JOAN CARTAN-HANSEN: HI, I'M JOAN
CARTAN-HANSEN, AND WELCOME TO

SCIENCE TREK: THE WEB SHOW.

AND WELCOME TO THE OFFICES OF
IDAHO GASTROENTEROLOGY IN

MERIDIAN.

JOINING ME NOW TO ANSWER YOUR
QUESTIONS ABOUT THE DIGESTIVE

SYSTEM ARE DR. MATTHEW SERICATI
AND DR. BRIAN STORY.

THANK YOU BOTH FOR JOINING US.

DR. BRIAN STORY: THANKS FOR
HAVING US.

DR. MATTHEW SERICATI: WE'RE GLAD
TO BE HERE.

CARTAN-HANSEN: OKAY, LET'S GO TO
YOUR QUESTIONS.

(MUSIC)

RONAN: HI, MY NAME IS RONAN.

AND I AM FROM MRS. FREELAND'S
SECOND-GRADE CLASS FROM MOSCOW,

IDAHO.

AND I WOULD LIKE TO KNOW HOW DO
YOU DIGEST YOUR FOOD?

DR. SERICATI: SO YOU DIGEST YOUR
FOOD, REALLY, WITH SEVERAL

DIFFERENT STEPS.

THE FIRST STEP STARTS WHEN YOUR
BRAIN TELLS YOU YOU'RE HUNGRY.

IT'S GOING TO TURN ON WHAT ARE
CALLED HORMONES.

HORMONES ARE SIGNALS TO YOUR
INTESTINAL TRACT TO START MOVING

BECAUSE YOU'RE GOING TO START
EATING.

ONCE YOU DO THAT, YOU START
DEVELOPING WHAT'S CALLED

"SALIVA."

SALIVA IS OTHERWISE KNOWN AS
"SPIT."

IT'S THE LUBRICATION THAT HELPS
YOUR FOOD GO DOWN FROM YOUR

MOUTH TO YOUR STOMACH.

NOW, REMEMBER, IT'S ALSO REAY
IMPORTANT TO CHEW YOUR FOOD.

AND YOUR MOM AND DAD TELL YOU
THAT ALL THE TIME, AND THEY'RE

NOT KIDDING.

THAT STARTS BREAKING FOOD DOWN.

NOW, ONCE IT GETS INTO YOUR
MOUTH, IT'S GOING TO GO DOWN

INTO YOUR STOMACH, AND IT'S
GOING TO USE COORDINATED MUSCLES

ALL THE WAY DOWN THE ESOPHAGUS
TO PUSH IT DOWN INTO THE

STOMACH.

THE OTHER THING THAT HELPS IT IS
GRAVITY.

WHEN YOU THROW A BALL UP IN THE
AIR AND IT COMES DOWN AT YOU,

SAME THING HAPPENS WHEN YOU'RE
SITTING UPRIGHT AND YOU EAT

FOOD, IT FALLS INTO YOUR STOMACH
MORE EASILY.

NOW, WHEN THE STOMACH SEES THE
FOOD, IT'S TURNING ON ITS ACID

PUMPS.

ACID PUMPS ARE REALLY GOOD AT
BREAKING FOOD DOWN BECAUSE THE

FOOD ISN'T DESIGNED TO BE IN
SUCH AN ACIDIC ENVIRONMENT.

AS THE FOOD STARTS TO BREAK
DOWN, THE STOMACH STARTS TO

RUMBLE AND GRUMBLE AND STARTS
PUSHING IT OUT OF THERE AFTER

IT'S MUSHED IT UP SOME.

SO IT MAKES THE FOOD LOOK MORE
LIKE MUSH.

AS IT PUSHES IT OUT OF THE
STOMACH, IT GOES INTO THE SMALL

INTESTINE.

NOW, THE SMALL INTESTINE LOOKS
LIKE A BUNCH OF LITTLE FINGERS,

ALSO KNOWN AS "VILLI."

THOSE VILLI ARE VERY IMPORTANT
FOR ABSORBING THE NUTRIENTS OUT

OF THE FOOD INTO YOUR SYSTEM.

AND YOU HAVE ABOUT 25 OR 30 FEET
OF THAT SMALL INTESTINE TO GET

AS MANY NUTRIENTS AS YOU CAN GET
OUT.

AS SOON AS IT HITS YOUR LARGE
INTESTINE, OTHERWISE KNOWN AS

THE "COLON," THERE'S A LOT OF
EXTRA FLUIDS IN THERE THAT THE

BODY WANTS TO TAKE BACK, SO THE
COLON'S JOB IS TO SUCK THOSE

FLUIDS BACK OUT INTO YOUR SYSTEM
SO YOU DON'T GET DEHYDRATED.

AND THEN, FINALLY, YOU'LL END UP
GOING POOP WITH THE WASTE THAT

THE BODY DIDN'T NEED WHEN YOU
ATE THE FOOD.

LIAM: MY NAME IS LIAM.

AND MY QUESTION IS WHY DOESN'T
THE ACID HURT YOUR STOMACH?

