In addition to neurons, the nervous system is populated with another category of cells, glial cells. Glial cells are approximately 10 times more plentiful than neurons, but since they are approximately one-tenth the size, they take up equal size, glia is a Greek term meaning glue, researches originally believed that glial cells served as the putty that held the neurons together, recent research indicates that these cells provide very important contributions.

　　a neuron is the functioning unit of the nervous system, specialized to receive, integrate, and transmit information, the flow of information moves in the following direction.