Pulmonary reflexes and control of breathing during development.

The potency of the Hering-Breuer inspiratory-inhibitory and expiratory-promoting reflexes decreases with maturation in mammals. The Hering-Breuer deflation reflex is present at birth and its power changes little during postnatal development. Already during the second day of life the airway defence reflex resembles that of the adult rabbits. In contrast, sensitivity of the pulmonary chemoreflex does not reach the adult level by the end of the first week of life in newborns of the same species. The time course of functional development of respiratory reflexes coincides with the maturity of different species at birth.