The effect of the larynx on the breathing pattern in anaesthetized rabbits

The effect of the larynx on the inspiratory and expiratory times was studied in anaesthetized rabbits. A model of "isolated larynx" used allowed for connecting it to or excluding it from the respiratory system. The inspiratory time (TI) inthe intact animals and those with the superior laryngeal nerves cut was significantly prolonged whether the larynx was switched in the inspiratory or expiratory phase, while in vagotomized animals the change was non-significant. The expiratory time (TE) was shortened in the intact and vagotomized rabbits but prolonged after section of the superior laryngeal nerves. Sensory denervated larynx then subserves only its valvular mechanisms, prolonging TE. Blow of fresh air on the vocal cords shortened TE as well, suggesting that the exhaled air may be the stimulus for this reflex.