There are two types of ion channels involved in the neuromuscular junction and end plate potentials: voltage-gated ion channel (responsive to changes in membrane voltage which cause the voltage gated ion channel to open) and ligand-gated ion channel (responsive to certain molecules such as neurotransmitters).
The resting membrane potential of a motor neuron goes from -70mV to -50 with a higher concentration of sodium outside and a higher concentration of potassium inside. <em>When an action potential propagates down a nerve and reaches the axon terminal of the motor neuron, the change in membrane voltage causes the calcium voltage gated ion channels to open allowing for an influx of calcium ions. </em>These calcium ions cause the acetylcholine vesicles to release acetylcholine via exocytosis into the synaptic cleft.
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