How does an electrical impulse travel the gap between two nerves?

The electrical impulse that travels along a nerve, known in biology as an action potential, gets passed along to an adjacent nerve as a chemical signal. When an action potential reaches the end of a nerve, it triggers the opening of calcium ion channels and calcium enters the neurone. The increased concentration of calcium stimulates vesicles containing a chemical neurotransmitter to move towards the membrane. When the vesicles fuse with the membrane, the neurotransmitter is released into the gap between the nerves, known as the synapse. The nerve receiving the signal has receptors in its surface, which detect the presence of this neurotransmitter in the synapse. When the receptor binds the neurotransmitter, it stimulates the neurone to produce an action potential that continues to propagate.