An endoscope is a medical device utilized in many diagnostic procedures. It is a flexible tube that has a tiny, optically-sensitive computer chip at the end. As the doctor guides the endoscope through the upper gastrointestinal tract, it sends electronic signals to a computer that displays live images on a video screen for the doctor to see. Though an endoscope may sometimes only be used to get a closer look at the esophagus, stomach, and first portion of the small intestines, it can also help perform other functions. The open channel of the scope allows other medical instruments to be passed through it to obtain tissue samples, remove polyps, or perform other exams.