The document discusses the human digestive system. It breaks down as follows: 1. The breakdown of some food starts in your mouth, where saliva begins to break it down. 2. As the food moves through the esophagus to the stomach, muscles and digestive juices further break it down. 3. In the small intestine, muscles continue mixing the food with digestive juices to fully break it down so nutrients can be absorbed into the bloodstream.