October 11, 2026

Glial cells greatly outnumber neurons—there are 2 to 10 times more glia than neurons in the vertebrate central nervous system.

Although the name for these cells derives from the Greek for glue, glia do not commonly hold nerve cells together. Rather they surround the cell bodies, axons, and dendrites of neurons. Glia differ from neurons morphologically; they do not form dendrites and axons. Glia also differ functionally. Although they arise from the same embryonic precursor cells, they do not have the same membrane properties as neurons and thus are not electrically excitable.

They are not directly involved in electrical signaling, which is the function of nerve cells. Yet they play a role in allowing electrical signals to move quickly along the axons of neurons, and they appear to play an important role in guiding connectivity during early development and stabilizing new or altered connections between neurons that occur through learning.