Digestive system lab

In class we cut pieces of ribbon to represent the lengths of different parts in the  digestive system. I am roughly 5' 8" which is 1.72 meters. That means that my digestive system, which is 9.37 meters, is 5.5 times longer than my height. My body can hold all 9.37meters of my digestive system because it coils up and and utilizes space efficiently. The organs such as the stomach, large intestines, and small intestines, can all stretch and expand when needed. As a guess I'd say that food takes 4 hours to move through the entire digestive system, but I found out that it takes roughly 6-8 hours. Factors that can affect the the time taken include gender and age. Digestion differs from absorption because digestion breaks down the bolus while absorption takes in the minerals and vitamins. About the digestive system I'd like to learn how it knows what our body needs and how our body responds when there is a failure in the system.