The somatic nervous system also stimulates skeletal muscle contractions. Cells of the Nervous System Neurons are the cell type most thought of when one considers the nervous system. Axons, and dendrites to some degree, conduct electrical signals away from the soma. Axons terminate at some point where they release chemical neurotransmitters, thus altering an electrical method of communication to that of chemical communication. Pathways of the CNS also contain myelinated axons, and when a disease such as multiple sclerosis leads to demyelination, there are changes in affect, reasoning, and thought, as well as expected changes in skeletal muscle movement and strength.
Neuroglia are the supportive cells of nerve tissue.
These cell types do not normally conduct electrical signals, but rather perform other functions vital to the nervous system. Neuroglia includes astrocytes, ependymal cells, microglia, oligodendrogliocytes, Schwann cells, and Satellite cells. Astrocytes surround blood vessels that course througha the brain, controlling what may cross the blood vessels to enter brain. Microglia have phagocytic functions, scouring up dead cells and cleaning up debris. Schwann cells and oligodenroglia create myelin sheaths as already described.