The Digestive System Lab

Digestive Organ Model

Digestive Organ	Material Used	Approximate Length (cm)
Mouth	red ribbon	12.2
Esophagus	gold ribbon	39.5
Stomach	purple ribbon	14.6
Small Intestine	white string	731.52
Large Intestine	blue ribbon	182.88
TOTALS	-	990.70 => 9.9070m

Questions
1. We took approximate measurements of our own digestive systems and used lengths of string or ribbons to create a crude model representing its length. It was interesting to see how much longer the small intestine was, even longer than all of the other sections put together. I would assume that that length makes the food take longer to pass through the small intestine, and thus allows more nutrients and material to be absorbed from the food.

2. height = 6' 0" = 72 in. = 1.8288 m.
ratio of height to length of digestive system- approximately 1 : 5.4
Since my digestive system is about five and a half times longer than my height, I can only assume it has been folded, squeezed, and stuffed to stay inside my belly.

3. I would think that food particles would take possibly a day or two- from 24 to 48 hours- from the moment they are swallowed to the time when they are finally excreted, varying based on posture and level of activity. However, I am surprised to learn that it actually takes, on average, "53 hours total transit time, from eating to elimination in stool" (Picco). I think that the horrendously long time that our digestive system takes to work is for completely sanitizing and breaking down swallowed food, absorbing as much of the nutrients as possible, and then packaging it (ewww) so that it can be removed efficiently.

4. Digestion is the breakdown of ingested foods and material into forms that the body is then able to manipulate and absorb nutrients from. Digestion involves the mouth (saliva), stomach (digestive enzymes), small intestine, and large intestine, while absorption occurs only in the small and large intestines.

5. How do stomach enzymes and acids break down the many different kinds of food we eat?
Are we born with DNA coding that is specific for each food / molecular substance?