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Regulation of contraction

Regulation of contraction - Regulation of contraction the...

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Regulation of contraction: - the axon of a motor neuron forms a neuromuscular junction with a muscle fiber - the neurotransmitter acetylcholine (ACh) is released in synaptic vesicles from the axon terminal of the nerve cell into the synaptic cleft between the nerve cell & muscle cell - the motor end plate of the muscle cell has ACh receptors that bind ACh; this binding opens sodium channels in the sarcolemma... sodium rushes in & triggers an action potential in the muscle cell: o muscle cells are polarized with slight negative charge in resting state o depolarization of the muscle cell results from the excess positive charge caused by the influx of sodium ions o the local depolarization spreads to the rest of the muscle cell o repolarization occurs as potassium ions flow out of the muscle cell to restore the resting potential - ACh is degraded by ACh esterase in synaptic cleft - Excitation-contraction coupling: transmission of action potential past triads causes
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