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From the time of birth, acquisition of nutrients essential for growth and development of the infant is determined by a complex interplay of hunger, feeding and swallowing skills, and the social environment meeting those nutrient needs. Appropriate interplay results in a mutually satisfying feeding and mealtime experience for both infant and caregiver, reinforcing bonding. A deficit in any of these areas is termed feeding difficulties, or feeding disorder.
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Functionally feeding and swallowing are complex processes divided into 4 phases, as shown in Figures 23-1 and 23-2. The first phase is the preoral phase, which is dependent upon the infant/child’s sensation and communication of hunger. The second phase, the oral phase, is the oral cavity–food processing phase where food or liquid is formed into a bolus, enabling safe passage through the pharynx. The next steps in the swallow process are reflexive, and therefore, involuntary. In the ensuing pharyngeal phase, the bolus contacts the tonsillar pillars and pharyngeal wall, resulting in elevation of the larynx, closure of the vocal cords, and relaxation of the esophageal sphincter. Then, contraction of the pharynx deposits the food bolus in the esophagus. During the passage of the food bolus through the pharynx, coordination between breathing and swallowing is essential to prevent aspiration. The final phase, the esophageal phase, moves the food bolus into the stomach and then small intestine, where the processes of digestion and nutrient absorption occur. Any developmental change in the phases of swallowing occurring from infancy through adulthood will impact the ability to feed successfully.
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