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Section 9.3 Muscle Contraction. Neuromuscular Junction.

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Presentation on theme: "Section 9.3 Muscle Contraction. Neuromuscular Junction."— Presentation transcript:

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?

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