Download panty hose digestion from Christine Grauer

Pantyhose Digestion and Absorption
Christine Grauer (adapted from another teacher’s demonstration)
Materials:
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Quart-sized Ziploc bag
Scissors
Knee High Pantyhose
Napkins (red if possible, one white) or Paper towels
Gloves (if students participate)
Food: oatmeal (good stuff), saltine crackers, banana, water, vegetable oil, etc.
Time needed:
10-20 minutes or more depending on how much discussion takes place
When can I use this?
- Before or after teaching digestion, absorption, and/or peristalsis
- To model organs and functions of the digestive system
Procedure/Series of Questions:
Before you begin, place red napkins in a large bowl (for easiest clean-up) or on the table. This
will represent the blood. On top of the red napkins, unfold and lay a white napkin. This
represents the single layer of cells in the small intestine that absorbs nutrients before they enter
the blood.
Where does digestion begin? the mouth
What does the mouth do? crush food and make it wet
Where does it go next? through the esophagus to the stomach
Start to put food in the Ziploc bag. Oatmeal for breakfast, crackers and soup for lunch, oil for fat,
banana for snack, etc. Add water or another liquid for drinks.
What happens to food in the stomach? It is digested (broken down).
How is it digested? Acids and muscles help to mix the food until it becomes chyme.
Seal the Ziploc bag and start to massage the contents of the bag. Add water to represent
hydrochloric acid, if you wish.
Do we have to think to make the muscles in our stomach move to mix food? No, so they are involuntary
muscles.
When food is digested, where does it go next? small intestine
Cut a small corner of the bag. Place the opening of the pantyhose at the corner of the bag and
squeeze the food contents into the pantyhose.
At this point, I explain more about final digestion and absorption as I do the demonstration:
All the cells in our body (eye, heart, muscle, brain, skin, kidney, stomach, etc.) need food.
Tiny cells need tiny pieces of food made of atoms: molecules too small to see with a microscope.
Enzymes released by the small intestine break down food into the smallest pieces that cells need. When
food is small enough, the molecules pass through the small intestine and go into the blood (absorption).
Once molecules enter the blood, they can be transported around to body cells.
Absorption means to soak up or take in.
Once the food is in the pantyhose, massage the food along the length of the panty hose. The liquid
that comes out will be absorbed by the white napkin followed by the red napkins.
The cells of the small intestine absorb nutrients just like the paper towels in the bowl soak up the tan
liquid that seeps through the pantyhose at this part.
The food will sit in the pantyhose until you move it down the hose. You can have students (with
gloves) demonstrate peristalsis by squeezing the food while holding the pantyhose horizontally.
Before or after, you can also demonstrate that the small intestine is long (stretch the hose) but it
fits inside the small space of your abdomen (fold the hose).
What is the last organ of the digestive system? the large intestine
What are the two functions of the large intestine? absorb water and eliminate solid waste
For this last step, push the food to the end of the hose.
Give the food a last good squeeze (a LOT of liquid will come out).
With a scissors, cut a small part of the end of the hose, and squeeze out the last of the foodstuff.
This should get the best reaction from students.
Even the water that the large intestine absorbs goes back into the blood.
Remind students that the absorbed water is not urine.
Afterward, you can discuss how fiber in our diet (oatmeal is a good source) is not digested, so it is not
absorbed, and it adds mass to solid waste. You can also discuss how diarrhea is a common symptom of
gastrointestinal illness, like some forms of food poisoning and lactose intolerance, and the cause of
diarrhea (water is not absorbed by the large intestine, which allows the body to “flush out” foreign
invaders).