D4K: The Nervous System


Uploaded by IdahoPTV on 18.12.2012

Transcript:
>>> PRESENTATION OF D4K ON IDAHO PUBLIC TELEVISION IS MADE
POSSIBLE THROUGH THE GENEROUS SUPPORT OF THE LAURA MOORE
CUNNINGHAM FOUNDATION, COMMITTED TO FULFILLING THE
MOORE FAMILY LEGACY OF BUILDING THE GREAT STATE OF IDAHO.
>> HOW DO YOU PERCEIVE THE WORLD?
YOU USE YOUR NERVOUS SYSTEM.
BRAIN, NERVES AND ALL OF YOUR SENSES WORK TOGETHER.
WANT TO FIND OUT HOW?
WE'RE STANDING BY TO ANSWER YOUR QUESTIONS.
STAY TUNED.
D4K IS NEXT.
>> I'M JOAN CARTAN-HANSEN, WELCOME TO D4K, THE PLACE FOR
SCIENCE.
WELCOME TO THE DISCOVERY CENTER OF IDAHO AND THE BODIES
REVEALED EXHIBIT.
BEFORE WE ANSWER YOUR QUESTIONS, LET'S LEARN A LITTLE
MORE ABOUT THE NERVOUS SYSTEM.
>>> THE NERVOUS SYSTEM IS THE BODY'S WIRING, A NETWORK THAT
STRETCHES FROM OUR BRAIN ALL THE WAY TO OUR TOES.
THE NERVOUS SYSTEM IS DIVIDED INTO THREE PARTS.
THE CENTRAL NERVOUS SYSTEM INCLUDES THE BRAIN AND THE
SPINAL CORD.
THE SPINAL CORD IS A BUNDLE OF NERVE CELLS STARTING AT
THE BASE OF THE BRAIN.
AND IT'S PROTECTED BY THE VERTEBRAS OF YOUR BACK BONE.
THE NEXT PART IS THE PERIPHERAL NERVOUS SYSTEM.
THERE ARE 31 PAIRS OF NERVES COMING OUT BETWEEN THE
VERTEBRAS INTO THE BODY.
THEY BRANCH OUT THROUGHOUT THE WHOLE BODY.
ALL YOUR SENSORY ORGANS, YOUR EYES, EARS, NOSE, SKIN, AND
TONGUE ALL FEED INFORMATION TO THE BRAIN THROUGH THE
PERIPHERAL NERVOUS SYSTEM.
AND THE THIRD PART IS THE AUTONOMIC NERVOUS SYSTEM.
THIS SYSTEM DEALS WITH THE INVOLUNTARY ACTIONS OF OUR
BODY.
THINGS LIKE BREATHING, YOUR HEART BEATING, OR EVEN
DIGESTING FOOD.
>> IT'S CALLED THE AUTONOMIC OR INVOLUNTARY SYSTEM BECAUSE YOU
DON'T HAVE TO THINK ABOUT IT, YOUR BRAIN AND NERVES JUST KEEP
YOUR BODY FUNCTIONING.
>> THE NERVOUS SYSTEM IS MADE UP OF MORE THAN 100 BILLION
NERVE CELLS.
EACH CELL HAS THREE MAIN PARTS.
THE CELL BODY OR NUCLEUS.
DENDRITES, LONG THIN BRANCHES THAT GROW OUT OF THE CELL BODY.
AND AXONS, SLIGHTLY LONGER THAN THICKER BRANCHES THAT
ALSO COME OUT OF THE CELL BODY.
A MESSAGE OR IMPULSE MOVES BETWEEN CELLS.
THIS ELECTRICAL CHARGE TRAVELS INTO CELL BODY VIA THE
DENDRITES AND OUT OF THE CELL BODY THROUGH THE AXONS.
NERVE CELLS ARE SEPARATED BY TINY GAPS CALLED SYNAPSES.
WHEN AN ELECTRICAL IMPULSE REACHES THE SYNAPSES, THE
CELLS RELEASE A CHEMICAL KNOWN AS NEUROTRANSMITTER.
THE MESSAGE JUMPS OR FLOWS ACROSS THE GAP WITH THE
NEUROTRANSMITTER TO SPECIAL LANDING SITES KNOWN AS
RECEPTORS.
