1. School of Dentistry, Tongji University
Oral physiology
Oral Function
ZHANG LEI
School of Dentistry, Tongji University

2. Swallowing Swallowing:
move food and liquid from the mouth to the stomach; a very complex reflex process.

3. Process of swallowing I. Oral preparatory phase:
the food is chewed and mixed with saliva to form a moist, cohesive bolus ready to be swallowed.
II. Pharyngeal phase:
When the food bolus comes into contact with the mucosa of the pharynx and larynx , it activates mucosal mechanoreceptors, hence activate many muscles that are involved in swallowing. The next event in this complex sequence of events is the inhibition of respiration.
III. Oesophageal phase:
Once in the oesophagus, the food bolus is propelled towards the stomach by peristalsis (partly controlled by the vagus nerve)

4. Speech
Speech denote the peripheral processes that are needed to produce spoken language, it is a motor activity and consequently can be mapped onto anatomical structures of the articulatory tract.

5. Functional subsystems of motor speech
I. Respiration:
II. Phonation (sound production):
III. Resonance:
IV. Articulation:

6. Saliva Saliva glands: Parotid gland: 22-30%
Submandibular gland: 60-65%
Sublingual gland: 2-4%
Minor glands: 7-8%

7. Composition of saliva Daily production: 1-1.5 L (0.5 ml/min)
Density:
pH: (6.75)
Water: 99.4%
Inorganic: 0.2%
Organic: 0.4%

8. Inorganic saliva composition

9. Organic saliva composition
Proteins:
1) Digestive enzymes:
α-amylase: hydrolyses the α-1,4 glycosidic linkages of starch molecules
Lipase: an enzyme able to break down dietary triglycerides.
2) Proteins with lubricating functions: Mucins(粘蛋白)
3) Calcium binding proteins: statherin（富酪蛋白）
4) Carbon dioxide hydration:
Carbonic anhydrase: catalyse the reversible hydration of CO2. to carbonic acid.
5) Saliva proteins with antimicrobial functions:
secretory IgA (sIgA), mucins, lysozyme and lactoferrin（乳铁蛋白）.
6) Growth factors in saliva:
epidermal growth factor (EGF) , Transforming growth factors (TGF-a and TGF-P) , fibroblast growth factor (FGF)

10. Saliva functions

11. Saliva functions Saliva buffer capacity
The ability of the saliva to maintain the pH when exposed to acids is termed buffer capacity.
Buffer systems in saliva:
1. The bicarbonate buffer system CA CA
CO2+H2O H2CO HO3- + H+
2. The phosphate buffer system

12. Sensation:taste
All animals including humans respond to chemical stimuli through specialized chemosensory systems such as taste and smell.

13. Sensation:taste
Taste papillae in humans come in at least 4 different shapes and are located on the tongue, soft and hard palate, pharynx, epiglottis and larynx.

14. Sensation:taste
Sensibility of different portions of the tongue varies:
Top: more sensible to sweet
Lateral: sour
Base: bitter
Palate: sour, bitter

15. Pain Thermal sensation
Other sensations
Pain Thermal sensation

16. “…with the changing patterns of dental practice consequent upon the declining prevalence of dental caries, the more complex needs and expectations of the patient will hinge upon a much greater knowledge of oral physiology.” C.L.B. Lavelle