Download The Digestive System

The Digestive
System
What’s really happening to
the food that we eat?
Think about this…
Just like a car needs fuel to go…
…Our bodies need food
to keep working.
However, We’ve got a problem…
Most food that you
eat is too big and
complex for your
tiny cells. That’s
when the Digestive
System comes into
play.
What is Digestion?
Digestion-breaks
down food into
smaller and simpler
substances that your
body can absorb.
WHISPER TO YOUR NEIGHBOR
What
does
Digestion
do?
It breaks down food into smaller and simpler
substances that your body can absorb.
Let’s take a journey through our
body to see where our food travels…
st
1
Stop…The
MOUTH!
What goes on in the mouth?
When you first eat your
food, it goes straight
into your mouth! The
mouth and teeth are the
first steps in breaking
food down. The mouth
supplies chewing and our
tongue is used for
tasting.
Let’s pretend you are going to
take a great big bite of an apple.
Once you take that bite…your teeth start tearing
through the apple skin and grind the apple into a
ball of food (also known as bolus).
When the apple touches your tongue, your taste
buds tell you it is sweet.
The salivary glands in your mouth and throat
produce a watery fluid called saliva. Saliva helps
to moisten and soften the bolus and break it
down chemically.
Now that our food is all chewed up…
Our tongue moves the chewed up
apple to the back of our mouth
and we…
SWALLOW IT!
MouthThe teeth grind up the food.
Salivary glands in your mouth
produce saliva which softens
the bolus (ball of food) and
breaks it down chemically.
nd
2
Stop…The Esophagus
What does the esophagus do?
When you swallow
your food, it goes
down your
esophagus. Your
esophagus is a tube
that is about 10
inches long that
connects your
mouth to your
stomach.
Esophagusa tube that connects
the mouth to the
stomach.
“Wait… what are the first
two organs in the
digestive system? Point
to them and tell me
them.”
The
MOUTH
and
the ESOPHAGUS!
Nice Job!
What comes
next?
rd
later…3
10 seconds
Stop…
the STOMACH!
The Stomach…
When food enters the
stomach, the muscles in
the stomach contract
and relax to create
movement.
Then in the stomach
acids and digestive
juices transform the
food into a liquid
substance.
Think about it this way…
Think about mixing the
ingredients to make a
cake.
You take a spoon and start
stirring the ingredients
creating a movement
that resembles the
contraction. It isn’t
until you add a liquid
substance (egg/oil) that
the ingredients begin
transforming into a
liquid substance.
StomachThe walls of the stomach have
glands which produce acids and
mucus. The muscles of the
stomach contract and create a
movement. The muscles
squeeze and mix the bolus until it
is changed into a thick liquid.
After about 4-6 hours later
of mixing and squeezing,
the liquid is released into
the….
th
4
Stop…Small Intestine
The Small Intestine
Okay…Now our bolus has transformed into a
liquid substance. Here in the small intestine,
chemicals from the pancreas and the liver
continue to mix with the bolus. The digestive
juices break down the nutrients from the food
into smaller, simpler forms. The nutrients are
absorbed by the small intestine. The nutrients
pass through the walls of the small intestine
into tiny blood vessels that are transported
throughout the body.
food passes into the bloodstream through
the villi, which line the small intestine walls,
and are transported throughout the body.
Small IntestineA coiled, tubular organ that
breaks down the food mixture so
your body can absorb all the
nutrients through tiny hairs called
villi.
WHISPER TO YOUR NEIGHBOR
What
are the
first 4 organs
in the
digestive
system?
The mouth, esophagus, stomach, and small intestine.
But wait…what happens to the food
that I couldn’t digest?
th
5
Stop…
The LARGE INTESTINE!
Large Intestine Cont.
The parts of the apple
that you could not
digest move into the
large intestine. The
large intestine is a
thick, tubular organ
that removes
undigested waste.
Large IntestineA thick tubular organ that
removes undigested
waste.
6th Stop…
The Rectum
Solid waste called
feces is
eliminated from the
body
through the rectum.
RectumSmall waste called feces
is eliminated from the
body.
“Wait… what is the order
the organs in the
digestive system?”
 The
mouth, esophagus, stomach,
small intestine, large intestine,
rectum.
 Think: MESSLR
Now that we know how
the Digestive System
works…
Let’s put it into action.