>> JUST LIKE A RELAY RACE.
NERVE CELLS PASS IMPULSES FROM ONE CELL TO THE NEXT.
>> AND NERVE CELLS ARE REALLY FAST.
IT ONLY TAKES ABOUT ONE- THOUSANDth OF A SECOND FOR A
MESSAGE TO JUMP FROM CELL TO CELL.
>> WHILE YOUR BRAIN GENERALLY CONTROLS A LOT OF WHAT'S GOING
ON IN YOUR NERVOUS SYSTEM, IT DOESN'T CONTROL THE BODY'S
EVERY MOVEMENT.
IF YOU TOUCH SOMETHING HOT, THE SENSORY NERVE CELLS SEND
A SIGNAL TO THE MUSCLES TO TELL THEM TO MOVE.
>> OUCH!
>> THAT AUTOMATIC MOVEMENT IS CALLED A REFLEX REACTION.
DIFFERENT NERVE CELLS DO DIFFERENT THINGS IN YOUR BODY.
SOME DETECT CHANGES IN LIGHT SO YOU BLINK.
OR SMELLS SO YOU SNIFF.
OR TASTE SO YOU LICK.
OR SOUND SO YOU HEAR.
OR TEMPERATURES SO YOU SWEAT.
OR PRESSURE SO YOU MOVE.
>> YOU HAVE MORE THAN A MILLION STRETCH SENSORS IN OUR JOINTS,
MUSCLES, SKIN AND NERVES TO CONSTANTLY MONITOR YOUR BODY
POSITION.
YOUR NERVOUS SYSTEM NEVER RESTS.
AND UNLIKE OTHER CELLS, THE BODY'S NERVES RARELY GET
REPAIRED OR RENEWED IF DAMAGED.
SO TAKE CARE OF YOUR NERVOUS SYSTEM AND IT WILL TAKE CARE
OF YOU.
Captioning Performed by DLR
>> Dr. a neurologist at Saint Alphonsus hospital in Boise.
thank you for being here.
>> you're welcome.
>> let's go to the questions.
>> why are nerves so important to our body?
>> the simplest explanation, or most OBvy would be your
eyeballs, you need your nerves to sense what's going on around
you.
in addition, your nerves tell your body and brain where you
are, where you are standing or sitting.
also tell your heart to speed up or slow down.
nerves tell your brain when you are full.
and nerves to the bladder tell your brain when you have to go
to the bathroom.
very important for ever part of our functioning.
>>
>> IF YOU REALLY INJURED IT AND FOR SEVERAL DAYS IT IS BUZZING,
AND THEN IT IS -- THERE HAS BEEN A BRUISE OF THE COATING
AND IT CAN HEAL.
IF YOU ACTUALLY INJURE THE AXON ITSELF OR THE WIRE PART, MOST
OF THE TIME IT DOESN'T REGROW.
>> HENRY WOULD LIKE TO KNOW WHAT DOES THE NERVOUS SYSTEM
LOOK LIKE?
>> WELL, HENRY, IF YOU LOOK AT THE NERVOUS SYSTEM GROSSLY OR
JUST WITHOUT ANY KIND OF COVERING OR JUST WITH THE NAKED
EYE, IT WOULD LOOK WHITISH AND A LOT LIKE FIRM JELLO.
IF YOU LOOKED AT IT MICROSCOPIC MICROSCOPICAL
MICROSCOPICALLY, YOU WOULD SEE BUNDLES OF NERVES COMING UP AND
GOING DOWN, AND I THINK THAT IT WOULD LOOK A LOT LIKE TO YOU
LIKE ELECTRICAL CORDS THAT ARE BUNDLED TOGETHER.
>> HI, MY NAME IS HARRISON.
HOW FAST DOES IT TAKE FOR YOUR BRAIN TO RECOGNIZE THAT YOU GOT
HURT?
>> WELL, HARRISON, THE PAIN FIBERS, FIBERS, NERVE FIBERS
THAT SENDS DISCOMFORT OR PAIN, THEY TRANSMIT MESSAGES VERY,
VERY QUICKLY IN ORDER TO KEEP YOU FROM BEING HURT.
