Scientists Say: Glia | Science News for Students

Scientists Say: Glia

These brain cells glue the brain together — and do a lot more
Oct 16, 2017 — 6:50 am EST
glial cells

This image has drawings of three different types of glial cell — astrocytes, microglia and oligodendrocytes. Each has its own important function. (Other labels mark neurons and parts of neurons.)


Glia (noun, “GLEE-uh”)

This word is short for “neuroglia,” but they’re just “glia” to their friends. Glia are a type of cell in the nervous system. An adult man has about 85 billion glia and about 86 billion neurons — cells in the brain that conduct electrical signals.

The term glia comes from the Greek word for “glue.” Scientists used to think that glial cells were simply the glue of the nervous system, helping to hold brain and nerves together. But now we know that there are many types of glia, and they perform many important functions in the brain. Glia do help hold the nervous system together. But glial cells also provide other brain cells with food and oxygen. These are astrocytes. Glia called oligodendrocytes wrap around long parts of neurons to help their electrical signals move faster. And microglia help protect the brain from dangerous infections or damage.

In a sentence

The glia that act as the brain’s immune system can also control how much weight a mouse gains or loses when it eats a fatty diet.

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Power Words

(more about Power Words)

astrocyte     A type of non-nerve cell found in the brain.

cell     The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.

diet     The foods and liquids ingested by an animal to provide the nutrition it needs to grow and maintain health. (verb) To adopt a specific food-intake plan for the purpose of controlling body weight.

glia     Non-nerve cells, these make up about half of the cells in the brain. Some glial cells wrap around axons. This speeds the rate of neural signaling and helps prevent confusing “cross-talk” between neighboring nerve cells. Other glial cells provide nutrients and oxygen to neurons, or defend the nervous system from injury.

glue     A sticky substance that attaches one material to another.

immune     (adj.) Having to do with the immunity. (v.) Able to ward off a particular infection. Alternatively, this term can be used to mean an organism shows no impacts from exposure to a particular poison or process. More generally, the term may signal that something cannot be hurt by a particular drug, disease or chemical.

immune system     The collection of cells and their responses that help the body fight off infections and deal with foreign substances that may provoke allergies.

infection     A disease that can spread from one organism to another. It’s usually caused by some type of germ.

microglia     A type of cell found in the brain and spinal cord. It can move from place to place, and serve as part of the immune system, protecting the brain from infection.

nerve     A long, delicate fiber that transmits signals across the body of an animal. An animal’s backbone contains many nerves, some of which control the movement of its legs or fins, and some of which convey sensations such as hot, cold or pain.

nervous system     The network of nerve cells and fibers that transmits signals between parts of the body.

neuron     An impulse-conducting cell. Such cells are found in the brain, spinal column and nervous system.

oxygen     A gas that makes up about 21 percent of Earth's atmosphere. All animals and many microorganisms need oxygen to fuel their growth (and metabolism).