The Skeleton

1. The Skeleton

2. Bone Facts • Living tissue (hard form of connective tissue) • Chief supporting tissue of body • 206 bones • Babies are born with 270 soft bones • 64 of those bones eventually fuse together to make the 206 hard permanent bones that an adult has

3. Male bones tend to be larger and heavier than females • Females pelvic cavity is wider to accommodate childbirth

5. Functions of the Skeleton • Aid in movement of the body • moveable levers which muscles pull to move different parts of the body • To support and protect internal body organs • To produce red and white blood cells • 2.6 million red blood cells produced each second • Replace those worn out and destroyed by the liver • To provide a storehouse for minerals • Calcium and phosphorous • Protective and supportive framework for attached muscles and soft tissues that underlie it

6. Bones • Consist of microscopic cells called osteocytes • Organic Part • Protein called bone collagen – fibrous material • Between fibers is jellylike material • Inorganic Part • Mineral salts • Give bones its hardness and durability • When pressure is applied to a bone: • Flexible organic material prevents bone damage • Mineral elements resist crushing under pressure

7. Bone Structure • Periosteum: outside of the bone • Tough fibrous tissue that contains blood vessels, lymph vessels, and nerves • Necessary for bone growth, repair, and nutrition • Diaphysis • Compact bone • Epiphysis • End of the diaphysis • Contain red marrow where some red blood cells and some white blood cells are made

9. Articular cartilage • Covers epiphysis • Acts as a shock absorber between two bones at a joint. • Endosteum • Lining of the marrow canal to keep the cavity intact • Medullary canal (cavity) • Filled with yellow bone marrow

11. Yellow bone marrow • Mostly fat cells, blood vessels, and white blood cells • Functions as a fat storage center • Spongy bone • where less strength is needed in the bone • Found near the epiphyseal line (growth plate)

14. Bone Formation • Embryonic skeleton consists of collagenous protein fibers • During development the body is made up of mostly hyaline cartilage • During the 8th week, ossification beings and bone starts to replace cartilage • As they ossify they become hard and more capable of bearing weight

15. Bone Growth • Bones grow in length and ossify from the center of the diaphysis towards the epiphyses • Osteoblasts deposit new bone to the outer surface which increases the circumference • Osteoclasts secrete enzymes that digest bony material creating the medullary canal

16. The length of the bone shaft continues to grow until the growth plates are closed • Bone growth ends for females around 18 • Bone growth ends for males around 20-21 • New bone growth can occur in a fractured bone at any time

17. Parts of the Skeleton • Axial Skeleton • 80 bones • Skull, spine, ribs, and sternum

18. Appendicular Skeleton • Made up of the shoulder girdle, pelvic girdle, and limbs • 126 bones • 64 bones in the shoulders and upper limbs • 62 bones in the pelvis and lower limbs

19. Types of Bone • Flat • Thin, flattened, and usually a bit curved • Serve protective function • Scapula, sternum, ribs, most bones of skull • Irregular • Have weird shapes that do not fit other 3 classes • Vertebrae, hip, 2 skull bones (sphenoid, ethmoid bones)

21. Short • Cube-like in shape • Found in carpals (wrist) and tarsals (ankle) • Long • Much longer than they are wide • All bones of limbs (except patella, carpals, tarsals) • Consists of shaft plus 2 expanded ends

23. The Skeleton

24. Skull Skull

27. Shoulder

28. Chest • Sternum • Ribs

29. Arm

30. Hand

31. Upper Extremity • Clavicle • Scapula • Sternum • Ribs • Humerus • Radius • Ulna • Carpals • Metacarpals • Phalanges

32. Spine/Pelvis • Pelvis • Sacrum • Pubic Bone/ • Pubis Sacrum Pubis

33. Os Coxa

35. Leg

36. Foot Tarsals

37. Lower Extremity

38. The Skeleton