Glial cells

The brain is made up of two types of cells - neurons (or nerve cells) and Glial cells. Glial cells are non-neuron cells that provide supportive and nutritive functions. There are many more Glial cells in the nervous system then there are neurons. The myelin sheath that covers most axons is made up of glial cells.

When observed under a microscope they look like "glue between the nerve cells". There is still much that is unknown about Glial cells. What is known is that they do not have axons or dendrites (as neurons do) and they are not specialized to send or receive information.

One theory thus far is that they function as a physical support for neurons. This is based on observations in which the Glial cells seem to be regulating the internal environment of the brain especially the fluid surrounding neurons, and provide nutrition to the neurons.

Glial cells were discovered by a Spanish neuroanatomist named Santiago y Cajal.