Slide 1

Section 9.3 Muscle Contraction

Slide 2

Neuromuscular Junction

Slide 3

Polio Damages motor neurons

Slide 4

The Synapse

Slide 5

Myasthenia Gravis Autoimmune disease Destroys Ach receptors

Slide 6

Botulism Bacterial toxin Prevents release of ACh

Slide 7

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

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Slide 9

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

Slide 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

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Slide 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

Slide 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?