Nerve impulse transmission is the process by which signals are sent along neurons, the specialized cells of the nervous system. When a neuron is stimulated, it generates an electrical signal called an action potential. This signal travels down the neuron's axon, a long, thin extension, by causing a series of rapid changes in the electrical charge across the cell membrane. As the action potential reaches the end of the axon, it triggers the release of neurotransmitters, chemical messengers that cross the synapse, the gap between neurons. These neurotransmitters bind to receptors on the next neuron, continuing the transmission of the nerve impulse and allowing communication throughout the nervous system.