How Your Brain Sends Messages

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The nervous system is your body's message network — the brain, spinal cord, and nerves working together to carry fast electrical signals between every part of you. Right now it is telling your heart to beat, your lungs to breathe, and your hand to move, all without you having to think about it.

Messages travel along special cells called neurons, which are shaped like tiny trees with long branches. A signal jumps from one neuron to the next like a spark passing down a line of friends holding hands, racing along the spinal cord — a thick cable of nerves that links the brain to the rest of the body. Some messages go up to the brain, such as "ouch, that's hot!", while others come down from the brain, such as "wave your hand!".

Learners will grasp what neurons are, how signals travel through the brain and spinal cord, the two-way flow of nerve messages, and why reflexes let the spinal cord react to danger before the brain even decides.

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Frequently asked questions

What is the nervous system?
The nervous system is the body's message network, made up of the brain, spinal cord, and nerves. It carries fast electrical signals that control everything from moving your muscles to feeling a touch.
What is a neuron?
A neuron is a special cell that carries nerve messages. It is shaped a bit like a tree with long branches, and signals pass from one neuron to the next to move a message through the body.
What does the spinal cord do?
The spinal cord is a thick cable of nerves that runs down your back and connects the brain to the rest of the body. Messages travel up and down it, like traffic on a two-way highway.
Why do reflexes happen so fast?
Some messages are so urgent that they don't wait for the brain to decide. When you touch something hot, your spinal cord sends the "pull away!" signal straight to your muscles, which is why your hand jerks back before you even feel the pain.
How do nerve messages travel through the body?
Nerve messages travel as tiny electrical signals that jump from neuron to neuron. They flow between the brain, the spinal cord, and the nerves — some going up to the brain and some coming back down to the body.

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