SLHS 408 Physiology of Normal Swallowing

reflective, protective, complex, and a series of sensorimotor events

swallowing is

both: there is a relationship between voluntary and involuntary control of the swallow trigger

is swallowing voluntary or involuntary

1. oral prep

2. oral transport

3. pharyngeal

4. esophageal

what are the four stages of the swallow

begins when food is introduced into the oral cavity

it is chewed and mixed with saliva to form a bolus

what occurs during the oral prep phase

the bolus is propelled posteriorly by the tongue

tongue maintains its seal against the hard palate

a central groove is formed in the tongue

this stage ends with the initiation of the pharyngeal phase

what occurs during the oral transport phase

swallow reflect is initiated (under involuntary control)

triggered when the bolus head passes any point between the faucial arches and where the tongue base crosses the lower rim of the mandible

velum elevates and retracts to close off the nasal cavity

elevation and anterior movement of the hyoid and larynx

closure of the larynx (from bottom to top, first the true folds then false folds then epiglottis)

upper esophageal sphincter relaxes

tongue base contacts posterior pharyngeal wall

pharyngeal constrictor muscles squeeze the bolus from top to bottom

propels the bolus through to the esophagus

what occurs during the pharyngeal phase

begins when bolus enters esophagus at the upper esophageal sphincter

the peristaltic wave pushes the bolus through the esophagus

ends when bolus passes into the stomach at the lower esophageal sphincter

what occurs during the esophageal phase

lips, teeth, tongue, cheeks, mandible, hard palate, soft palate, faucial arches

what structures are important for the oral phases

tongue base, hyoid bone, valleculae, epiglottis, pyriform sinuses, aryepiglottic folds

what structures are important for the pharyngeal phase

upper esophageal sphincter

esophagus

• upper 1/3 is striated (voluntary) muscle fibers

• middle 1/3 is combination of striated (voluntary) & smooth (involuntary) muscle fibers

• lower 1/3 is smooth (involuntary) muscle fibers

lower esophageal sphincter (LES)

what structures are important for the esophageal phase

voluntary

is the oral prep phase voluntary or involuntary

CN V Trigeminal for chewing

CN VII Facial for

• sensory: bring information to the brain about material

• motor: maintaining labial seal & sucking

CN IX Glossopharyngeal for

• sensory: bring information to the brain about material

• tongue positioning and maintaining bolus

CN XII Hypoglossal for tongue positioning and maintaining bolus

what cranial nerves control the oral phase

food is chewed into smaller pieces

mixed with saliva, tongue forms a cohesive bolus

lips are closed and front of tongue is sealed against the alveolar ridge to prevent anterior loss

cheeks maintain tone and sides of tongue are sealed against hard palate/upper teeth to prevent lateral loss

soft palate is NOT pulled down (posterior loss common & normal)

what happens during the oral prep phase for food

liquid is contained as a cohesive bolus by how the tongue cups it

lips are closed and front of tongue is sealed against the alveolar ridge to prevent anterior loss

sides of tongue are sealed against hard palate/upper teeth to prevent lateral loss

soft palate IS pulled down to prevent posterior loss

what happens during the oral prep phase for liquid

during the oral preparatory phase for liquids

when is the soft palate pulled down to prevent posterior loss

involuntary

is the pharyngeal phase voluntary or involuntary

CN IX Glossopharyngeal for

• sensory: transmitting information about the bolus to the brainstem

• motor: elevating the larynx and pharynx

CN X Vagus

• sensory (pharyngeal branch): transmitting information about the bolus to the brainstem

• motor: for lifting the soft palate, squeezing the pharynx, closing the larynx

what cranial nerves control the pharyngeal phase

involuntary

is the esophageal phase voluntary or involuntary

elevates; retracts; nasal

during the pharyngeal phase, the velum _____ and _____ to close off the _____ cavity

elevate; anteriorly

during the pharyngeal phase, the hyoid and the larynx _____ and move _____

closes; bottom; top

during the pharyngeal phase, the larynx _____ from _____ to _____

true folds then false folds then epiglottis (bottom to top)

what is the order of closure of the larynx during the pharyngeal phase