Your Brain's Secret Messages: How Signals Travel Through Your Body
Quick — touch something hot! Your hand moves away SUPER FAST before you even decide to move it. How did your body do that so quickly? Your brain sent a secret message through your body at lightning speed! Your brain and body talk to each other all the time — even right now, while you are reading this.
What You'll Learn
In this lesson you will learn: - What your brain does and where it lives - What nerves are and how they carry messages - How your brain and muscles work as a team - Why your hand pulls back from something hot before you even feel pain
Your Brain: The Boss of Your Body
Your brain lives inside your skull, at the top of your head. It is about the size of two fists held together — and it weighs about three pounds. Your brain is in charge of EVERYTHING: moving your legs, seeing with your eyes, hearing sounds, feeling hungry, having dreams, and even thinking about your favorite color right now. The brain has three big sections: - The CEREBRUM — the big wrinkly top part: thinks, remembers, and controls on-purpose movement - The CEREBELLUM — the small bumpy part at the back: helps you balance and move smoothly - The BRAIN STEM — at the bottom, connecting to your spine: controls breathing and heartbeat automatically, even while you sleep
Nerves: Your Body's Telephone Wires
Nerves are thin fibers that run from your brain, down through your spinal cord, and then out to every part of your body — your fingers, toes, nose, and tummy. Nerves carry messages in TWO directions: - FROM your body TO your brain: This floor is cold! or That smells amazing! - FROM your brain TO your body: Move your left foot! or Blink your eyes! These messages travel incredibly fast. Some nerve signals zoom along at 268 miles per hour — faster than the fastest racing car on Earth.
The quickest nerve signals travel at 268 miles per hour (about 430 kilometers per hour). That is faster than a Formula 1 race car! This is why your hand yanks back from something hot almost instantly — long before you would have time to consciously think about moving it.
How Moving Actually Works
Let's follow one brain message from start to finish: 1. Your BRAIN decides to wave hello to a friend. 2. It sends a signal down through the SPINAL CORD — the big nerve highway inside your backbone. 3. The signal travels along a NERVE from the spinal cord out to the muscles in your arm. 4. Your MUSCLES squeeze and relax in the exact right order — and your arm waves! You do this thousands of times a day without thinking about it. Walking, chewing, blinking, breathing — your brain sends millions of messages every second to keep everything working perfectly together.
Match each body part to its job in sending brain messages.
Terms
Definitions
Drag terms onto their definitions, or click a term then click a definition to match.
How fast can the fastest nerve signals in your body travel?
What does the brain stem control?
Ruler Reaction Time Test
Test how fast YOUR nerve signals really are! You need a ruler and a partner. 1. Have your partner hold a ruler vertically with the 0 cm mark at the bottom. 2. Hold your thumb and finger open right at the 0 cm mark — but do NOT touch the ruler yet. 3. Without any warning, your partner drops the ruler. 4. Catch it as fast as you can! 5. Look at where your fingers caught it. A lower number means a faster reaction time. 6. Try 5 times and write down each number. Add them up and divide by 5 to find your average. Record your results and compare with your partner. Who has the faster nerve signals today? Discuss: what do you think would happen to your reaction time if you were very tired or very hungry?
Flashcards — click each card to reveal the answer
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