Deglutition

Voluntary Phase

• Food (bolus) voluntarily squeezed to the back of oral cavity into oropharynx by movement of tongue upward and backward against palate

Pharyngeal Phase

• Bolus stimulate the receptor in oropharynx
• Impulses send to deglutition center in medulla oblongata.
• This causing the uvula and soft palate to move upward & close the nasopharynx which prevent swallowed foods and liquids entering the nasal cavity
• Epiglottis closes off the opening to larynx which prevent the bolus from entering the respiratory tract
• Once upper esophageal sphincter relaxed, bolus moved into esophagus

Esophageal Phase

• It begins once bolus enter the esophagus
• Peristalsis action pushes the bolus onward
• Circular muscles on the superior of the bolus contract and squeeze the bolus toward stomach
• Longitudinal muscles on the inferior to bolus contract and pushes the wall outward so it can receive the bolus
• As the bolus approaches the end of esophagus, Lowe Esophageal Sphincter (LES) relaxes and bolus moves into stomach