Vocal cords. Bronchoscope image showing the human vocal cords during speech, appearing parallel and in close proximity to each other. The relative movement of the vocal cords interferes with the airflow in the larynx (top part of windpipe), thus producing the audible vibrations that constitute speech, song and other vocal noise. In the upper frame is the epiglottis, a leaf-shaped flap which covers the entrance to the larynx when food is being swallowed. The bronchoscope is a type of endoscope, a flexible cable carrying a light source which allows observation of otherwise inaccessible areas of the body.