2. Functions of Muscle 1.Producing Movement Locomotion Manipulation
Respond quickly

3. Functions of Muscle
2. Maintaining Posture
Defy gravity

4. Functions of Muscle
3. Stabilizing Joints

5. Functions of Muscle 4. Generate Heat
Important in maintaining body temperature

6. Naming Muscles 1. Location 2. Shape 3. Size 4. Direction of fibers
5. Number of origins
6. Location of attachements
7. Action

7. Muscle Tissue Skeletal (striations, voluntary, tires easily, strong)
Smooth (found in hollow organs, force things through passage, involuntary, slow)
Cardiac (heart, involuntary)

8. Gross Anatomy of Muscle
Each skeletal muscle fiber is supplied with a nerve ending that controls activities

9. Microscopic Anatomy Muscle
Muscle fibers
Long, cylindrical, oval nuclei, multiple nuclei, HUGE

10. Microscopic Anatomy Muscle
Sarcoplasm- cytoplasm of muscle cells
Myoglobin- red pigment, stores oxygen

12. Microscopic Anatomy Muscle
Myofibrils
Muscle fibers have many of these
Contain contractile elements of skeletal muscle cells

13. Microscopic Anatomy Muscle
Striations
A Band
I Bands
H Zone
M Line
Z Disc

14. Microscopic Anatomy Muscle
A and I Bands
Aligned with one another
Gives the stripped appearance

15. Microscopic Anatomy Muscle
H Zone
Visible only in relaxed muscle
In the A Band

16. Microscopic Anatomy Muscle
M Line
In H Zone

17. Microscopic Anatomy Muscle
Z Disc
In the I Band
Midline line

19. Microscopic Anatomy Muscle
Sarcomere
Muscle segment
Region between 2 Z Discs
Smallest contractile unit of muscle

21. Microscopic Anatomy Muscle
Myofilaments
Within sarcomeres
Thick and thin filaments
Thick- actin
Thin- myosin

22. Microscopic Anatomy Muscle
Myosin
Rod-like tail with 2 “heads”
Heads link the actin with myosin (form cross bridges)
Actin binding sites
ATP binding sites
Enzymes-Split ATP to generate energy for contraction

23. Microscopic Anatomy Muscle
Actin
Contains tryptomyosin- block active sites in relaxed muscle
Troponin- binds to actin, contains Calcium releasing sites for muscle contraction

24. Microscopic Anatomy Muscle
Sarcoplasmic Reticulum
Surround each myofibril
Regulate intracellular levels of Calcium
Contract- release calcium
GO signal for contraction

25. Sliding Filament Model of Contraction
Contraction- myosin heads attach to actin forming cross bridges
Relaxation- cross bridges inactive

26. Sequence of Events in Muscle Contraction
1. Action potential stimulates sarcolemma
2. Sarcolemma releases Calcium
3. Myosin binding sites on actin are exposed

27. Sequence of Events in Muscle Contraction
4. Cross bridge formation (myosin hooks onto actin)
5. Power Stroke- myosin pulls on actin sliding it towards sarcomere, ATP  ADP + P (MOVEMENT)

28. Sequence of Events in Muscle Contraction
6. Cross bridge detachment- ATP is replaced which causes myosin to detach from actin
7. Myosin head returns to normal position (ready for next stimuli)

30. Motor Unit

31. Muscle Fatigue
Oxygen is limited and ATP production fails to meet ATP needs
Physiological inability to contract even though muscle still receives stimuli
Lactic acid buildup

32. Oxygen Debt
Extra amount of oxygen body must take in to restore muscles & rid the body of lactic acid (liver)

33. Exercise and Muscles Aerobic exercise Increase in capillaries
Increased number of mitochondria

34. Smooth Muscle Contractions like skeletal muscle
Calmodulin helps with contraction since smooth muscle does not have troponin

35. Muscular Dystrophy Inherited muscle destroying diseases
Duchenne Muscular Dystrophy
Sex linked recessive (boys)
No cure but medication has developed

36. Disuse Atrophy Don’t work out, bed rest, immobility
Degeneration and loss of muscle mass
Decrease at 5% each day
Replaced by cartilage (rehabilitation impossible)