Illustration of a neuron or nerve cell which forms part of the nervous system which processes and transmits information by electrical and chemical signalling. The following anatomies in the neuron are labelled: (from top right going clockwise): dendrodendritic synapse, presynaptic neuron, synaptic end bulb, synaptic cleft, ligand-gated channel, postsynaptic neuron, Na, neurotransmitter, cytoplasm, Ca2, and Nerve impulse.