Neurotransmitters play a critical role in addition. The basic unit of communication in the nervous system is the nerve cell (neuron). Each nerve cell consists of the cell body, a major branching fiber (axon) and numerous smaller branching fibers (dendrites). Nerve cells use chemicals called neurotransmitters to communicate with adjacent nerve cells across gaps at contact points called synapses. Neurotransmitters are received by receptors on other nerve cells.