Mechanism of swallowing

1. PHYSIOLOGY OF
SWALLOWING

3. PHYSIOLOGY OF SWALLOWING
.
• The swallowing centre in the
medulla integraes the functions
of cranial nerve V, VII, IX, X and
XII
PHASE OF SWALLOWING
• Oral phase
• Pharyngeal
• esophageal

4. STRUCTURES GUIDING FOOD DIRECTION
• Soft palate
• Posterior base of tongue
• Tonsilar pillars

5. oral phase (transport phase)

6. In Oral phase;
• Food is chewed lubricated and converted to bolus
• This is then propelled to pharynx
• Tonge is elevated against palate and food is propelled into oropharynx
• It is a voluntary phase

8. Pharyngeal phase

9. In Pharyngeal phase;
• Once food comes into oropharynx, reflex actions occur to stop food
from entering nasopharynx, oral cavity and larynx
• Thus food is carried past oropharynx and nasopharynx to the
oesophagus

10. Nasopharynx
• Closure of nasopharynx which occurs when soft palate contracts
against passavants ridge cuts & off nasopharynx from oropharynx

11. Oropharynx
• Closure of oropharyngeal isthmus which occurs which occurs due to
sphincter action of palatoglossal muscles when tongue contracts
against soft palate , prevents entry of food back to orocavity

15. Larynx
• Closure of laryngeal inlet by
contraction of aryepiglottic folds
and closure of false and true
cords prevent aspiration of food
into larynx
• There occurs temporary
cessation of respiration rising of
larynx under base of the tongue
• Epiglottis deflects backwards as
food passes into pyriformis fossa

17. Hypopharynx
• When pharyngeal muscle contracts, upper esophageal sphincter
(cricopharyngeus muscle) relaxes
• Food passes from pharynx to esophagus
• NB; cricopharyngeus muscle is at the junction btn pharynx and
esophag

19. Esophageal phase

20. In Esophageal phase ;
• Once food enters esophagus, crocopharyngeal sphincter closes .
• primary peristalsis of esophagus propels food down esophagus
• Secondary peristalsis propels food into stomach

23. REFERENCES
Diseases of ear, nose and throath by Mohan Bansal

24. THANK YOU

25. Good luck