Neurons Stock Image

The human body is made up of trillions of cells. Cells of the nervous system, called nerve cells or neurons, are specialized to carry messages through an electrochemical process. The human brain has approximately 100 billion neurons. Neurons come in many different shapes and sizes. Some of the smallest neurons have cell bodies that are only 4 microns wide. Some of the biggest neurons have cell bodies that are 100 microns wide.