Oligodendroytien

Oligodendroytien, commonly spelled oligodendrocyten, are glial cells of the central nervous system responsible for forming and maintaining the myelin sheath around axons. They reside primarily in the white matter, but their processes also extend into gray matter. A single oligodendrocyte can extend multiple processes to myelinate segments of several different axons.

Structure and development: Oligodendrocytes differentiate from oligodendrocyte precursor cells (OPCs) that originate during development and migrate into the CNS. Mature cells express specific transcription factors such as Olig2 and Sox10, and surface markers including NG2 and PDGFR-alpha. Each oligodendrocyte wraps its processes around axons to form the myelin sheath, creating internodes separated by nodes of Ranvier.

Function: The primary role of oligodendrocytes is to insulate axons with a myelin sheath, which increases the speed of electrical impulse conduction via saltatory conduction. Myelin reduces membrane capacitance and increases electrical resistance, enabling rapid communication along neural circuits. In addition to insulation, oligodendrocytes contribute metabolic support to axons through transporters like MCT1.

Remyelination and disease: Following injury or demyelinating disease, oligodendrocyte precursor cells can differentiate into mature oligodendrocytes to replace lost myelin, though this remyelination often declines with age. Oligodendrocyte dysfunction or loss of myelin is a central feature of several disorders, most notably multiple sclerosis, where immune-mediated damage disrupts CNS myelin.

Comparison: In the central nervous system, one oligodendrocyte can myelinate multiple axons, whereas peripheral nervous system Schwann cells typically myelinate individual axons.