The pancreas is a gland in the abdomen that produces enzymes which aid in the digestion of food. (mscc.ca)
They then move on into the pet's upper intestine to aid in the digestion of fats. (2ndchance.info)
Each section of the gastrointestinal, or GI, tract plays a role in digestion of food and hence has distinct structural as well as molecular differences. (sciencedaily.com)