The digestive system is a series of organs whose function is to break down food chemicals into energy supplies that travel in the blood stream to individual cells for nourishment. While it is primarily a chemical process (digestive juices, enzymes, etc. acting on the food source in the stomach and intestines), there is also a mechanical element—grinding, squeezing, etc. The process actually starts in the mouth, where starch begin breaking down, then through the esophagus, then to the main digestive organs, the stomach and intestines. (There are names for many of the passages and organs throughout the passage.) The chemical nourishment is separated from the bulk mainly in the small intestine, which then passes the bulk to the large intestine, for elimination. The small intestine’s main job is the transfer of energy from the digestive to the circulatory system. Many organs of the body contribute to the digestive process—spleen, thyroid, etc.--directly or indirectly.