An endoscope in one configuration includes an elongated cylindrical core with a transparent window at the distal end thereof. A removable housing is placed within the core along with an objective endoscope lens or optics at the distal end thereof. A photosensitive image sensor is mounted within the core. A transmitting electronic means with multiple conductors each has a distal end connected to the image sensor circuit board or image sensor and a proximal end connected to a video control unit. From the video control unit signals are transmitted to the video monitor which displays the image. A separable and disposable sheath or channel section is provided in a sterile condition and removably receives the core in a defined relationship. The sheath has at least one longitudinal channel formed around its periphery for transmitting fluids or for receiving an operative instrument or carrying light transmitting fibers. A flexible tube is connected to the proximal end of the sheath for supplying fluid or for manipulating the operative instrument from a remote location. The sheath is disposable after use on a patient and the core is prepared for reuse with another sheath on the next patient. In a second configuration, an ultrasound transducer is placed through the core after a first visual image of the desired area has been taken by the image sensor. The core is open at the distal end to permit the transducer to extend beyond it during use.