1. Oral Cavity and Pharynx
Prof. K. Sivapalan.

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

3. 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

4. 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

5. 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

6. 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

7. Oral Cavity and Pharynx
2013
Oral Cavity and Pharynx

8. 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