SWALLOWING corrected slides pptx and PDF

Mechanism of swallowing

1. PHYSIOLOGY OF SWALLOWING

2. 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

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

4. oral phase (transport phase)

5. 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

6. Pharyngeal phase

7. 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

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

9. 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

10. 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 ris ing of larynx under base of the tongue Epiglottis deflects backwards as food passes into pyriformis fossa

11. 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

12. Esophageal phase

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

14. REFERENCES Diseases of ear, nose and throath by M ohan B ansal

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