JOAN CARTAN-HANSEN, HOST: INSIDE

YOUR SKULL IS THE THING THAT

CONTROLS EVERYTHING YOU DO.

YOUR BRAIN.

FIND OUT MORE.

OH, WAIT A MINUTE.

YOU'RE GOING TO NEED THIS.

I'LL PUT IT BACK AND WE CAN GET

STARTED WITH THE SHOW.

(MUSIC)

THE BRAIN WEIGHS ABOUT

THREE POUNDS.

ITS MADE UP OF 100 BILLION NERVE

CELLS OR NEURONS.

ELECTRICAL MESSAGES PASS FROM

CELL TO CELL.

MESSAGES GO OUT OF YOUR BRAIN,

DOWN YOUR SPINAL CORD AND OUT TO

YOUR BODY AND THEN BACK AGAIN,

ALL IN AN INSTANT.

THE BRAIN, THE SPINAL CORD AND

ALL THOSE NERVES MAKE UP THE

NERVOUS SYSTEM.

IT'S YOUR BODY'S INFORMATION

SYSTEM.

THE BRAIN IS MADE UP OF SEVERAL

PARTS.

THERE 'S THE BRAIN STEM.

IT CONTROLS YOUR BODY'S BASIC

AUTOMATIC FUNCTIONS, LIKE

BREATHING.

THE CEREBELLUM CONTROLS THINGS

LIKE YOUR MOVEMENT, YOUR

PHYSICAL SKILLS.

AND THEN THERE IS THE LIMBIC

SYSTEM THAT IS IMPORTANT FOR

EMOTION, MEMORY AND LEARNING.

IT MAKES UP ABOUT ONE FIFTH OF

YOUR BRAIN.

THERE STRUCTURES LIKE THE

PITUITARY AND HYPOTHALAMUS.

THEY WORK WITH THE BRAIN STEM TO

CONTROL BODY TEMPERATURE, GROWTH

AND BLOOD PRESSURE.

AND THEN THERE'S THE CEREBRUM.

THIS IS THE THINKING, CREATIVE

PART OF YOUR BRAIN.

IT'S ALSO THE BIGGEST PART OF

YOUR BRAIN.

ALONG WITH ITS THIN COVERING,

THE CORTEX, IT'S THE PART OF

YOUR BRAIN THAT GOVERNS

VOLUNTARY MOVEMENTS.

ITS WHERE YOU THINK, WHERE YOU

PERCEIVE OR SENSE THINGS.

AND BECAUSE OF YOUR CORTEX, YOU

CAN UNDERSTAND, LEARN, REMEMBER

COMMUNICATE AND CREATE.

THE BRAIN'S SURFACE IS COVERED

WITH WRINKLES AND GROOVES.

THESE WRINKLES AND FOLDS ALLOW

THE BRAIN TO HAVE A MUCH LARGER

SURFACE AREA.

AND A BRAIN WITH MORE SURFACE

AREA CAN PROCESS MORE

INFORMATION.

STUDENT: IT'S KIND OF LIKE

TRYING TO TAKE A PIECE A PAPER

AND FIT IT INTO A PLASTIC EASTER

EGG.

IF IT'S FLAT IT WON'T FIT VERY

WELL.

BUT IF YOU CRUMPLE IT UP,

(CRUMPLING PAPER)

IT FITS NICELY.

AND THAT'S HOW YOUR BRAIN CAN

USE A LOT OF SURFACE AREA FOR

PROCESS POWER AND STILL FIT

INSIDE YOUR HEAD.

CARTAN-HANSEN: THE BRAIN HAS TWO

HEMISPHERES AND THERE IS BAND OF

FIBERS BETWEEN THE TWO PARTS OR

HEMISPHERES OF THE BRAIN SO THAT

THE LEFT SIDE KNOWS WHAT THE

RIGHT SIDE IS DOING.

STUDENT: THE HUMAN BRAIN IS SO

SOFT THAT YOU COULD CUT IT WITH

A BUTTER KNIFE.

THAT'S WHY YOU SHOULD WEAR YOUR

HELMET WHEN YOU RIDE YOUR BIKE.

YOU NEED TO PROTECT YOUR BRAIN!

CARTAN-HANSEN: YOUR BRAIN AND

BODY ALSO PUT OUT CHEMICALS

CALLED HORMONES OR

NEUROTRANSIMTERS.

HORMONES HELP REGULATE YOUR

BODY'S GROWTH, HELP YOU MATURE,

MAINTAIN DIGESTION, EVEN TELL

YOU WHEN TO SLEEP.

NEUROTRANSMITTERS ARE CHEMICALS

THAT SEND MESSAGES BETWEEN BRAIN

CELLS OR NEURONS.

SOME NEUROTRANSMITTERS TELL YOUR

HEART TO BEAT OR YOUR LUNGS TO

BREATHE OR MUSCLES TO MOVE WHILE

OTHERS REGULATE YOUR FEELINGS,

ATTENTION, OR BEHAVIOR.

THESE CHEMICALS PLAY A PART IN

HOW YOU REMEMBER THINGS.

WHY YOU DREAM, WHO YOU ARE.

EVERYTHING THAT HAPPENS IN YOUR

BODY, YOUR THOUGHTS, YOUR

FEELINGS, YOUR BREATHING, YOUR

GROWING ARE ALL CONTROLLED BY

YOUR BRAIN.

AND THE BRAIN CONTINUES TO

DEVELOP EVEN AFTER YOU'RE BORN.

AND IT CONTINUES TO CHANGE EVEN

AS AN ADULT.

YOUR BRAIN IS WHAT MAKES YOU,

YOU.

IF YOU WANT TO LEARN MORE ABOUT

THE BRAIN AND LOTS OF OTHER

SCIENTIFIC TOPICS, CHECK OUT THE

SCIENCE TREK WEBSITE.

YOU'LL FIND IT AT

IDAHOPTV.ORG/SCIENCE TREK

(MUSIC)

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GREAT STATE OF IDAHO; BY THE

IDAHO NATIONAL LABORATORY,

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FRIENDS OF IDAHO PUBLIC

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