Chapter 32 - Physiology of Aerodigestive Reflexes in Neonates and Adults

Abstract

The physiological functions of the aerodigestive tract and the intricate relationships between the brain, airway, and foregut are essential to maintain feeding and breathing, and therefore have an impact on the quality of life. In this chapter, we review the development and maintenance of these functions across the age spectrum. Specifically, neuromotor reflexes that facilitate swallowing, airway protection, and aspiration-preventing mechanisms are highlighted. Pulmonary aspiration can occur in two scenarios: (1) anterograde aspiration during swallowing and (2) retrograde aspiration during gastroesophageal reflux events. There are a number of stimulatory reflexes involving the pharynx, esophagus, and larynx that prevent pulmonary aspiration: deglutition response, secondary peristalsis, upper esophageal sphincter contractile and relaxation reflexes, laryngeal adductor reflex, esophagoglottal closure reflex, and pharyngoglottal closure reflex. Maldevelopment, malfunction and maladaptation of these functions pose continued threats with the consequence of dysphagia, chronic airway problems, speech problems, gastroesophageal reflux disease, and impaired quality of life.