The endoscope is a convenient optical instrument which can be used to examine inside human and animal bodies. In the early 20th century, shortly after the invention of electric light, an endoscope similar in principle to the one used nowadays was employed in explorations of the abdomen and the thorax. Today, the endoscope is usually the size of a pill and carries an adjustable video camera. These endoscopes can be powered by wireless transmissions and used in telesurgery. A typical endoscope has three components: an optical system, a cable, and a lumen. The light source is commonly outside the body and is transmitted inside through a rigid or flexible fiber optic cable. The image is transmitted through a capsule camera and projected on a video screen. In diagnostic and operative endoscope, an additional channel may be employed to allow for the entry of instruments required to perform a biopsy or operate. Endoscope technology is commonly used in human and veterinary medicine to get a deep look into the gastrointestinal tract. To perform this function, the esophagus, stomach, and duodenum--as well as the colon and rectum--can be viewed with an endoscope. The respiratory, urinary, and female reproductive systems can also be observed using endoscopy. This versatile device also finds a use in monitoring the amnion and the fetus during pregnancy. In order to enter the body or different organs, the endoscope can use an existing cavity or a small incision. The latter is the case in abdominal or pelvic laparoscopy and in arthroscopy, in which joint passageways can be examined. Endoscopes can also be of assistance in the insertion of breast implants. | 
