Gliové

Gliové, or glial cells, are the non-neuronal cells of the nervous system that provide support and protection for neurons. They are essential for the structure, maintenance, and function of neural networks and are more numerous than neurons in many brain regions.

In the central nervous system (CNS) the main glial cell types are astrocytes, oligodendrocytes, microglia, and ependymal cells. Astrocytes help regulate the extracellular ion balance, remove excess neurotransmitters, and contribute to the blood–brain barrier. Oligodendrocytes create myelin sheaths around CNS axons, increasing the speed of electrical signaling. Microglia act as resident immune cells, clearing debris and responding to injury. Ependymal cells line the brain’s ventricles and participate in the production and circulation of cerebrospinal fluid. In the peripheral nervous system (PNS), Schwann cells myelinate peripheral nerves, while satellite cells provide metabolic support to neuron cell bodies in ganglia.

Functions of gliové include structural support for neurons, maintenance of the extracellular environment, metabolic provision, synaptic modulation, and immune defense. They also participate in development and plasticity, guiding axon growth and synapse formation, and they contribute to repair processes after injury, particularly through remyelination in the PNS and CNS.

Clinical relevance centers on the role of glial cells in disease. Glial tumors, or gliomas, arise from glial cells and include astrocytomas and oligodendrogliomas. Glial dysfunction is implicated in multiple sclerosis, neuroinflammation, and various neurodegenerative conditions, highlighting the importance of gliové in nervous system health and disease.