Anaesthetists expend a great deal of professional care on vocal cords. These delicate structures are positioned at the entry to the trachea and lungs; they vibrate to produce sound during speech and singing.
During spontaneous breathing the cords are open and they close during straining. For some operations, anaesthetists pass a tube through the vocal cords in order to control breathing.
This video shows the cords in action during singing…(produced and directed by Sara Lundberg)