Each part of the digestive system plays a role in moving the food or liquid through the gastrointestinal tract. To break down food into smaller size, our pancreases will secrete digestive enzymes into our small intestine. The small intestines will then mix the enzymes with the food via a movement called peristalsis. This will help to break down carbohydrates, proteins and fats into smaller molecules for our body to absorb the nutrients. Small intestines are also responsible for the absorption of nutrients. Once this is done, the food residue will move on to the large intestines to further absorb water and to be removed from our body.