glía

Glía, often referred to as glial cells or neuroglia, are a diverse group of cells in the nervous system that play a crucial role in supporting and protecting neurons. They are not neurons themselves, meaning they do not transmit nerve impulses, but their functions are essential for the overall health and operation of the nervous system. Glial cells are far more numerous than neurons in many parts of the brain, though their relative proportions can vary.

There are several major types of glial cells, each with specialized functions. In the central nervous system, astrocytes are the most abundant glial cells. They provide structural support, regulate the chemical environment around neurons by controlling ion concentrations and neurotransmitter levels, and contribute to the blood-brain barrier, which protects the brain from harmful substances in the bloodstream. Oligodendrocytes are responsible for forming the myelin sheath around axons in the central nervous system. This fatty insulating layer speeds up the transmission of electrical signals. Microglia are the immune cells of the central nervous system, acting as phagocytes to clear cellular debris and pathogens.

In the peripheral nervous system, Schwann cells perform a similar function to oligodendrocytes, producing the myelin sheath around peripheral nerve fibers. Satellite cells in the peripheral nervous system surround neuron cell bodies in ganglia, providing support and regulating the microenvironment. Glial cells are vital for neuronal survival, development, and function, and disruptions in their activity are implicated in various neurological disorders.