Hering-Breuer reflexes are mediated by

Hering-Breuer reflexes are mediated by slow adapting pulmonary stretch receptors and the impulses travel in the vagus nerve large myelinated fibers. Hering-Breuer Inflation Reflex: " Prolonged inspiration inhibits fuher inspiration" Hyperinflation of lungs stimulates slowly adapting pulmonary stretch receptors and the impulses travel in the vagus nerve large myelinated fibers. This signal inhibits the inspiratory ramp signals of the dorsal repsiratory group of neurons (DRG), thus, inspiration is quickly inhibited and expiration follows. Advantages of Hering-Breuer inflation reflex: It cuts down the inspiration time, and therfore., IT prevents overinflation of the lungs. Lungs operate at lower lung volumes increases to more than three times the normal tidal volume (tidal volume = 0.5 liters/breath; so , lung volume > 1.5 liters per breath activates the reflex). It signifies that the reflex play a protective role preventing the overinflation of the lung rather than regulating the normal venilation. Ref: Guyton and Hall 13th edition Pgno: 540