Which structure is NOT part of the upper gastrointestinal tract?

• A. Oral cavity
• B. Pharynx
• C. Esophagus
• D. Large intestine

Answer: (D)

The upper part of the digestive tract includes structures involved in taking in and moving food from the mouth toward digestion—primarily the oral cavity, the pharynx, and the esophagus. Food enters through the mouth, passes through the pharynx, and is carried down the esophagus to the stomach. The large intestine sits further along in the digestive sequence, handling water absorption and stool formation after the small intestine, and is classified as part of the lower GI tract. So the large intestine is not part of the upper GI tract.