1. Skeletal and Muscular Systems

2. Skeletal System The framework for your body 206 bones “Os-” bone; “Osteo-” bone

4. Osteocytes are bone cells

5. Bone contains: Minerals – especially calcium which provides for the hardness of bone Collagen fibers which provides strength of bone

6. Bone has an excellent blood supply

7. Joint “art-” and “arthr-” mean joint Ligaments stabilize joints Cartilage caps the bones at the joint for a smooth surface

9. Cartilage “chondr-” means cartilage Healing capability is poorer than bone

11. Skeleton Function Framework Support Movement Protection Blood cell production from bone marrow Storage of minerals & fat

12. Disorders of Skeleton-Osteoporosis

13. Incidence Common in the U.S. Responsible for many fractures each year

14. Cause Inadequate calcium Females, older more commonly Sedentary lifestyle Poor diet Pregnancy giving calcium to fetus Menopause lead to calcium withdrawal from bone

15. Prevention/Treatment Weight-bearing exercise Calcium in diet Estrogen replacement therapy after menopause Drugs, such as Fosamax

16. Arthritis Rheumatoid arthritis is an autoimmune disease in which the immune system attacks the joints in the body leading to their gradual destruction

17. Arthritis Osteoarthritis is the wear and tear arthritis due to joint damage and injuries

18. Sprain Joint injury that stretches or tears supportive ligaments A severe sprain can result in a dislocation

19. Fracture Generally bones heal well with proper alignment, stabilization, and without infection

21. Fractures Hairline or greenstick Simple Compound = Open Comminuted

22. Muscular System “Myo-” means muscle Muscle tissue is capable of contraction

23. Smooth muscle Found in the wall of tubular structures such as intestine Involuntary Smooth appearance microscopically Peristalsis is a wave like contraction of smooth muscle

26. Cardiac Muscle Heart muscle Involuntary Striated, or striped when observed microscopically

28. Skeletal Muscle Muscle attached to the skeleton Voluntary Striated microscopically

31. Skeletal Muscle Tendons attach muscle to bone

33. Microscopic Muscle Myofiber = muscle cell Myofibril = the striated parts of the muscle cell Myofilaments = the proteins that make up the myofibrils

35. Myofilaments The two main proteins that comprise the myofilaments are: –Myosin – very thick protein –Actin – very thin protein

37. Sarcomere The actin and myosin in the muscle cells are arranged in small groups called SARCOMERES Since contraction occurs at the microscopic level of the sarcomere, the sarcomere is the functional unit of contraction

39. Sliding Filament Theory This describes the mechanics of muscle contraction The myosin “heads” grab on to the actin protein and pull the actin towards the center of the sarcomere, making the sarcomere shorter.

44. ATP ATP is necessary for muscle contraction Running out of ATP leads to muscle fatigue

45. Motor Neuron Skeletal muscle will not contract unless a motor neuron (movement nerve cell) stimulates it to contract

47. Motor Unit A motor neuron plus how every many skeletal muscle cells it serves is a motor unit A motor unit that has one neuron to one muscle cell allows for very precise movements A motor unit that has one neuron to 400 muscle cells does not provide precise control