Science with Mandy

What are glia, you might ask? Well, I will tell you! They are my personal favorite type of cell in the world (yes, I love them even more than neurons). In the central nervous system (CNS), there are three main types of glial cells (sometimes referred to as neuroglia): microglia, astrocytes, and oligodendrocytes. Each type plays its own key role in maintaining the proper function and health of the body.

Microglia act as the “scavengers” of the brain, where they work hard to engulf, or phagocytose, various cellular debris, helping maintain a clean and healthy environment for neurons to flourish (1). Microglia are also involved in mediating inflammation and can promote the release of proinflammatory and antiinflammatory molecules, like cytokines (molecules released from one cell to induce a reaction in another). After a CNS injury, like a traumatic brain injury, you will likely see an increase in microglial presence around the site of injury, where the cells are flocking to do their jobs in helping promote neuronal health (2).

Astrocytes, named for their star-like shape, are the most abundant cell type in the CNS. Astrocytes have many, many important roles in the CNS, ranging from neuronal metabolic support to assistance in action potential propagation to neurotransmitter turnover from the synaptic cleft. Additionally, astrocytes help form the blood brain barrier, which prevents many harmful things, like bacteria, from entering the brain through the bloodstream (3).

Oligodendrocytes, also known as oligodendroglia, generate myelin, a layer of lipid-rich material that surrounds the axons of some neurons (outside the CNS, Schwann cells are the myelinators). Myelination helps neurons to send action potentials down their axons faster and is associated with neuroplasticity (1).

Overall, these three types of cells that make up the glia family are important in maintaining the health and homeostasis of the CNS. Other cell types are important, as well, but these are three key ones!

Works Cited

1. Purves, D., Augustine, G. J., Fitzpatrick, D., Katz, L. C., LaMantia, A.-S., McNamara, J. O., & Williams, S. M. (2001). Neuroglial cells. Neuroscience. 2nd Edition. https://www.ncbi.nlm.nih.gov/books/NBK10869/
2. Shao, F., Wang, X., Wu, H., Wu, Q., & Zhang, J. (2022). Microglia and neuroinflammation: Crucial pathological mechanisms in traumatic brain injury-induced neurodegeneration. Frontiers in Aging Neuroscience, 14, 825086. https://doi.org/10.3389/fnagi.2022.825086
3. Wei, D. C., & Morrison, E. H. (2023). Histology, astrocytes. In StatPearls. StatPearls Publishing. http://www.ncbi.nlm.nih.gov/books/NBK545142/