The digestive system of the upper abdomen and the chest is also known as the upper gastrointestinal (GI) tract. It includes several of the digestive system’s most important organs, including the esophagus, stomach, duodenum, liver, and gallbladder. These organs are responsible for significant breakdown of food and for transporting the partially digested food further along the alimentary canal.
Food entering the long, tube-like esophagus from the throat is moved by peristalsis toward the stomach. Upon reaching the stomach, food is stored and digested by being mixed with acid and digestive enzymes to form a liquid called chyme. Next, this chyme passes slowly into the duodenum, the first segment of the small intestine. Bile from the liver and gallbladder along with enzymes from the pancreas are added to chyme in the duodenum to further digest it into small nutrients that can be absorbed by the intestines.