Final answer:
During swallowing, the soft palate and uvula rise to close off the nasopharynx, preventing the aspiration of food into the trachea. The food then moves through the oropharynx and laryngopharynx and enters the esophagus through relaxation of the upper esophageal sphincter.
Step-by-step explanation:
During swallowing, the soft palate and uvula rise reflexively to close off the entrance to the nasopharynx. At the same time, the larynx is pulled superiorly and the cartilaginous epiglottis, its most superior structure, folds inferiorly, covering the glottis. This process effectively blocks access to the trachea and bronchi, preventing the aspiration of food. The food then moves through the oropharynx and laryngopharynx and enters the esophagus through relaxation of the upper esophageal sphincter.