Neurons (or nerve cells) are specialized cells that transmit and receive electrical signals in the body. Neurons are composed of three main parts: dendrites, a cell body, and an axon. Signals are received through the dendrites, travel to the cell body, and continue down the axon until they reach the synapse. Your ability to perceive your surroundings – to see, hear, and smell what’s around you – depends on your nervous system. So does your ability to recognize where you are and to remember if you’ve been there before. In fact, your very capacity to wonder how you know where you are depends on your nervous system.
If your perceptions indicate danger, your ability to act on that information also depends on your nervous system. In addition to letting you consciously process the threat, your nervous system triggers involuntary responses, like an increase in heart rate and blood flow to your muscles, intended to help you cope with danger.
All of these processes depend on the interconnected cells that make up your nervous system. Like the heart, lungs, and stomach, the nervous system is made up of specialized cells. These include nerve cells (or neurons) and glial cells (or glia). Neurons are the basic functional units of the nervous system, and they generate electrical signals called action potentials, which allow them to quickly transmit information over long distances. Glia are also essential to nervous system function, but they work mostly by supporting the neurons.