The naso-oro-pharyngo-laryngeal airway.
Many of the muscles affecting the caliber of the upper airways have been shown to undergo a change in tone rhythmically timed to fit the breathing cycle. Failure in this function can adversely affect airway patency as in sleep-apnea. In normal persons the action of these muscles stabilizes the upper airways in a manner analagous to the action of the intercostals on the intrathoracic portion of the breathing apparatus. An important subject for future investigation is the exact nature of the nervous pathways involved.
D006801:Humans; D007830:Larynx / Q000502:physiology*; D009055:Mouth / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology; D009305:Nasopharynx / Q000502:physiology*; D012119:Respiration; D012137:Respiratory System / Q000503:physiopathology