Glial cells

Supporting cells on a myelinated axon.

Glial cells support the function of neurons in the nervous system.

They provide structural support and insulation for neurons, help maintain a healthy blood supply within the brain, and function as immunological sentinels.

There are many different types of glial cells, each with its own definition and function.

  • Astrocytes, for example, are star-shaped cells that maintain the blood-brain-barrier and support neurons by supplying the building blocks of neurotransmitters and transferring mitochondria to neurons.
  • Oligodendrocytes produce myelin (a fatty sheath that wraps around some nerve axons) to provide electric insulation and accelerate neuronal signal transmission. Their equivalents in the peripheral nervous system are called Schwann-cells.
  • Microglia are the primary immune cells of the central nervous system (CNS). They remove debris via phagocytosis and constantly survey their environment to identify damaged cells and infectious agents. When they find these, they engulf them and then present fragments of them to other immune cells.

Use our interactive animations and diagrams below to study the anatomy and function of glial cells in the nervous system.