The neuron.

A neuron is a very specialized cell that forms the basis of the nervous system. It is also referred to as anerve cells. Neurons are unique in that they transmit signals throughout the body. These signals are referred to as action potentials, nerve impulses or spikes. Lets make this very practical. If you need to send a signal very quickly to a part of the body, the neuron is the cell for the job. Your brain needs to tell your hand to move? It sends that signal via neurons. You touch a hot stove, the signal needs to go to your brain quickly, so that you can realize that it hurts and pull your hand away before you do some serious damage, neurons send that signal faster than you can say OUCH!