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Mastication(chewing) The teeth are designed for chewing. Chewing reflex * Presence of a bolus of food in the mouth * Initiates reflex inhibition of the.

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Presentation on theme: "Mastication(chewing) The teeth are designed for chewing. Chewing reflex * Presence of a bolus of food in the mouth * Initiates reflex inhibition of the."— Presentation transcript:

1 Mastication(chewing) The teeth are designed for chewing. Chewing reflex * Presence of a bolus of food in the mouth * Initiates reflex inhibition of the muscles of mastication * Lower jaw drops. * Initiates a stretch reflex of the jaw muscles * Rebound contraction. * Automatically Jaw raised * Closure of the teeth * Compresses the bolus again against the linings of the mouth

2 Neural Control * Muscles of chewing - innervated by the motor branch of the fifth cranial nerve. * The chewing process is controlled by nuclei in the brain stem. * Stimulation of specific reticular areas in the brain stem taste centers - rhythmical chewing movements. Stimulation of areas in the * Hypothalamus, Amygdala, and even the Cerebral cortex near the sensory areas for taste and smell cause chewing.

3 Functions of Mastication * Chewing is important for digestion of fruits and raw vegetables – Indigestible cellulose membranes around their nutrient portions that must be broken * Digestive enzymes act only on the surfaces of food particles * Rate of digestion increased (Dependent on the total surface area exposed to the digestive secretions) * Prevents excoriation of the gastrointestinal tract

4 Salivary Secretion Saliva is secreted by Parotid gland Sub mandibular gland Sub lingual gland Buccal glands

5 Saliva Saliva contains two major types of protein secretion Serous secretion (ptyalin) Mucus secretion (mucin)

6 Saliva has a pH between 6.0 and 7.0. Daily secretion of saliva is between 800ml and 1500ml (average 1000ml)

7

8 Regulation of salivary secretion


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