2. Muscle Physiology: The Actions of the Sarcomere.

3. Cardiac Muscle Characteristics Intercalated disks Striated Involuntary Located in heart

4. Skeletal Muscle Characteristics Many nuclei per cell Striated Voluntary Located along bones

5. Nonstriated Involuntary Located in digestive tract Smooth Muscle

6. Functions of Muscles Movement : results from muscle contraction, enables you to respond quickly Maintains Posture and Joint Stability : allows you to sit upright; stabilize joints of the body Support Soft Tissue: abdominal muscles protect underlying digestive organs. Guard Entrances and Exits Generate Heat : heat is generated as they work…FRICTION Maintains body temperature Skeletal muscles create the most heat

7. Characteristics of Muscle Tissue Excitability: ability to receive and respond to stimuli… Contractibility: ability to shorten quickly and with force… Extensibility: ability to be stretched or extended beyond their resting state… Elasticity: ability of a muscle fiber to recoil and resume its resting length

8. Organization of Muscle Muscles are composed of groups of fibers called fasicles. Fibers are the muscle cells inside all muscle. Tendons are bands of collagen fiber that attach muscle to bone.

11. Sarcomere: the contracting unit

12. Skeletal Muscle Striations

13. Z line I band H band A band

15. Organization from the muscle fiber to the sarcomere.

16. Cross sectional view of Sarcomere. Differences are detected in the sizes of the myofilaments Myosin is the thicker fiber. Actin is the thinner fiber.

17. Striations are seen because of sarcomere bands..

18. Muscle fiber structure Muscle cell Sarcolemma Sarcoplasm Sarcoplasmic reticulum T tubule mitochondria

19. Structure of Muscle Tissue

20. Sliding Filament Theory

21. Sliding Filament Theory Actin slides over myosin shortening the sacromere between the Z lines

27. Chain of Events during Muscle Contraction! 1. Cross Bridge Attachment 2. Power Stroke 3. Cross Bridge Detachment 4. Cocking (Recoil) of Myosin Head

28. What happens at the sarcomere?

29. Players for the power stroke Cross bridge attachment Power strokes Cross bridge detachment “Cocking” of the myosin head

30. Power stroke

31. Motor Unit: A motor neuron and all the muscle fibers it stimulates.

32. Diagram of a Muscle Twitch

33. Increase in muscle tension due to continued stimulation.

34. Muscle that reaches peak tension during rapid cycles of contraction and relaxation.

35. Complete tetanus = relaxation state is eliminated.

36. Label the following!

38. Aerobic Muscle Metabolism Glycolysis Aerobic Respiration Krebs Cycle ETC

39. Anaerobic Muscle Metabolism Oxygen Debt Lactic Acid Fermentation Muscle Fatigue

40. Creatine Phosphate

41. Red (slow) twitch fibers Aerobic Slow-acting ATPases (enzymes that break down ATP) Large amounts of myoglobin Red color to cell Abundant supply of mitochondria Fatigue resistant-as long as O2 is available High endurance (jogging, swimming, soccer)

42. White (fast) twitch fibers Large pale cells with twice the diameter of red fibers Very little myoglobin Contain fast-acting ATPases and contract rapidly Contain few mitochondria, but large glycogen stores Depend on anaerobic resp. to make ATP, therefore fatigues easily Low endurance, much power….sprints

43. Pink (intermediate) twitch fibers Mixture of red and white fibers Aerobic mechanisms and fatigue resistant Contain fast-acting ATPases High myoglobin content