Anatomy & Physiology I and II

Anatomy & Physiology Study Guide

Swallowing Swallowing, or deglutition, is a complex process that can be initiated voluntarily but proceeds automatically once it begins. Although you take conscious control over swallowing when you eat or drink, swallowing is also controlled at the subconscious level. For example, swallowing occurs at regular intervals as saliva collects at the back of the mouth. Each day you swallow approximately 2400 times. Swallowing can be divided into buccal, pharyngeal, and esophageal phases: •

The buccal phase begins with the compression of the bolus against the hard palate. Subsequent retraction of the tongue then forces the bolus into the oropharynx and assists in the elevation of the soft palate, thereby sealing off the nasopharynx. The buccal phase is strictly voluntary.

©2018 Achieve Test Prep Page 318 of 367 The pharyngeal phase begins as the bolus comes into contact with the palatoglossal and palatopharyngeal arches and the posterior pharyngeal wall. The swallowing reflex starts when the passage of the bolus is stimulated by tactile receptors on the palatal arches and uvula. Then the information is relayed to the swallowing center of the medulla oblongata over the trigeminal and glossopharyngeal nerves. It takes less than a second for the pharyngeal muscles to propel the bolus into the esophagus. During this period, the respiratory centers are inhibited, and breathing stops. •