Neuroanatomy and glial cells come in many types (see, for example, the nervous system section of the list of distinct cell types in the adult human body). Neurons are the information-processing cells of the nervous system: they sense our environment, communicate with each other via electrical signals and chemicals called neurotransmitters across synapses, and produce our memories, thoughts and movements. Glial cells maintain homeostasis, produce myelin, and provide support and protection for the brain's neurons. Some glial cells (astrocytes) can even propagate intercellular calcium waves over long distances in response to stimulation, and release gliotransmitters in response to changes in calcium
Satellite glial cell found in different cells. Although SGCs express glial fibrillary acidic protein (GFAP) and different S-100 proteins, the most useful marker available today for SGC identification is glutamine synthetase (GS). The levels of GS are relatively low at rest, but they greatly increase if the neuron undergoes axonal damage. Furthermore, SGCs also possess mechanisms to release cytokines, adenosine triphosphate (ATP), and other chemical messengers. Research is currently ongoing in determining the physiological role of satellite glial cells. Current theories suggest that SGCs have a significant role in controlling the microenvironment of the sympathetic ganglia. This is based on the observation that