DR. STORY: ACID DOESN'T HURT OUR
STOMACH BECAUSE OUR STOMACH DO

A VERY NICE JOB OF PROTECTING
ITSELF FROM THE ACID THAT'S

WITHIN THE STOMACH AND
PREVENTING IT FROM CAUSING

INJURY.

SO WE HAVE A NUMBER OF BARRIERS,
LIKE A THICK WALL, WE HAVE A LOT

OF MUCUS.

AND THIS MUCUS LAYER CAN SPREAD
OUT AND ACTUALLY LOOK LIKE A BIG

BOOGER.

IT JUST HELPS TO PROTECT THAT
FOOD -- OR THAT ACID FROM

ATTACKING THE LINING AND CAUSING
INJURY.

OTHER THINGS THAT CAN HELP ARE
SOME OF THE ADDITIONAL FOOD WE

EAT CAN ACTUALLY PREVENT THE
ACID FROM CAUSING THAT INJURY,

AS WELL.

BRITAIN: HI, MY NAME IS BRITAIN.

AND MY QUESTION IS WHAT CAUSES
YOU TO FEEL QUEASY?

DR. STORY: FEELING QUEASY
USUALLY WILL START WHEN YOUR

STOMACH DOESN'T LIKE SOMETHING
THAT YOU ATE.

AND SOMETIMES THE STOMACH
REACTION IS TO SEND SIGNALS FROM

YOUR STOMACH TO YOUR BRAIN
SAYING, I DON'T THINK I LIKE HOW

THAT MADE ME FEEL.

THE OTHER THING THAT CAN HAPPEN
IN THE STOMACH IS RATHER THAN

SQUEEZING THINGS THROUGH INTO
THE SMALL INTESTINE, IT CAN STOP

SQUEEZING FOR A PERIOD OF TIME,
AND THEN FLUIDS AND FOOD BUILD

UP AND STAY IN THE LINING OF THE
STOMACH.

THE LINING OF THE STOMACH
DOESN'T LIKE THAT AT ALL, SO IT

STARTS SENDING SIGNALS FEELING
KIND OF CRUMMY.

RYDER: HI, MY NAME IS RYDER, AND
MY QUESTION IS WHERE DOES FOOD

GET STUCK IN YOUR THROAT WHEN
YOU CHOKE?

DR. SERICATI: SO WHEN YOU CHOKE,
THE FOOD USUALLY GETS STUCK IN

THE BACK OF YOUR MOUTH AND THE
BEGINNING PART OF YOUR ESOPHAGUS

OR SWALLOW TUBE.

AND IN THAT AREA YOU HAVE A
FANCY FLAP CALLED THE

"EPIGLOTTIS" THAT BLOCKS THE
AIRWAY FROM LETTING FOOD GO DOWN

INTO THE LUNGS.

WHEN IT GOES BACK INTO THAT
AREA, USUALLY EITHER SOME FOOD

MADE IT AROUND THAT FANCY FLAP,
AND IT GOT INTO THE LUNGS, OR

SOMETHING GOT STUCK IN THERE,
AND YOU'RE GOING TO COUGH OR

CHOKE UNTIL YOU SPIT IT OUT.

JACK: HI, MY NAME IS JACK.

AND MY QUESTION IS HOW BIG IS
THE AVERAGE STOMACH?

DR. STORY: THE AVERAGE STOMACH
IS USUALLY ABOUT THE SIZE OF A

FIST.

WHEN WE LOOK AT THE AMOUNT THAT
IT CAN HOLD, IT CAN USUALLY HOLD

ABOUT ONE LITER OR ONE QUART,
AND THAT'S USUALLY ABOUT FOUR

CUPS OF WATER, FOUR CUPS OF
MILK.

THAT IS ROUGHLY ABOUT ONE QUART.

AND WHEN FULLY DISTENDED, THE
STOMACH CAN ACTUALLY HOLD ABOUT

ONE GALLON OF FLUID.

JONNY: MY NAME IS JONNY.

AND MY QUESTION IS WHAT DOES
FOOD LOOK LIKE WHEN IT GOES DOWN

YOUR THROAT?

DR. STORY: SO FOOD GOING DOWN
THE THROAT LOOKS PRETTY MUCH

EXACTLY LIKE THE FOOD THAT WE
CHEW.

SO IF YOU'VE EVER TRIED TO SHOW
A FRIEND WHAT YOUR FOOD LOOKS

LIKE AFTER YOU'VE BEEN CHEWING
IT FOR A WHILE, THAT'S BASICALLY

EXACTLY WHAT IT LOOKS LIKE AS
IT'S GOING DOWN INTO YOUR

ESOPHAGUS.

AND, EVENTUALLY, WHEN IT GETS
INTO YOUR STOMACH, WE HAVE SOME

VERY LOOSE, CHEWED-UP FOOD THAT
IS IN LOTS OF DIFFERENT COLORS,

AND REALLY DOESN'T LOOK LIKE THE
FOOD THAT WE STARTED WITH AT

ALL.

ADDY: HI, MY NAME IS ADDY.

AND MY QUESTION IS WHAT WOULD
HAPPEN IF SOMETHING BAD HAPPENED

TO THE DIGESTIVE TRACT?

