Describe the events that occur from the time that a motor neuron releases acetylcholine at the neuromuscular junction until muscle cell contraction occurs
What will be an ideal response?
Acetylcholine (ACh) is released from the axon terminals of a motor neuron, which diffuses across the synaptic cleft and attaches to receptors in the sarcolemma. ACh binds and opens channels that allow the simultaneous passage of sodium ions into the muscle fiber and potassium ions out of the muscle fiber. Since more sodium ions enter the muscle fiber than potassium ions leave, a local area of depolarization develops. As more channels that only allow sodium entry open, an action potential is initiated and sweeps over the entire sarcolemma. Calcium ions are released from storage areas inside the sarcoplasmic reticulum of the muscle cell. They attach to the myofilaments, which triggers the sliding of the myofilaments and causes a muscle cell contraction.
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Fill in the blank(s) with correct word
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