Illustration of a labelled endoscopic examination: In a gastroscopy, mucosa of the esophagus, stomach (gaster) and parts of the small intestine are evaluated with a camera and tissue samples (biopsy) are taken. The camera tube (endoscope) is pushed forward through the mouth into the esophagus up to the stomach and adjacent parts of the small intestine. It serves to judge tissue changes such as tumors or varices (esophageal varices).