The cells of the Central (CNS) and Peripheral (PNS) nervous systems can be broadly grouped into two categories, neuron and glia cells. While neurons are the primary signaling cells of the nervous system, glia provide support functions to the neurons in a variety of different ways.
A typical neuron is composed of a cell body (Soma), an axon and dendrites. The axon carries electrical nerve impulses away from the Soma, while the dendrites receive signals from neighboring neurons. Each neuron is able to form connections with hundreds of other neural cells via intercellular communication occurring in specialized gaps known as synapses.
Glial cells, in contrast, support neurons by providing protection and maintaining homeostasis. Essential to healthy functioning neurons, glia perform a diverse range of functions, such as nutrient provision, regulation of ion concentration, mediating immune response, and the removal of cellular waste. Glial cell types include astrocytes, ependymal cells, microglia, oligodendrocytes, satellite cells (PNS) and schwann cells (PNS).