What is a neuron?

The neuron is a nerve cell. The brain is made up of approximately 100 billion neurons.

Neurons are similar to other cells in the body in the following ways:

Neurons are surrounded by a membrane.
Neurons have a nucleus that contains genes.
Neurons contain cytoplasm, mitochondria and other "organelles".
However, neurons differ from other cells in the body in the following ways:

Neurons have specialized projections called dendrites and axons. Dendrites bring information to the cell body and axons take information away from the cell body.
Neurons communicate by means of electrochemical processes.
Neurons form specialized connections called "synapses" and produce special chemicals called "neurotransmitters" that are released at synapses.