1.  The Skeletal System

2. Parts of the skeletal system

4. Two subdivisions of the skeleton  Axial skeleton  Appendicular skeleton

5. Two subdivisions of the skeleton

6.  Adult skeleton approximately 206 bones  Axial: 80 bones  Appendicular: 126 bones

7. Two basic types of bone tissue  Compact bone  Homogeneous  Spongy bone  Many open spaces

8. Classification of Bones based on Shape

17. Anatomy of a Long Bone  Epiphysis

18. Anatomy of a Long Bone

19.  Diaphysis

20. Anatomy of a Long Bone  Periosteum  Sharpey ’ s fibers  Arteries

21. Anatomy of a Long Bone

23.  Articular cartilage  Covers surface of the epiphyses

24. Anatomy of a Long Bone  Epiphyseal plate  Epiphyseal line

25. Anatomy of a Long Bone

27.  Medullary cavity  Cavity inside of the shaft

29. Bone Markings  Are bones smooth surfaces?  Femur

30.  Are bones smooth surfaces?  Tibia

31. Bone Markings  Are bones smooth surfaces?  Mandible

32. Bone Markings  Are bones smooth surfaces?  Optical canal

33. Compact vs. Spongy bone

34. Microscopic Anatomy of Compact Bone  Osteocytes: mature bone cells  Lacunae:

35. Microscopic Anatomy of Compact Bone  Lamella:

36. Microscopic Anatomy of Compact Bone  Central (Haverersian) Canals:

37. Microscopic Anatomy of Compact Bone  Osteon (Haversian System):

38. Microscopic Anatomy of Compact Bone

39.  Canaliculi:  Hint: which way do central canals run?

40. Microscopic Anatomy of Compact Bone

41.  This eleaborate network of canals ensures bone cells are well nourished  What significance does this have?

42.  Perforating (Volkmann’s) canals:

44. Microscopic Anatomy of Compact Bone

46. Bone Formation, Growth, & Remodeling  Mostly hyaline cartilage  Replaced by bone

47. Bone Formation, Growth, & Remodeling Bone starting to replace cartilage Epiphyseal plate cartilage Articular cartilage Spongy bone In a childIn a fetusIn an embryo New bone forming Growth in bone width Growth in bone length Epiphyseal plate cartilage New bone forming Blood vessels Hyaline cartilage New center of bone growth Medullary cavity Bone collar Hyaline cartilage model (a)

48. Bone Formation, Growth, & Remodeling  Osteocytes—mature bone cells  Osteoblasts—bone-forming cells  Osteoclasts—bone-destroying cells

49. Growth & Remodeling  New cartilage is continuously formed  Older cartilage becomes ossified

50. Growth & Remodeling  Osteocytes can sense areas of stress  Enhances the process  Balance of calcium levels

51. Fractures

57.  Treated by Reduction:  Closed  Open