1. Section 9.3 Muscle Contraction

2. Neuromuscular Junction

3. Polio Damages motor neurons

4. The Synapse

5. Myasthenia Gravis Autoimmune disease Destroys Ach receptors

6. Botulism Bacterial toxin Prevents release of ACh

7. Impulse causes SR to release Ca 2+ Ca 2+ binds to troponin and changes its shape

9. P i (inorganic phosphate) and ADP released during the power stroke Actin is pulled to middle of sarcomere

10. New ATP binds to myosin which releases the cross-bridge = relaxation ATPase breaks down ATP into ADP and P i and cycle starts again

14. Rigor Mortis Without ATP, the sarcomere cannot relax Lasts 72+ hours until muscle fibers decompose (AChE) Acetylcholinesterase – breaks down Ach in synapse Stops impulse to sarcolemma Ca2+ pump 9which needs ATP) moves back to equilibrium Cross-bridges are broken

15. The next Powerpoint will explain: Where does the ATP come from? What happens when we run out of ATP? Why do I get a cramp in my side when I work out? How are trained athletes’ muscles more efficient?