Digestive System Demonstration

Mouth Put graham crackers and banana in a gallon Ziploc bag and crunch up.

Salivary Glands Add a small amount of water to make the mixture moist.

Tongue Press the mixture into a “bolus” (ball).

Esophagus Moves the “bolus” to the stomach through “peristalsis” (muscular contractions of the esophagus)

Stomach Continues to mix and churn the “chime” in the Ziploc Bag

Pancreas Add a little sodium bicarbonate (baking soda) to dissipate gas caused by the chemical reactions in the stomach.

Liver Produces bile to aid in the break down of the food in the stomach (Pass salt to the gall bladder)

Gall Bladder Add a little salt (bile) to further break down the food into proteins and enzymes

Small Intestines (Now things start to get interesting!) Cut a corner from the Ziploc bag and squeeze the contents into a stocking. The person holding the stocking moves the food from the top and distributes it evenly into the stocking. (The “villi” are absorbing the nutrients from the food.)

Large Intestine This person will start squeezing out the moisture from the food, which is exactly what happens in the large intestine. (Hold the stocking over a bucket to do this step.)

Rectum Now the “feces” are collected at the end of the stocking. Cut a hole in the end of the stocking (relaxing the “anus”)

Toilet The rectum squeezes the “feces” into the toilet!