Glial cells

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The nervous system is a sophisticated network consisting of nerve cells (neurons) and glial cells. Glia, unlike neurons, are not directly involved in the conduction of electrical signals, but are crucial to the normal functioning of the nervous system. They are nonneuronal cells and comprise the majority of cells found in the nervous system. They create and maintain an optimal environment for neurons to function properly, ensuring the health and stability of neural activity.

In the central nervous system (CNS), there are four major types of glial cells, each with specific functions. Astrocytes maintain the blood-brain barrier, provide structural support and regulate ion balance and nutrient supply to neurons. Oligodendrocytes form the myelin sheath around axons, enabling rapid conduction of electrical impulses. Microglia act as the immune cells of the CNS, removing debris and protecting against pathogens. Ependymal cells line the ventricles of the brain and the central canal of the spinal cord, contributing to the production and circulation of cerebrospinal fluid.

In the peripheral nervous system (PNS), the two main types of glial cells are Schwann cells (neurolemmocytes) and satellite cells. Schwann cells are analogous to the oligodendrocytes in the CNS, forming the myelin sheath around axons in the PNS to enhance signal transmission. Satellite cells provide support to neurons in peripheral ganglia, regulating the environment around the neuronal cell bodies.

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Types of central glial cells

There are four types of glial cells found within the central nervous system: oligodendrocytes, astrocytes, ependymal cells and microglia. Learn more about each type below.

Types of peripheral glial cells

There are two types of glial cells found within the peripheral nervous system: Schwann cells and satellite cells. Learn more about these cells below.

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