SO, IF YOU -- IF YOU TOUCH A HOT PAN, THEN THOSE NERVES
TRAVEL VERY, VERY QUICKLY IN ORDER TO GET YOU TO PULL YOUR
HAND AWAY FROM THE PAN AS SOON AS POSSIBLE AND AVOID FURTHER
INJURY.
THEY WOULD BE IN THE THE 200 MILES PER HOUR RANGE.
>> WHY DO NERVES RESPOND SO FAST?
>> NERVES RESPOND QUICKLY IN ORDER TO KEEP YOU OUT OF
DANGER.
IF YOU STEP ON A -- IF YOU TOUCH A TACK OR YOU STEP ON A
TACK, THEN THE NERVE THAT -- THAT YOU STIMULATED BY DOING
THAT HAS TO TRAVEL VERY QUICKLY UP TO THE BRAIN IN ORDER TO
KEEP YOU FROM COMPLETELY STEPPING ON IT.
AND THEN SEND THE SIGNAL BACK DOWN TO GET YOU TO PULL YOUR
FOOT BACK UP OFF OF THAT TACK.
IT IS TO KEEP YOU OUT OF DANGER.
>> MY NAME IS GRANT.
MY QUESTIONS WHY WHEN YOU HARM A NERVE, IT DOESN'T
REGENERATE?
>> SOME NERVES DO REGENERATE, AND IN THE PERIPHERAL NERVOUS
SYSTEM AND IN THE ARMS AND LEGS, IF A NERVE IS INJURED, IT
CAN SOMETIMES REGROW IF IT HAS NOT BEEN INJURE TOO SEVERELY,
AND MOST OF THE TIME THEY DON'T.
THE NUMBER WE'RE BORN WITH IS THE NUMBER WE GET AND THAT IS
IT.
YOU HAVE TO TAKE GOOD CARE OF THEM.
>> MY NAME IS COOPER.
AND MY QUESTION IS, DOES THE NERVOUS SYSTEM CREATE FEAR?
>> THE NERVOUS SYSTEM DOESN'T CREATE FEAR.
IT RESPOND TO FEAR.
SO, IF YOU ARE WALKING IN THE WOODS AND A BEAR SHOWS UP, THEN
YOUR BRAIN -- THE EYES SEE THE BEAR AND THEN THAT SENDS A
MESSAGE TO THE REST OF THE BRAIN AND THEN THE BRAIN
RESPOND TO THAT STIMULATION.
IT DOESN'T CREATE FEAR, IT JUST REACTS TO IT.
>> HI, I'M MADDY, AND I WANT TO KNOW WHAT MAKES PEOPLE
TICKLISH.
>> THAT IS A VERY GOOD QUESTION.
AND I DON'T KNOW IF THERE IS A SPECIFIC ANSWER TO THAT.
I BELIEVE THAT THE THOUGHT IS THAT TICKLISH AREAS TEND WHAT
WOULD BE CALLED VULNERABLE AREAS, LIKE THE BOTTOMS OF YOUR
FEET, UNDER YOUR ARMS.
IT IS IMPORTANT THAT THEY WOULD KNOW IF SOMETHING WAS GOING TO
HAPPEN TO THEM IN ORDER TO WITHDRAW OR PROTECT OR ELSE
JUST FUN, I'M NOT REALLY SURE.
>> MY NAME IS WESLEY.
THE QUESTION I'M ASKING IS WHY DOES IT HURT SO MUCH WHEN YOU
HURT YOUR ELBOW?
>> WELL, IT IS NOT FUNNY, EVEN THOUGH IT IS CALLED A FUNNY
BONE, IT IS NOT FUNNY.
THE ULNA NERVE, THE NERVE THAT GOES TO THE PINKY FINGER AND
HALF OF THE RING FINGER, TRAVELS THROUGH A BONY CANAL ON
THE ELBOW BONE, AND IN THAT GROOVE OF THAT BONE OF THE
ELBOW BONE, IF YOU BANG IT, IT DOESN'T HAVE A LOT OF
PROTECTION.
AND YOU ACTUALLY BRUISE THE NERVE.
BRIEFLY AND TEMPORARILY OR FOR A LITTLE LONGER, YOU ACTUALLY
BRUISE OR SHOCK THE NERVE >> ABBY WOULD LIKE TO KNOW CAN
YOUR NERVES SOMETIMES VIBRATE YOUR EYES?
