• Deglutition (swallowing) is the transfer of a bolus of food from the mouth down the pharynx and esophagus to the stomach.
• Encompasses the oral, pharyngeal, and esophageal phases

  • Oral Phase (Deglutition)

    • Voluntary process.
    • The bolus of food is masticated (chewed), moistened in saliva, and propelled towards the oropharynx by the tongue (primarily via the palatoglossus and styloglossus muscles).

  • Pharyngeal Phase (Deglutition)

    • Involuntary process.
    • Once the bolus of food is propelled backward, the levator veli palatini and tensor veli palatini muscles elevate the soft palate, preventing food from entering the nasopharynx.
    • The walls of the pharynx are elevated by the contraction of longitudinal pharyngeal muscles:
      • Salpingopharyngeus
      • Palatopharyngeus
      • Stylopharyngeus
    • The suprahyoid muscle contracts, elevating the hyoid bone and the larynx.
    • The epiglottis closes.
      • Protect the opening of the larynx
      • Prevents the passage of food into the trachea and respiratory tract(prevent aspiration).
    • Can be affected by a stroke of the brainstem.

  • Esophageal Phase (Deglutition)

    • Involuntary process.
    • Contraction of the pharyngeal constrictor muscles (superior, middle, and inferior) propels the bolus of food downward to the esophagus.
    • Esophageal peristalsis propels food towards the stomach.
    • Affected by achalasia.

Airway-protective movements

• Displacement of the larynx superiorly and anteriorly under the base of tongue, which allows food to be directed into the more posteriorly located esophagus
• Tilting of the epiglottis to block the airway
• Closing of the glottis by adduction of the vocal folds