Deglutition (Swallowing)

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  • Created by: SamDavies
  • Created on: 24-04-18 00:19

Buccal/Oral Phase

  • Voluntary
  • The tongue can force the bolus of the food towards the pharynx
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Pharyngeal Phase

  • Involuntary
  • The soft palate and uvula of the mouth can fold upward to cover the nasopharynx which prevents the passage of food into the nasal cavity
  • The epiglottis (flexible flap of cartilage) covers the opening of the larynx/trachea so food only passes into the oesophagus

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Oesophageal Phase

  • Involuntary
  • Oesphagus
    • Upper 1/3 = skeletal muscle
    • Middle 1/3 = skeletal and smooth muscle
    • Lower 1/3 = smooth muscle
  • The upper oesophageal sphincter opens to allow food to pass when the larynx rises during swallowing
  • Peristaltic action pushes the food down and it is controlled by the "swallowing centre" in the brain
  • When the food reaches the lower end of the oesophagus, the lower oesophageal sphincter opens to allow the food to enter the stomach
  • The LOS closes immediately afterwards to prevent reflux of acid from going up the oesophagus
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