What are neurons?

Dr. William B. Salt, MD

The cells of your nervous system are called neurons. Your brain has approximately one hundred billion (100,000,000,000) neurons, and each neuron makes approximately 1000 connections with other neurons. Neurons have specialized projections called dendrites and axons.

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Neurons are nerve cells in the brain. There are millions of neurons in the brain. Neurons communicate with each other by sending electrical signals that travel in the nervous system. The nervous system is a network of neurons in your whole body. For example, when people move a leg, an electrical signal travels from their brain, through their nervous system, and down to the muscle in that leg. The signal tells the muscle to move and so the leg moves. The signals can travel in the opposite direction, too, so people's vision, hearing, and sensations can tell their brain what’s going on. So if people hold ice in their left hand, for example, signals travel along their neurons to tell their brain that their left hand feels cold.

Dr. Mehmet Oz, MD
Cardiologist (Heart Specialist)

You have 100 billion neurons in your brain, which, if stretched out in length, would reach 30,000 miles. Each of these nerve cells transmits information to another neuron so that your body can perform. Neurons hold the information, but unless it's communicated to another neuron, it's virtually useless.

That's where neurons' edges come into play. They're called dendrites-and they're like baseball catchers. They receive the pitch sent to them from other neurons. Even more importantly, they act like catchers by communicating to all the other players on the field. Specifically, the dendrite can influence how the signal is sent, received, and transmitted to other neurons.

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The neuron is the brain's basic unit for processing information. The human brain contains an incredible number of neurons—about 100 billion, give or take 10 billion. The neuron is a unique cell in activity and appearance. It generates both electrical and chemical signals, making it able to communicate quickly with distant neurons. Instead of the compact shape typical of other cells in the body, the neuron is like an oak tree with giant branches stretched out. Each neuron has a body containing a nucleus, one long fiber called an axon, and many shorter branching fibers called dendrites.

Neurons—the nerve cells of the brain—carry information that allows us to act, think, learn, and feel. The best way to think of a neuron is to think of a tree, with a strong root structure and branches. The roots (or dendrites) receive information from other neurons, send that information through the trunk of the cell and out to the branches.

Those branches pass the message to the roots of another neuron, like a game of telephone. Between the branches of one neuron and the roots of the next lies a space called a synapse. When information is passed from one neuron to the next, a chemical messenger called a neurotransmitter crosses that space. Establishing and reinforcing connections between neurons is the key to learning and brain development.

While neurons are formed after birth only rarely, the dendrites continue thickening after birth into a dense forest of connections, in response to whatever stimuli a baby is exposed to.

Continue Learning about Neurons

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.