Gastric antrum. Capsule endoscope view of healthy mucosa (wall) in the gastric antrum region of the stomach, with the pylorus region that opens to the duodenum visible. The stomach stores food and begins the process of digestion. A capsule endoscope is a tiny camera sealed in a pill-shaped container which can be swallowed. It provides real-time video images of the stomach and intestines as it passes through the digestive tract.