SWALLOWING
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also known as deglutition
it is present since early in life
– fetus begin to swallow 10 to 11 weeks after conception
adults swallow 600 to 9000 times per day
frequency of swallow
– is least during sleep = 2 to 9 swallows per hour
– is highest during eating = about 300 per hour
STRUCTURES INVOLVED IN SWALLOWING
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lips
tongue
velopharynx
jaw
oropharynx
laryngopharynx
larynx
hyoid bone
upper esophageal sphincter
esophagus
upper esophageal sphincter
stomach
TERMINOLOGY
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mastication
deglutition
swallowing
chewing
bolus
peristaltic waves
PROCESS OF SWALLOWING
the passage ahead of the bolus is opened
the passage behind the bolus is constricted
food move along
– mouth
– pharynx
– esophagus
– stomach
– intestine
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velopharyngeal sphincter separates the nasopharynx from oropharynx
preventing food from going into nose
the epiglottis, aryepiglottic folds, false folds and true folds all work to prevent
food from entering the larynx and getting into lungs
PHASES OF SWALLOWING
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oral phase
– collects and prepare the bolus within the oral cavity and pushes it backward
to the pharynx by a sequential arching of the tongue against the palate
– under voluntary control
pharyngeal phase
– is marked by the arrival of the bolus to the faucial pillars
– neural control shifts from voluntary to reflexive
– respiration is interrupted
– this phase starts when the tongue flexes back on the hyoid bone to thrust
the bolus into the pharynx
– larynx and pharynx elevate
• larynx moves upward and forward under the root of the tongue
• the action of elevating the larynx and retracting the tongue results in the
epiglottis tipping downward to cover the laryngeal aperture
– when the larynx move upward and forward it triggers the cricopharyngeous
muscle to relax opening the upper esophageal sphincter
– aryepiglottic folds, false folds and true folds are all constricted to close the
airway preventing food from entering the airway
– the pharyngeal tube elevates as if to engulf the bolus
– peristaltic wave travels along it to carry the bolus to the esophagus
– the pharyngeal phase ends with the reopening of the laryngeal airway and
the resumption of respiration
esophageal phase
– starts when the food enters the esophagus
– peristaltic contractions progress along the length of the esophagus moving
the food
– during this phase food is carried from the UES to the LES and then enters
the stomach
• 3 seconds for liquids
• 11 seconds for solids
DISORDER OF SWALLOWING
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dysphagia
– can involve any or all of the phases of swallowing
– complications
• laryngeal penetration: when bolus enters the laryngeal aditus or vestible
• aspiration: when bolus moves passed the vocal folds
• reduced intake
– food
– liquids