Oligodendrocyte

Oligodendrocyte

Neuron with oligodendrocyte and myelin sheath

An oligodendrocyte is a type of glial cell in the central nervous system (CNS) of vertebrates. Their main function is to provide support and insulation to axons in the form of a myelin sheath, which is essential for the proper functioning of the nervous system.

Structure

Oligodendrocytes are characterized by their small cell bodies and the presence of multiple processes that extend from the cell body. These processes wrap around the axons of neurons to form the myelin sheath. Each oligodendrocyte can myelinate multiple axons, unlike Schwann cells in the peripheral nervous system, which myelinate only one axon.

Illustration of an oligodendrocyte

The myelin sheath is composed of multiple layers of the oligodendrocyte's plasma membrane, which is rich in lipids and proteins. This composition is crucial for the insulating properties of the myelin sheath, which facilitates the rapid transmission of electrical signals along the axon.

Function

The primary function of oligodendrocytes is to myelinate axons in the CNS. Myelination increases the speed of action potential propagation along the axon through a process known as saltatory conduction. This is achieved by the myelin sheath insulating the axon and allowing the action potential to "jump" between the nodes of Ranvier, which are gaps in the myelin sheath.

Oligodendrocytes also play a role in maintaining the health and stability of axons. They provide metabolic support to neurons and are involved in the regulation of ion concentrations around the axon.

Development

Oligodendrocytes originate from oligodendrocyte precursor cells (OPCs), which are derived from neural stem cells in the ventricular zone of the developing brain. OPCs migrate to their target locations in the CNS, where they differentiate into mature oligodendrocytes and begin the process of myelination.

The development and differentiation of oligodendrocytes are regulated by a variety of growth factors and signaling pathways, including platelet-derived growth factor (PDGF) and neuregulin.

Clinical Significance

Oligodendrocytes in rat brain

Dysfunction or damage to oligodendrocytes can lead to a variety of neurological disorders. One of the most well-known conditions associated with oligodendrocyte damage is multiple sclerosis (MS), an autoimmune disease in which the body's immune system attacks the myelin sheath, leading to demyelination and impaired nerve function.

Oligodendrocyte dysfunction is also implicated in other diseases such as leukodystrophies, which are genetic disorders affecting the growth or maintenance of the myelin sheath, and certain types of brain tumors, such as oligodendrogliomas.

Related Pages

• Myelin
• Glial cell
• Central nervous system
• Multiple sclerosis
• Schwann cell