>> YES, ABBY, THEY CAN.
THERE ARE SEVERAL DIFFERENT WAYS THAT THE BRAIN -- THE
BRAIN CAN DO THAT IF THERE IS A MISWIRING IN THE BRAIN.
YOU GET THE EYE JERKING BACK AND FORTH, AND IF A PERSON IS
VERY DIZZY, THEN THE EYES CAN JERK BACK AND FORTH.
THE OTHER THING YOU MIGHT BE THINKING OF IS THE MUSCLE THAT
GOES AROUND THE EYE CAN TWITCH, USUALLY WITH STRESS.
>> MY QUESTION IS HOW DOES THE BRAIN TELL THE DIFFERENT
MUSCLES WHEN TO MOVE?
>> WELL, THERE IS A SEQUENCE OF EVENTS, MOVE YOUR FINGER OR
YOUR TOE, YOU THINK THE THOUGHT, THE THOUGHT IS
TRANSMITTED FROM THE BRAIN DOWN TO THE SPINAL CORD.
ANOTHER NERVE PICKS UP THAT IMPULSE AND TAKES IT OUT TO THE
MUSCLES AND THAT SECOND NERVE DUMPS A CHEMICAL ON THE MUSCLE
THAT CAUSES IT TO CONTRACT.
A THOUGHT, A PROCESS, AND THEN A CHEMICAL.
>> HI, MY NAME IS HEATHER.
AND I WANT TO KNOW HOW -- >> WELL, HEATHER, EATING
HEALTHY FOOD HELPS YOUR ENTIRE BODY AS WELL AS YOUR NERVOUS
SYSTEM.
THERE ARE CERTAIN VITAMINS THAT YOUR BRAIN NEEDS.
B-VITAMINS REALLY GOOD FOR YOUR BRAIN AND YOUR NERVES AND
PROTEIN IS REALLY GOOD BUT EATING HEALTHY JUST HELPS
EVERYTHING.
>> HI, AND I WANT TO KNOW HOW LONG IS A NERVE?
>> THERE ARE DIFFERENT NERVES.
IF YOU THINK ABOUT THE NERVE THAT WOULD GO FROM THE TIP OF
YOUR TOE UP TO YOUR SPINAL CORD, THAT WOULD BE SEVERAL
FEET LONG.
VERSUS A NERVE THAT GOES FROM YOUR EYEBALL TO YOUR BRAIN
MIGHT BE A FAIRLY SHORT NERVE.
>> MY NAME IS ELLIE, AND MY QUESTION IS, DO DIFFERENT
NERVES REACT TO DIFFERENT THINGS?
>> YES, THEY DO.
YOU HAVE NERVES THAT REACT TO PAIN.
AND TO TEMPERATURE.
AND TO LIGHT TOUCH.
AND YOU HAVE -- AND THOSE WOULD BE THE NERVES THAT IF YOU WERE
TO STEP ON HOT CEMENT OR ON TO A TACK, THOSE ARE THE NERVES
THAT WOULD SEND THE IMPULSE OR MESSAGE UP TO THE BRAIN AND
THEN YOU HAVE NERVES THAT ARE MORE LOCATED IN JOINTS THAT ARE
PRESSURE RECEPTORS, AND THOSE TELL YOUR BRAIN UNCONSCIOUSLY
THAT YOU HAVE MOVED OR SHIFTED OR YOU STARTED TO LEAN IN ONE
DIRECTION, SO THOSE ARE MOSTLY UNCONSCIOUS NERVES THAT ARE
PART OF HOW WE ARE ABLE TO STAND UP.
>> THE BRAIN, IT'S PROBABLY THE MOST IMPORTANT PART OF THE
NERVOUS SYSTEM.
LET'S LEARN A LITTLE BIT MORE ABOUT THE BRAIN.
>> THE BRAIN WEIGHS ABOUT THREE POUNDS.
IT IS MADE UP OF 100 BILLION NERVE CELLS OR NEURONS.
ELECTRICAL IMPULSES PASS FROM CELL TO CELL.
