An axon is a long, thin part of a nerve cell that carries electrical signals away from the cell's center to other cells in your body. Think of it like a wire connecting one part of your body's communication network to another.

Your brain and nervous system work because billions of nerve cells (called neurons) constantly send messages to each other and to your muscles and organs. Each neuron has a central body where it processes information, and extending from that body is usually one axon that can stretch surprisingly far. Some axons in your body are microscopic, while others run all the way from your spine down to your toes, nearly a meter long!

When you decide to wiggle your finger, electrical signals zip down axons from your brain, through your spinal cord, and out to the muscles in your hand. The signal travels along the axon like electricity through a wire, though it works differently from household electricity. At the end of the axon, the signal passes to the next cell, continuing the message chain.