Bronchoscope image of the interior of a normal human trachea (windpipe), the airway connecting the throat and lungs; the trachea divides into the left and right bronchi which serve each lung. The bronchoscope is a type of endoscope. Images of inaccessible areas of the body are relayed from a lens & light source at the instrument's tip by flexible optical fibres; remote-controlled instruments allow for surgery & biopsy samples to be removed. Here, the rings of cartilage that prevent the trachea from collapsing are clearly visible, supporting a ciliated mucous membrane. The beat of the hair-like cilia sweeps the windpipe of particles of dirt.