Endoscope view of a healthy, normal stomach showing the antrum and pylorus. The pylorus is the lowest part of the stomach, containing the pyloric sphincter. This sphincter opens and closes to control the release of food to the duodenum of the small intestine. The pyloric antrum is the lower portion of the stomach just above this region. Endoscopy involves inserting a fibre optic tube down the throat into the stomach, where it can be used to check for cancer, ulcers or other disorders.