What is the nervous system made of?

The basic building blocks of the brain and nervous system are neurons (also known as neurones or nerve cells). Neurons are the cells that receive sensory information from the outside world, give motor commands to our muscles, and transform and relay electrical signals at each stage along the way. Beyond that, our interactions with them shape who we are as people. Despite this, our approximately 100 billion neurons do interact intimately with other cell types that are often referred to as glia (although it is unknown if glia actually outnumber neurons).