Hi,

A nerve impulse starts when a stimulus makes sodium ions rush into the neuron, causing depolarisation. Then potassium ions move out, bringing the membrane back to its resting state. The impulse travels along the axon, moving faster in myelinated fibres because it jumps between nodes of Ranvier. At synapses, neurotransmitters like acetylcholine pass the signal to the next cell.

For more information, you can also check the resource:

https://www.careers360.com/biology/generation-conduction-transmission-of-nerve-impulse-topic-pge