By Kathy Kukula


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