postinspiratory

Postinspiratory is a term used in respiratory physiology to describe events that occur after the end of inspiration within the breathing cycle. It denotes the portion of the cycle that follows the inspiratory phase and precedes full expiration, and is contrasted with inspiratory and expiratory phases.

Physiology: In quiet breathing, inspiration is active and expiration largely passive; the transition to expiration is followed by a brief postinspiratory interval during which inspiratory drive declines and lung recoil initiates exhalation. In some breathing patterns, such as during speech or sighs, or under certain conditions, there can be a more pronounced postinspiratory pause or variant timing, and expiration may be more actively controlled.

Neural and reflex control: The postinspiratory transition is regulated by brainstem respiratory centers, lung stretch receptors, and chemical feedback. Hering-Breuer reflexes help terminate inspiration when the lungs are stretched; vagal afferents and central pattern generators coordinate the switch to expiration. Postinspiratory activity has been described in physiological studies as part of the phase transition of the respiratory rhythm.

Clinical and research relevance: Analysis of postinspiratory timing and duration can be used in studies of respiratory mechanics, sleep physiology, and disease; measurements may employ spirometry, body plethysmography, or electromyography of respiratory muscles. The term is also used in neurophysiological contexts to describe neuronal activity following inspiration.