Deglutition is defined as the act of swallowing in which liquids, solids, or both are transported from the mouth to the stomach, by way of the pharynx and esophagus.
Swallowing occurs up to 600 times a day and swallowing takes approximately 15 seconds to complete.
Swallowing utilizes more than 30 muscles.
Deglutition is divided into 4phases – 1, preparatory, 2 oral, 3 pharyngeal, and 4 esophageal.
Deglutition begins as food enters the mouth with muscles of mastication and the tongue mixing saliva with food, to generate a bolus of appropriate shape, size and consistency.
The anterior part of the tongue contacts the hard palate by elevation and moves posteriorly to force the food bolus into the upper pharynx.
The above process elevates the soft palate and seals off the nasopharynx to prevent nasal regurgitation, and directs the food bolus posteriorly.
The suprahyoid muscles contract and move the larynx anteriorly and superiorly.
The epiglottis moves inferiorly to cover the trachea
Subsequently the pharyngeal muscles contract and push the food bolus past the upper esophageal sphincter or cricopharyngeus muscle, which relaxes shortly after laryngeal elevation, allowing the bolus to move it to the proximal esophagus.
The food bolus is propelled by peristalsis through the esophagus and across the lower esophageal sphincter.