The Hering-Breuer inflation reflex prevents over-inflation of the lungs. The receptors and pathway mediating this reflex are:

• A Slowly adapting pulmonary stretch receptors in airway smooth muscle → vagal afferents → inhibition of inspiratory neurons in the medulla ✓
• B J receptors in alveolar walls → vagal afferents → inhibition of apneustic center in the pons
• C Rapidly adapting irritant receptors → vagal afferents → stimulation of expiratory neurons
• D Carotid body chemoreceptors → glossopharyngeal afferents → apneustic center inhibition

Explanation

The Hering-Breuer inflation reflex is mediated by slowly adapting pulmonary stretch receptors (SARs) located in airway smooth muscle, primarily in the trachea and large bronchi. As lung volume increases, these receptors discharge, sending signals via large myelinated vagal afferents to inhibit inspiratory neurons in the dorsal respiratory group (nucleus tractus solitarius), terminating inspiration. This reflex is active during normal tidal breathing in neonates and prominent during large tidal volumes; it helps set tidal volume and respiratory rate by establishing the inspiratory time.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

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Written and medically reviewed by the StethoPrep medical team.