How do brain cells get their messages across? Messages travel
through brain cells, also called nerve cells or neurons, as electricity.
Neurons have threadlike fibers called axons that send messages and
branches called dendrites that receive them. To make messages jump
from cell to cell—when your brain signals your hand to scratch
your head, for example—your brain creates chemicals called neurotransmitters.
Whenever you think or act, axons release these chemicals. Dendrites
have receptors, like custom-made garages, into which each chemical
fits. A fatty, white coating called myelin covers many axons; it helps
messages move quickly, especially along the long axons that connect
to muscles.
From Scholastic and the Scientists of the National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services
