Читать книгу Basic Guide to Oral Health Education and Promotion - Alison Chapman - Страница 59

There are eight main functions of saliva:

1 Aids mastication and deglutition – mucous helps form the food bolus.

2 Oral hygiene – washing and antibacterial action helps control disease of the oral cavity. Lysozyme controls bacterial growth. This is why saliva is said to have antibacterial properties, and why animals instinctively lick their wounds.

3 Speech – a lubricant. For example, nervousness = production of adrenaline = reduction in saliva = dry mouth.

4 Taste – saliva dissolves substances and allows the taste buds to recognise taste.

5 Helps maintain water balance (of body) – when water balance is low, saliva is reduced, producing thirst.

6 Excretion – trace amounts of urea and uric acid (a minor role in total body excretion).

7 Digestion – salivary amylase begins the breakdown of cooked starch (a relatively minor role in the whole digestive process, but important in relation to sucrose intake and oral disease).

8 Buffering action – helps maintain the neutral pH of the mouth. The bicarbonate ion is vital to the health of the mouth as it is concerned with the buffering action of saliva. The average resting pH of the mouth (when no food has just been consumed) is 6.7. This is neutral, neither acid nor alkaline. (pH is a symbol used to indicate measurement of acidity or alkalinity of substances or liquids, and stands for the German term potenz Hydrogen.)