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Neuroscience for Kids
Glia: The Forgotten Brain Cell
The brain is made up of more than just nerve cells (neurons). Although
there are about 100 billion neurons in the brain, there may be about 10 to
50 times that many glial cells in the brain. (New
research suggests the neuron-to-glia ratio may be smaller.) But do you
hear much about glia? NO! Because neurons get all the
attention, you don't hear too much about glia. Although glia cells DO NOT
carry nerve impulses (action potentials) they do have many important
functions. In fact, without glia, the neurons would not work properly!
Types and Functions of Glia
- Astrocyte (Astroglia): Star-shaped cells that provide
physical and nutritional support for neurons: 1) clean up brain "debris";
2) transport nutrients to neurons; 3) hold neurons in place; 4) digest
parts of dead neurons; 5) regulate content of extracellular space
- Microglia: Like astrocytes, microglia digest parts of
- Oligodendroglia: Provide the insulation (myelin) to
neurons in the central nervous system.
- Satellite Cells: Physical support to neurons in the
peripheral nervous system.
- Schwann Cells: Provide the insulation (myelin) to
neurons in the peripheral nervous system.
There are a few ways in which glia cells are different from
- Neurons have TWO "processes" called axons and dendrites....glial cells
have only ONE.
- Neurons CAN generate action potentials...glial cells CANNOT. However,
glial cells do have a resting potential.
- Neurons HAVE synapses that use neurotransmitters...glial cells do NOT
have chemical synapses.
- There are many MORE (10-50 times more) glial cells in the brain
compared to the number of neurons.
More information about glia:
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