Oral Cavity and Pharynx Prof. K. Sivapalan.

Oral Cavity and Pharynx Salivary Glands Parotid – Serous [25 %] Sub Maxillary – Mixed [70 %] Sub Lingual, Buccal – mucus. [5 %] Basal secretion – 0.25 ml / min, 1500 ml/day. 2013 Oral Cavity and Pharynx

Oral Cavity and Pharynx 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 HCO3- equal to plasma at high flow. Low Na+ and high K+ at rest. Exchange controlled by aldosteron. 2013 Oral Cavity and Pharynx

Oral Cavity and Pharynx 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. 2013 Oral Cavity and Pharynx

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] 2013 Oral Cavity and Pharynx

Oral Cavity and Pharynx 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. 2013 Oral Cavity and Pharynx

Oral Cavity and Pharynx 2013 Oral Cavity and Pharynx

Oral Cavity and Pharynx Deglutition Voluntary Stage food pressed against pharynx Pharyngeal stage Afferents[5,9,10 CN] to deglutition centre, Efferents [5,9,10,12] Soft palate- close nasopharynx Palato-pharyngial folds- slit Larynx pulled up, vocal cord close, epiglottis fold back. pharyngeal muscles initiate peristalsis Upper and lower esophageal sphincters relax Food falls due to gravity before peristalsis reaches stomach when erect. 2013 Oral Cavity and Pharynx