Presentation on theme: "Oral Cavity and Pharynx Prof. K. Sivapalan.. 2013Oral Cavity and Pharynx2 Salivary Glands Parotid – Serous [25 %] Sub Maxillary – Mixed [70 %] Sub Lingual,"— Presentation transcript:
2013Oral Cavity and Pharynx2 Salivary Glands Parotid – Serous [25 %] Sub Maxillary – Mixed [70 %] Sub Lingual, Buccal – mucus. [5 %] Basal secretion – 0.25 ml / min, 1500 ml/day.
2013Oral Cavity and Pharynx3 Contents of Saliva pH- 7 at rest, 8 active secretion. Buffers: bicarbonate, phosphate, mucin. Enzymes: –Lingual lipase – glands on tongue. –Salivary amylase. Mucins [Glycoproteins] IgA. Lyzozyme Lactoferrin – binds Fe and bacteriostatic. Proline rich proteins – protect enamel and bind toxic substances. Na +, K +, Cl -, and HCO 3 - equal to plasma at high flow. Low Na + and high K + at rest. Exchange controlled by aldosteron.
2013Oral Cavity and Pharynx4 Functions of saliva. Moistening and Lubrication –speech, mastication, deglutition. Facilitating sense of Taste. Maintaining Oral hygiene –Lyzozyme, IgA, enzymes, flow. Protection of teeth – enzymes, pH, Ca. –[Causes of Dental caries.] Neutralization of gastric acid.
2013Oral Cavity and Pharynx5 Control of Salivary Secretion. Stimuli: –Higher centers [thought, sight, smell- conditioned reflex] –Touch- smooth objects [most] –Taste- bitter [most] –Stomach- irritation Afferents Centre- salivary nucleus. Efferent- Parasympathetic. Sympathetic activity- inhibition [dry mouth in excitement]
2013Oral Cavity and Pharynx6 Mastication Force at the incisors is 55 pounds and molars is 200 pounds. Purpose: increase surface area for enzyme action and facilitate movement through GIT [differences between processed and naturally occurring food] Voluntary action but Chewing reflex occurs. Chewing movements can be produced by stimulating: –Reticular formation of hind brain –Hypothalamus –Amygdaloid nuclei –Cerebral cortex near area for taste and smell