MESS SANGS GO OUT OF YOUR BRAIN, DOWN THE SPINAL CORD --
THE BRAIN, SPINAL CORD, ALL OF THE NERVES MAKE UP THE NERVOUS
SYSTEM.
IT IS YOUR BODY'S INFORMATION SYSTEM.
>> TO TURN ON A LIGHT IN THE REFRIGERATOR --
>> THE BRAIN IS MADE UP OF SEVERAL PARTS.
THERE IS THE BRAIN STEM, IT CONTROLS YOUR BODY'S BASIC
AUTOMATIC FUNCTIONS LIKE BREATHING, THE CEREBELLUM,
CONTROLLING THINGS LIKE MOVEMENT, PHYSICAL SKILLS, AND
THE SYSTEM THAT MAKES UP ABOUT ONE FIFTH OF THE BRAIN.
GLANDS, THEY WORK WITH THE BRAIN STEMS TO CONTROL BODY
TEMPERATURE, GROWTH, BLOOD PRESSURE.
THEN THE THINKING CREATIVE PART OF YOUR BRAIN, THE BIGGEST PART
OF THE BRAIN.
ALONG WITH THE THIN COVERING, CORTEX, COVERS VOLUNTARY
MOVEMENTS, WHERE YOU THINK, PERCEIVE, SENSE THINGS, AND
BECAUSE OF YOUR CORTEX, YOU CAN UNDERSTAND AND REMEMBER,
COMMUNICATE AND CREATE.
THE BRAIN HAS TWO SIDES.
EACH CONTROLS THE OPPOSITE SIDE OF THE BODY.
EACH SIDE ALSO CONTROLS CERTAIN SKILLS.
RIGHT SIDE OF YOUR BRAIN CONTROLS MUSIC AND ART,
CREATIVE STUFF AND THE LEFT SIDE HANDLES NUMBERS AND WORDS
AND PROBLEM SOLVING, AND THERE IS A BAND OF CELLS BETWEEN THE
TWO PARTS, HEM -- >> THE HUMAN BRAIN IS SO SOFT
THAT YOU COULD CUT IT WITH A BUTTER KNIFE.
THAT IS WHY YOU SHOULD WEAR YOUR HELMET WHEN YOU RIDE YOUR
BIKE.
YOU NEED TO PROTECT YOUR BRAIN.
>> BRAIN AND BODY PUT OUT CHEMICALS, HORMONES OR
NEUROTRANSMITTERS.
HELP REGULATE YOUR BODY'S GROWTH, MATURE, MAINTAIN
DIGESTION AND TELL YOU WHEN TO SLEEP.
NEUROTRANSMITTERS SEND MESSAGES BETWEEN CELLS.
TELL YOUR HEART TO BEAT OR LUNGS TO BREATHE.
OTHERS REGULATE YOUR MOOD, WHETHER YOU ARE HAPPY OR SAD.
THESE CHEMICALS PLAY A PART IN HOW YOU REMEMBER THINGS.
WHY YOU DREAM, WHO YOU ARE, AND YOUR THOUGHTS AND YOUR
FEELINGS.
YOUR BREATHING AND YOUR GROWING ARE ALL CONTROLLED BY YOUR
BRAIN.
AND YOUR BRAIN CONTINUES TO DEVELOP EVEN AFTER YOU ARE BORN
AND CONTINUES TO GROW AND CHANGE EVEN AS AN ADULT.
YOUR BRAIN IS WHAT MAKES YOU, YOU.
>> HI, MY NAME IS RYAN, AND I WANT TO KNOW HOW --
>> THERE ARE DIFFERENT PHASES OF MEMORY, THERE IS IMMEDIATE
MEMORY, AND THEN THERE IS SHORT-TERM MEMORY, AND THEN
THERE IS LONG-TERM MEMORY.
AND THE -- THE BRAIN AND -- YOUR CONSCIOUSNESS AND YOUR
FAMILY AND YOUR GENETICS TEND TO DETERMINE WHETHER YOU LAY A
SHORT-TERM MEMORY DOWN AS A LONG-TERM MEMORY, AND THAT IS
ALL IN A PART OF THE BRAIN CALLED THE HIPPOCAMPUS.
>> CORY, AND I WANT TO KNOW WHY DOES THE BRAIN NEED A LOT OF
ENERGY?
