Neuroglia responsible the manufacture the myelin sheath that insulates and supports axons in most vertebrates (only jawless fish such as hagfish and lampreys do not have oligodendrocytes, but they are absent in the retina of humans, mice and rats). In the peripheral nervous system, this function resides with Schwann cells. Oligodendrocytes are not only found in white matter, but also in gray matter. Referred to satellite oligodendrocytes, their functions are not properly understood but are thought to regulate the extracellular fluid in some way. Oligodendrocytes arise from precursors found in the sub-ventricular zone of the cerebral lateral ventricles and the fourth ventricle of the cerebellum. In the spinal cord, they originate from the ventral regions of the neural tube; in the optic nerve, they migrate to it from the third ventricle. Excess oligodendrocytes are pruned back by apoptosis. Damage to oligodendrocytes (e.g., through excessive release of the neurotransmitter glutumate) can give rise to cerebral palsy, multiple sclerosis and strokes.
See Apoptosis (or cell death), Axon, Cerebral palsy, Extracellular matrix, Glutumate (or glutamate), Gray matter, Myelin, Myelination, Neural tube, Optic nerve, Peripheral nervous system, Purines, Retina, Schwann cells, Ventricle, White matter