Upper gastrointestinal tract

The upper gastrointestinal (GI) tract includes the body's first part of the digestive system, starting from the mouth and ending at the small intestine's beginning. It consists of the mouth, esophagus, stomach, and the initial section of the small intestine called the duodenum. This pathway is responsible for the intake, initial breakdown, and passage of food, as well as the release of digestive acids and enzymes that help break down food for nutrient absorption. It also acts as a barrier against harmful substances and plays a role in signaling hunger and fullness.