>> WELL, IF YOU THINK ABOUT IT, THE BRAIN IS CONTINUOUSLY
WORKING, EVEN WHEN YOU ARE SLEEPING, YOUR BRAIN IS
WORKING, MAKING DREAMS AND PROCESSING THINGS THAT HAPPEN
DURING THE DAY.
AND THOSE CELLS USE UP A LOT OF GLUCOSE AND THEY USE UP A LOT
OF OXYGEN.
SO THE -- THE BRAIN NEEDS A LOT OF ENERGY.
>> CRAIG AND I WOULD LIKE TO KNOW HOW DO NERVES SEND MESSAGE
MESSAGES TO YOUR BRAIN?
>> THERE ARE TWO -- MOTOR NERVES GO FROM THE BRAIN AND
THE SPINAL CORD OUT TO THE MUSCLE AND THEN THERE IS
SENSORY NERVES THAT LEAD FROM YOUR SKIN AND YOUR JOINTS INTO
THE NERVOUS SYSTEM.
ONE GOES OUT AND ONE KIND COMES IN.
AND THERE ARE -- THEY ARE LIKE ELECTRICAL CORDS.
THERE IS A WIRE OR AN AXON THAT CARRIES THE ELECTRICAL MESSAGE
AND THEN THERE IS A COATING AROUND THE NERVE THAT KEEPS THE
ELECTRICAL IMPULSE INSIDE.
AND SO, YOUR NERVOUS SYSTEM, PERIPHERAL NERVOUS SYSTEM, A
LOT LIKE BUNDLES OF ELECTRICAL WIRES.
>> HI, AND I WANT TO KNOW DOES EACH PART OF THE BRAIN DO?
>> WELL, JENNY, THERE ARE SEVERAL DIFFERENT LOBES OF THE
BRAIN.
FRONTAL LOBES IN THE FRONT OF THE BRAIN ARE INVOLVED WITH
INITIATING ACTIVITY OR STARTING UP AN ACTIVITY.
ALSO CONTROL OF BEHAVIOR.
THE OCCIPITAL LOBES IN THE WAY BACK OF THE BRAIN ARE WHERE WE
INTERPRET WHAT WE SEE GOES TO THE BACK OF THE BRAIN, AND THEN
IN MOST PEOPLE, THE LEFT SIDE OF THE BRAIN IS WHERE SPEECH
SAN THE RIGHT SIDE OF THE BRAIN IS WHERE LOCALIZATION OR WHERE
THINGS ARE.
CHLOE WOULD LIKE TO KNOW HOW DOES YOUR BRAIN CONTROL WHAT
YOU SMELL?
>> WELL, THE BRAIN INTERPRETS WH -- WHAT YOU SMELL.
CHEMICALS IN THE AIR THAT GO UP YOUR NOSE, LAYER ON THE
OLFACTORY NERVE, SMELLING NERVE, AND THEN IT TRIGGERS
DIFFERENT RECEPTORS AND THEN THE BRAIN INTERPRETS IT BASED
ON WHAT IT SMELLED BEFORE.
>> HI, MY NAME IS NIA, AND MY QUESTION IS WHAT HAPPENS TO
YOUR BRAIN WHEN YOU GET A CONCUSSION?
>> THE BRAIN HAS A SKULL, THE SKULL IS A PROTECTION FOR THE
BRAIN.
THE BRAIN IS SOFT.
IT IS SIMILAR TO THE CONSISTENCY OF OLD JELLO.
SO THE BRAIN HAS TO HAVE THE SKULL AROUND IT TO PROTECT IT.
BUT IF THE SKULL HITS A HARD ENOUGH OBJECT, THEN THE BRAIN,
WHICH IS SUSPENDED IN FLUID -- THERE IS FLUID ALL OF THE WAY
AROUND THE BRAIN, BUT IF THE SKULL HITS A HARD OBJECT, THEN
THE BRAIN KIND OF ROCKETS BACK AND FORTH INSIDE THE SKULL AND
IT BRUISES ITSELF.
AND THAT IS AN A CONCUSSION.
>> HI, AND I WANT TO KNOW WHAT --
>> ANDREW, THAT DOES DEPENDS ON WHAT DRUGS WE ARE TALKING
ABOUT.
