What is MASTICATION?

1. What is MASTICATION?

2. Cutting of food substances into small particles and grinding them into a soft bolus is known as mastication

3. Significance of mastication: • Breakdown of foodstuffs into smaller particles • Mixing of saliva with food substances thoroughly • Lubrication and moistening of dry food by saliva • Appreciation of taste of the food

4. Muscles of mastication Center- Medulla and Cerebral cortex Mandibular division of v cranial nerve

6. What is DEGLUTITION ?

7. Deglutition is a process by which chewed food in emptied from the mouth into the stomach

8. Stages of deglutition • ORAL STAGE • PHARYNGEAL STAGE • ESOPHAGEAL STAGE

9. ORAL STAGE • Voluntary stage • Bolus passes through oral cavity into the pharynx

10. Movements of Oral stage • Once the bolus is formed it is projected on to the back of the tongue • The tongue is elevated and pressed against the hard palate . • Soft palate is elevated.

11. The bolus is propelled into pharynx • The forceful contraction of tongue against the palate produces a positive pressure in the posterior part of the oral cavity

14. PHARYNGEAL STAGE • involuntary stage • Bolus is pushed from pharynxinto esophagus

17. BACK INTO THE MOUTH • UPWARDS INTO NASOPHARYNX • FORWARDS INTO LARYNX • ENTRANCE OF BOLUS INTO ESOPHAGUS

18. BACK INTO THE MOUTH • The position of tongue against palate • High intraoral pressure developed by the movement of the tongue

19. UPWARDS INTO NASOPHARYNX • Upward movement of soft palate

20. FORWARDS INTO LARYNX • Approximation of the vocal cords • Forward and upward movement of larynx • Epiglottis swing backwards over the superior opening of the larynx • Temporary arrest of breathing

21. ENTRANCE OF BOLUS INTO ESOPHAGUS • Upward movement of larynx – stretches the opening of esophagus • Upper esophageal sphincter relaxes • Entire muscle of pharynx contracts

25. ESOPHAGEAL STAGE • involuntary stage • The function of the esophagus is to transport the bolus from the esophagus to the stomach

27. Primary peristaltic contractions • Secondary peristaltic contractions

28. Primary Oesophageal peristalsis- • It is the continuation of the peristaltic wave that is produced in the pharynx by the contraction of the superior pharyngeal constrictor • Its function is to propel the food through the esophagus to the stomach • The vagus controls the esophageal peristalsis through the myentric plexus

29. If the primary peristaltic wave fails to evacuate the food bolus, then the secondary peristaltic wave arises byVago- vagal reflux

30. Difference b/w 10 and 20 peristalsis Primary: • Initiated by swallowing and begins when the food passes into Oesophagus from Pharynx . • Coordinated by vagal fibers from the swallowing centre. Secondary: • Initiated by the presence of food in Oesophagus after the primary peristalsis is complete and is due to the mechanical or irritant receptor stimulation. • Coordinated by intrinsic nervous system of Oesophagus .

32. OESOPHAGEAL PERISTALSIS

34. 1. Pharyngo- eesophageal sphincter : - formed by the tonic contraction of the cricopharyngeus muscle - It is normally closed except during the deglutition - It prevents the entry of air from the mouth into the esophagus • 2. Gastro- esophageal sphincter

35. DEGLUTITIONREFLEX Sensory receptors-Tonsillar pillars, posterior pharyngeal wall, soft palate, epiglottis Afferent – V, IX, X cranial nerves Deglutition center-Located in the floor of the IV ventricle near the resipiratory center in the medulla Efferent - V, VII, IX, X, XII, cranial nerves Effectors – Pharyngeal musculature and tongue

36. APPLIED PHYSIOLOGY

37. BUCCAL STAGE • Painful inflammatory process involving the mouth and the tongue • Paralysis of the tongue • Congenital anomaly of lips, tongue and palate

38. Pharyngeal stage • Acute pharyngitis • Tonsilitis • Carcinoma of the larynx or thyroid

39. Oesophageal stage • Diffuse spasm of the esophagus • Carcinoma of the esophagus • Achalasia cardia • GERD- Heart burn

43. . Thank you for your attention