An endoscope is employed by a physician to view the internal parts of a body organ. It is based on the principle of

    

Endoscopy means looking inside and refers to looking inside the human body for medical reasons. In an endoscope thousands of optical fibers are bundled together which is inserted into human body. Light can be directed down the fibers even if they are bent, this illuminates the area under observation. The surgeon can view this from a television camera linked to a monitor by other fibre. Hence, it is based on the principle of total internal reflection.