Explain how an AP from the motor neuron results in muscle contraction. Include d
ID: 3515907 • Letter: E
Question
Explain how an AP from the motor neuron results in muscle contraction. Include details about excitation, excitation-contraction coupling, prep for contraction, and contraction. Explain how an AP from the motor neuron results in muscle contraction. Include details about excitation, excitation-contraction coupling, prep for contraction, and contraction. Explain how an AP from the motor neuron results in muscle contraction. Include details about excitation, excitation-contraction coupling, prep for contraction, and contraction.Explanation / Answer
Neuron action potential arrives at end of motor neuron and synaptic vesicles release acetylcholine.Acetylcholine binds to receptors on motor end platesSodium ions rushes in to the muscle fibre,the outside of the fibre briefly becomes negatively charged at that point.Adjacent to this point,a part of the fibre remains positively charged.This difference in potential between the two areas is called the action potential.Muscle action potential sweeps into T tubules.When a nerve impulse arrives at the junction between nerve ending and the muscle the sarcolemma of a muscle fibre is deploarized.Subsequently,the depolarization of sarcolemma is transmmited to the interior of the muscle fibre by a plexus of channels the sacroplasmic reticulum.Calcium ions are maintained in this sarcoplasmic reticulum when a muscle is in the resting state.This is accomplished by an energy -requring active transport system for calcium ions.
Excitation of a motor nerve to the muscle brings about release of calcium ions from sacrolemma.The released calcium binds to the TpC subunit of the troponin complex,producing conformational changes which are transmitted to tropomyosin and then actin proteins of the thin filament.This permits actin to interact with myosin with resultant muscular contraction.
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