbs –girdles

57. B. Male vs. Female Skeleton - Pelvis a.spines farther apart in male b.hole in ischium: smaller and triangular in female c.angle across pubic symphysis = pubic arch: less than 90° and more sharply angled in male d.distance between ischia larger in female

58. C.Bone Markings – 1. Kinds

59. For muscle attachment For formation of a joint To allow blood vessels or nerves to pass through Articulating Surfaces Openings Depressions & Enlargements 1. Kinds

60. C.Bone Markings – 2. Articulating surfaces A rounded projection set off from the body of a bone by a constriction (the neck) ex. head of femur Head

61. C.Bone Markings – 2. Articulating surfaces Condyle Any large articulating surface, may be concave or convex

62. C.Bone Markings – 2. Articulating surfaces A smooth, flat surface, generally small Facet

63. C.Bone Markings – 2. Articulating surfaces A shallow depression Fossa

64. C.Bone Markings – 3. Enlargements & Processes generic term for bone projection that serves as a point for attachment of other structures Process

65. C.Bone Markings – 3. Enlargements projection or swelling to the side of or above a condyle Epicondyle

66. C.Bone Markings – Spine a sharp, slender projecting process 3. Enlargements

67. C.Bone Markings – a small rounded projection Tubercle 3. Enlargements

68. C.Bone Markings – a large rounded roughened projection 3. Enlargements Turberosity

69. C.Bone Markings – 3. Enlargements Trochanter a large blunt projection

70. C.Bone Markings – 3. Enlargements a prominent border or ridge Crest

71. C.Bone Markings – 3. Enlargements A major branch or division off of the main body of a bone Ramus

72. C.Bone Markings – 4. Openings

73. C.Bone Markings – 4. Openings Canal like opening Meatus

74. C.Bone Markings – 5. Depressions A shallow groove Sulcus

75. C.Bone Markings – 5. Depressions A very shallow groove Fovea

76. C.Bone Markings – 5. Depressions A deep groove Fissure

77. That’s All Folks!