Nerve cells, illustration. Nerve cells, also known as neurons or neurones, are excitable cells in the nervous system. They process and transmit information by electrochemical signalling. They are the core components of the brain, the spinal cord, and the peripheral nerves. Each nerve cell comprises a body surrounded by numerous extensions called dendrites. Dendrites collect information from other nerve cells or from sensory cells. Each neuron also has one process called an axon, which passes information to other nerve cells, or to effector cells such as muscle fibres.