Mastication Physiology slideshow

Learning Objectives

• By the end of lecture , students should be able to know:
  • Define masticationRecognize the role of mastication in digestion process.
  • Outline the reflex arc of mastication

Mastication or chewing is the first mechanical process in the gastrointestinal (GI) tract, by which the food substances are torn or cut into small particles and crushed or ground into a soft bolus.

MUSCLES OF MASTICATION

1. Masseter muscle
2. Temporal muscle
3. Pterygoid muscles
4. Buccinator muscle.

Significance of Mastication

• Help in cutting & grinding action thus Cause Breakdown of foodstuffs into smaller particles
• Mixing of saliva with food substances thoroughly.
• Lubrication and moistening of dry food so it can easily be swallowed
• Appreciation of taste of the food.
• Teeth
• Cheeks & tongue
• Saliva
• Tongue

Chewing Reflex/ mastication reflex

• Stimulus : Presence of food in mouth
• Afferent : Through trigeminal nerve,
• Centre : Nuclei in brain stem (medulla) and cerebral cortex
• Efferent : Motor part (Mandible division) of trigeminal nerve(5^th cranial nerve)
• Effectors : Muscles of mastication
• (Masseter, temporalis, pterygoids, buccinators)
• Movements: Closure & opening of mouth, rotational movement, protraction and retraction of jaw