MOST PRESCRIPTION DRUGS HAVE VERY LITTLE EFFECT ON THE
CENTRAL NERVOUS SYSTEM OR A SPECIFIC EFFECT THAT IS A GOOD
THING, LIKE AN ANTISEIZURE MEDICATION.
DRUGS LIKE ALCOHOL OR MARIJUANA OR VALIUM, THEY TEND TO SEDATE
THE BRAIN AND DRUGS LIKE COCAINE OR METHAMPHETAMINE TEND
TO STIMULATE THE BRAIN.
IT DEPENDS ON WHICH DRUG WE'RE TALKING ABOUT.
>> WHAT HAPPENS TO YOUR NERVES WHEN YOU GET FROSTBITE?
>> WELL, IRIS, FROSTBITE OCCURS WHEN YOU ARE IN TOO COLD OF A
SITUATION, AND THE BODY NEEDS TO MAINTAIN ITS WARMTH AND IT
TENDS TO KEEP THE WARM BLOOD MORE CENTRALLY SO YOUR INTERNAL
ORGANS ARE MORE PROTECTED, INSULATED AGAINST THE COLD.
FINGERS AND THE TOES AND YOUR EARS WOULD NOT BE QUITE SO WELL
INSULATED, AND IF YOU CANNOT MAINTAIN THE WARMTH AGAINST THE
COLD ROOM THAT YOU ARE IN OR COLD PLACE YOU ARE IN, THEN THE
FINGERTIPS AND TOES START TO FREEZE AND THE ITISSUES FREEZE
AND -- >> HI, I WANT TO KNOW DO OTHER
ANIMALS HAVE NERVOUS SYSTEMS, TOO?
>> ALL WARM-BLOODED ANIMALS HAVE NERVOUS SYSTEMS.
NOT ALL OF THEM HAVE THE SAME SIZE OR STRUCTURE THAT WE HAVE
IN TERMS OF OUR CONSCIOUSNESS AND OUR THINKING ABILITIES.
>> DOES BEING NERVOUS AFFECT YOUR BRAIN OR HEART IN ANY WAY?
>> YES, THERE ARE TWO PARTS OF THE NERVOUS SYSTEM.
THERE IS THE SYMPATHETIC AND THE PARASYMPATHETIC, AND THE
SYMPATHETIC IS THE FIGHT OR FLIGHT RESPONSE, WHAT DO YOU DO
IF YOU SEE A BEAR?
AND YOU NEED TO TURN AROUND AND RUN.
THE SYMPATHETIC NERVOUS SYSTEM WOULD MAKE YOUR BRAIN TO GO
INTO HIGH GEAR TO THING REALLY FAST AND MAKE YOUR HEART SPEED
UP TO GET THE BLOOD TO YOUR MUSCLES SO THAT YOU COULD RUN
AWAY FROM THE BEAR.
THE PARASYMPATHETIC NERVOUS SYSTEM IS ORIENTED TOWARDS
DAY-TO-DAY JUST THINKING, SLEEPING, DIGESTING FOOD AND SO
IT SLOWS THE HEART DOWN AND IT PROBABLY WOULD RELAX THE BRAIN.
>> DID YOU KNOW THAT IF ALL OF THE NEURONS FROM A PERSON'S
NERVOUS SYSTEM WERE LINED UP IN A ROW, THAT LINE WOULD STRETCH
MORE THAN 600 MILES.
THAT IS ABOUT THE SAME DISTANCE FROM WASHINGTON, D.C., TO
CHICAGO.
>> HI, MY NAME IS REESE, AND MY QUESTION IS WHAT --
>> I DON'T KNOW THAT ANYBODY KNOWS EXACTLY WHAT CREATES AN
ITCH, BUT USUALLY IT IS SOME KIND OF INFLAMMATION OR
IRRITATION THAT THEN TRIGGERS MASS CELLS THAT PRODUCE
HISTAMINE THAT THEN STIMULATES THE FIBERS THAT MAKE YOU WANT
TO SCRATCH IT.
>> HI, MY NAME IS PRESTON.
MY QUESTION IS, IS SKIN PART OF THE NERVOUS SYSTEM?
>> THE SKIN IS NOT PART OF THE NERVOUS SYSTEM, PER SE.
