The Upper GI Tract refers to the initial part of the digestive system, which includes the mouth, esophagus, stomach, and the first part of the small intestine called the duodenum. This section is responsible for the intake, breakdown, and initial digestion of food. In the mouth, food is mechanically broken down by chewing and mixed with saliva, which contains enzymes. The esophagus then transports the food to the stomach, where it is mixed with gastric juices for further digestion. Finally, the partially digested food moves into the duodenum for nutrient absorption.