1. Notes – Muscle Energy & Disorders

2. Review
Epimysium (outer covering of muscle)
Perimysium (covering fascicle)
Endomysium (covers each muscle fiber)
Fascicle (bundle of muscle fibers)

3. Myofibril (bundle in each muscle cell – made of actin & myosin)

4. Z - line
H - zone
A band
I band
sarcomere
Which band is the thin filament?
ACTIN
Which band is the thick filament?
MYOSIN

5. What are the 8 steps of muscle contraction?
Step 1: action potential to muscle
Step 2: ACETYLCHOLINE released from neuron
Step 3: acetylcholine binds to muscle cell membrane
Step 4: Na+ diffuse into muscle, action potential started
Step 5: Calcium ions bind to actin
Step 6: myosin attaches to actin, crossbridges formed
Step 7: myosin pulls on the actin causing it to slide over myosin
Step 8: ATP attaches to myosin to provide energy

6. Still More Interesting Muscle Facts
How many muscles does it take to produce human speech?
72 different muscles

7. 16 separate muscles – most people think its just 1
How many muscles make up the human tongue?
16 separate muscles – most people think its just 1

8. ENERGY REQUIREMENTS FOR MUSCLE CONTRACTION
ATP (adenosine triphosphate)
produced by aerobic respiration (with O2) or anaerobic respiration (without O2)
ATP used in long continuous exercise (EX: distance running)
Aerobic Respiration
fat is used for the fuel to make ATP with oxygen

9. Anaerobic Respiration
typically occurs during short periods of intense exercise
body uses CREATINE PHOSPHATE for energy (10-15 seconds)
body then switches to GLUCOSE for fuel
lactic acid is produced – fatigue & oxygen debt results

10. Disorder of Muscle Tissue
Cramps & Spasms
an “over contraction” – can be due to electrolyte imbalance, fatigue, overuse

11. Hernia
a tear in wall of muscle – can be congenital, or from severe strain

12. ABDOMINAL HERNIA

13. Muscle Tear
aka: “pulled” muscle or strained muscle – caused by overstretching of muscle during activity
Torn Pectoralis Major
muscle fibers actually tear apart

14. Hamstring Muscle Tear

15. Hypertrophy
increase in the size of muscle fibers
EX - Governor of California

16. Atrophy
decrease in size of muscle fiber

17. Types of Movements (terminology)
Origin
where a muscle begins
Insertion
where a muscle ends
Action
motion produced

18. Flexion
joint angle gets smaller

19. Extension
joint angle gets larger

20. hyperextension
movement beyond 180o of joint motion

21. abduction
movement away from midline of body

22. adduction
movement toward midline of body