DR. SERICATI: SO IF SOMETHING
BAD HAPPENED TO YOUR DIGESTIVE

SYSTEM, IT WOULD PROBABLY LET
YOU KNOW THERE'S SOMETHING

WRONG.

AND SINCE THERE'S A LOT OF
DIFFERENT KINDS OF BAD THINGS

THAT CAN HAPPEN TO YOUR
DIGESTIVE SYSTEM, THERE'S A LOT

OF DIFFERENT THINGS IT WILL TELL
YOU.

SOMETIMES IT WOULD TELL YOU THAT
I'M NOT FEELING WELL, AND YOU

WOULD THROW UP.

SOMETIMES IT WOULD SAY I'M NOT
FEELING WELL AT ALL, AND YOU

WOULD THROW UP BLOOD.

SOMETIMES YOU GET LOOSE STOOLS,
OTHERWISE KNOWN AS DIARRHEA.

SOMETIMES YOU CAN'T HAVE A POOP.

OTHER TIMES IT'S JUST THAT YOUR
BELLY HURTS.

AND THERE'S A LOT OF DIFFERENT
SIGNALS THAT YOUR DIGESTIVE

TRACT CAN TELL YOU WHEN IT IS
NOT HAPPY, AND YOU JUST HAVE TO

LISTEN TO IT.

HENRY: HI, MY NAME IS HENRY.

AND I WANT TO KNOW HOW YOU
HICCUP.

DR. STORY: HICCUPPING USUALLY
INVOLVES SPASMING OF THE

DIAPHRAGM.

AND THE DIAPHRAGM IS A LARGE
MUSCLE RIGHT BELOW OUR LUNGS

THAT HELPS TO US BREATHE.

SO WHEN WE TAKE A BIG, DEEP
BREATH IN, THE DIAPHRAGM

FLATTENS AND ALLOWS US TO
BREATHE.

BUT AT THE SAME TIME, THAT
DIAPHRAGM LIES RIGHT OVER THE

TOP OF THE STOMACH.

AND AT SOME TIMES WHEN THAT
DIAPHRAGM STARTS TO SPASM OR

CONTRACT, IT CAN ACTUALLY CAUSE
THE STOMACH TO PULL IN AIR, AND

THEN WE GET THIS HICCUP.

AND EVENTUALLY WE MAY NEED TO
BURP SOME OF THAT AIR BACK OUT.

MAX: MY NAME IS MAX.

AND MY QUESTION IS WHAT CAUSES
HEARTBURN?

DR. SERICATI: SO HEARTBURN
OCCURS WHEN THE STOMACACIDS

COME UP INTO THE SWALLOW TUBE,
CALLED THE ESOPHAGUS.

IT'S A VERY COMMON CONDITION
THAT WE SEE WITH BOTH YOUNG AND

OLDER PEOPLE.

AND THERE'S A LITTLE MUSCLE THAT
SITS AT THE BOTTOM OF YOUR

SWALLOW TUBE, OR THE ESOPHAGUS,
AND IT'S CALLED A SPHINCTER

MUSCLE.

A SPHINCTER MUSCLE IS DESIGNED
TO OPEN AND CLOSE WHEN YOU NEED

TO.

WHEN PEOPLE EAT, THAT SPHINCTER
MUSCLE OPENS AND LETS THE FOOD

DOWN, AND THEN IT'S SUPPOSED TO
STAY CLOSED.

AND WHEN YOUR STOMACH TURNS ON
ALL THE ACID PUMPS, IT'S

SUPPOSED TO KEEP THE ACID IN
YOUR STOMACH.

BUT SOMETIMES WHAT HAPPENS IS
THAT MUSCLE RELAXES TOO MUCH AND

ALLOWS ALL THOSE ACIDS IN YOUR
STOMACH THAT ARE HELPING DIGEST

YOUR FOOD FLY UP INTO YOUR
ESOPHAGUS, AND THAT CAUSES A

BURNING SENSATION THAT PEOPLE
CALL "HEARTBURN."

CARTAN-HANSEN: I'M SORRY, WE'VE
RUN OUT OF TIME.

MY THANKS TO DRS.

SERICATI AND STORY FOR ANSWERING
STUDENTS' QUESTIONS.

DR. SERICATI: THANKS AGAIN, WE
HAD A BLAST.

DR. STORY: WE HAD A GREAT TIME,
THANK YOU.

CARTAN-HANSEN: AND MY THANKS,
ALSO, TO THE FOLKS HERE AT IDAHO

GASTROENTEROLOGY FOR HOSTING US.

IF YOU WANT TO LEARN MORE, CHECK
OUT THE "DIGESTIVE SYSTEM" AREA

ON THE SCIENCE TREK WEBSITE.

YOU'LL FIND FACTS, LINKS, GAMES,
OUR DIGESTIVE SYSTEM BROADCAST

SHOW, AND LOTS MORE.

AND EVERY WEEK CHECK OUT MY BLOG
FOR THE LATEST SCIENCE NEWS FOR

KIDS.

ALL AT IDAHOPTV.ORG.

THANKS FOR JOINING US FOR
SCIENCE TREK: THE WEB SHOW.

(MUSIC)