IT HAS LOTS OF NERVES INTO IT.
OR THROUGH IT.
THE SKIN IS MOSTLY PROTECTION.
IT IS TO KEEP US WET INSIDE AND DRY OUTSIDE.
AND IT IS RESPONSIVE TO THE NERVOUS SYSTEM IF YOU THINK
ABOUT PEOPLE WHO BREAK OUT IN A RASH WHEN THEY'RE REALLY
NERVOUS.
IT IS RESPONSIVE TO THE NERVOUS SYSTEM, BUT NOT SPECIFICALLY A
PART OF THE NERVOUS SYSTEM.
>> HOW LARGE AROUND IS YOUR SPINAL COLUMN?
>> WELL, LAUREN, THE BRAIN IS ABOUT THIS BIG AND THEN THE
BRAIN STEM, WHICH IS THE CRANIAL NERVES, THAT PORTION OF
THE BRAIN IS QUITE A BIT SMALLER AND THE SPINAL CORD
STARTS OFF LARGER IN THE NECK AND THE CERVICAL CORD, IT IS
PROBABLY ABOUT AS BIG AROUND AS A QUARTER.
AND BY THE TIME IT GETS DOWN TO THE LUMBAR AREA, IT IS PROBABLY
ABOUT THE SIZE OF A NICKEL ALL OF THE WAY AROUND, I WOULD
GUESS.
>> I WANT TO KNOW WHAT HAPPENS TO YOUR BRAIN WHEN WE GET OLD?
>> WELL, AS -- WHEN WE ARE BORN, WE ARE BORN WITH A
CERTAIN NUMBER OF BRAIN CELLS AND WE ACTUALLY START LOSING
BRAIN CELLS THE MINUTE WHERE HE BORN, BUT WE DON'T MISS THEM
BECAUSE WE HAVE GOT 7 TRILLION AND LOTS MORE THAN WE ACTUALLY
NEED.
AS YOU GET OLDER, THOUGH, YOU DO LOSE BRAIN CELLS HERE AND
THERE.
AND IT DOES BECOME HARDER TO LEARN NEW THINGS.
AND TO HOLD ON TO MEMORIES SOMETIMES.
SO, THE BRAIN DOES SHRINK A BIT AS WE GET OLDER.
>> I HAVE A QUESTION ON HOW MANY NERVES ARE THERE IN THE
HUMAN NERVOUS SYSTEM?
>> GRACE, I THINK THAT THE THOUGHT IS THAT THERE ARE ABOUT
7 TRILLION, WHICH WOULD BE 7,000 BILLION.
THAT IS A LOT.
>> WHEN DID YOU DECIDE TO BECOME A DOCTOR AND STUDY
NEUROLOGY?
>> WELL, I WOULD SAY THAT I LIKED MATH AND SCIENCE, AND
WHEN I WAS IN COLLEGE, I BECAME INTERESTED IN PHYSIOLOGY, THE
WHYS OR HOWS OF HOW THINGS WORK.
AND THAT IS ACTUALLY PROBABLY WHERE I STARTED.
>> IF YOU WANT TO DO THIS FOR A LIVING SOME DAY, IF SOMEONE OUT
THERE WANTS TO DO THIS, WHAT CLASSES SHOULD THEY TAKE?
>> A LOT OF MATH AND SCIENCE, AND THEN ROUND YOURSELF WITH
EXERCISE AND LANGUAGES AND THE ARTS, BUT I THINK THAT THAT IS
THE MOST IMPORTANT PART.
>> I'M AFRAID WE HAVE RUN OUT OF TIME, DR. RIVER.
THANK YOU VERY MUCH FOR JOINING US.
>> YOU ARE A' WELCOME.
>> A SPECIAL THANKS TO THE DISCOVERY CENTER OF IDAHO FOR
HOSTING US.
YOU CAN LEARN MORE ABOUT THE NERVOUS SYSTEM AND OTHER
SCIENCE TOPICS ON THE D4K WEB SITE AND WE WILL ANSWER MORE
QUESTIONS ABOUT THE NERVOUS SYSTEM ON THE WEB ONLY, YOU
WILL FIND IT ALL AT idahoptv.org/D4K.
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WE WILL SEE YOU NEXT TIME ON D4K.
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