The neurons lie end-to-end in a chain to transmit the impulses in an animal body. There occurs a very minute gap between the terminal portion of axon of one neuron and dendron of the other neuron. This gap is called synapse. At the end of the axon, the electrical impulse sets off the release of some chemicals. These chemicals cross the gap (synapse) and start a similar electrical impulse in the dendrite of the next neuron.