1. Muscle Physiology Human Anatomy and Physiology II Oklahoma City Community College Dennis Anderson

2. Muscle Tissue Skeletal Muscle Cardiac Muscle Smooth Muscle

3. Skeletal Muscle Long cylindrical cells Many nuclei per cell Striated Voluntary Rapid contractions

4. Cardiac Muscle Branching cells One or two nuclei per cell Striated Involuntary Medium speed contractions

5. Smooth Muscle Fusiform cells One nucleus per cell Nonstriated Involuntary Slow, wave-like contractions

6. Microanatomy of Skeletal Muscle

8. Z line

12. H Band

13. Sarcomere Relaxed

14. Sarcomere Partially Contracted

15. Sarcomere Completely Contracted

18. Binding Site Tropomyosin Troponin

19. Myosin

21. Neuromuscular Junction

23. Acetylcholine Opens Na + Channel

25. Muscle Contraction Summary Nerve impulse reaches myoneural junction Acetylcholine is released from motor neuron Ach binds with receptors in the muscle membrane to allow sodium to enter Sodium influx will generate an action potential in the sarcolemma

26. Muscle Contraction Continued Action potential travels down T tubule Sarcoplamic reticulum releases calcium Calcium binds with troponin to move the troponin, tropomyosin complex Binding sites in the actin filament are exposed

27. Muscle Contraction Continued Myosin head attach to binding sites and create a power stroke ATP detaches myosin heads and energizes them for another contaction When action potentials cease the muscle stop contracting

28. Motor Unit All the muscle cells controlled by one nerve cell

29. Motor Unit Ratios Back muscles –1:100 Finger muscles –1:10 Eye muscles –1:1

30. ATP

31. Creatine Molecule capable of storing ATP energy Creatine + ATPCreatine phosphate + ADP

32. Creatine Phosphate Molecule with stored ATP energy Creatine + ATPCreatine phosphate + ADP

33. Muscle Fatique Lack of oxygen causes ATP deficit Lactic acid builds up from anaerobic respiration

34. Muscle Atrophy Weakening and shrinking of a muscle May be caused –Immobilization –Loss of neural stimulation

35. Muscle Hypertrophy Enlargement of a muscle More capillaries More mitochondria Caused by –Strenuous exercise –Steroid hormones

36. Steroid Hormones Stimulate muscle growth and hypertrophy

37. Muscle Tonus Tightness of a muscle Some fibers always contracted

38. Tetany Sustained contraction of a muscle Result of a rapid succession of nerve impulses

39. Tetanus

40. Refractory Period Brief period of time in which muscle cells will not respond to a stimulus

41. Refractory

42. Skeletal MuscleCardiac Muscle Refractory Periods

43. Isometric Contraction Produces no movement Used in –Standing –Sitting –Posture

44. Isotonic Contraction Produces movement Used in –Walking –Moving any part of the body

45. THE END