Function of Saliva

Saliva

Saliva is an extracellular fluid that produced and secreted in mouth by salivary glands.

Salivary glands are -

1. Parotid gland

2. Submandibular gland

3. Subliminal gland

Saliva is contains over 99% water and electrolytes, mucus, white blood cells, epithelial cells, enzymes, (enzyme amylase, also called ptyalin) ,antimicrobial agents, serous, mucus forming proteins.

1. Amount- 6 salivary gland secrete; 1-1.5 litres saliva daily

2. pH of saliva; range between 5.8-7.4  acidic and alkaline (higher flow rate higher in pH)

Optimum pH of saliva; 6.8

Note - Not taking more food, not more production of saliva.

Composition of Saliva 

Saliva composed of 99% Water and 1% electrolytes is and protein .

Water (99%)

Mucus, Mucin

Serous

Protein

Salivary Amylase; nitiate digestion of starch

Salivary lipase/Lingual lipase; begin digestion of fat

Immunoglobulin; IgA

Lysozyme

Mineral salts; 

Sodium

Phosphates

Chlorides,  and

Bicarbonate

Urea uric acid

Function of Saliva

1. Lubrication of food

2. Cleansing action

3. Help in mastification; chewing and swallowing

4. Food Digestion, help in bolus formation

5. Smoother speech, lubricate tongue and lips during speech

6. Taste perception; taste bud

7. Lubricate passage of food down from oropharynx to esophagus to stomach

8. Blood clotting factor

9. Salivary amylase enzyme; break down of carbohydrates (polysaccharides)

10. Keep moist (maintaining health of oral cavity)

11. Dissolves food

12. Immune Defense/ antimicrobial action

13. Lubricate digestive tract

14. Buffering function

Regulation of Salivary Secretion

Saliva is spontaneous secretiin to keep mouth and throat moist

Secretion of saliva is under control and stimulated by the autonomic nervous system (sympathetic and parasympathetic), controls both volume and type of saliva secreted.

Control of Salivary Secretion

There are Two pathway-

1. Touch and taste of food in mouth

2. Thinking, seeing and smelling food