Saliva, its Composition and Functions


Saliva is a watery fluid that is clear, transparent, slightly acidic in nature secreted in oral cavity of mouth through Salivary glands.

  • Saliva is a fluid that is secreted from major salivary glands that are located at the front of the ear or at the floor of the mouth.
  • Parotid gland is the largest salivary gland located at the front of the ear secretes the saliva and transported through the duct at the floor of the mouth.
  • Submandibular and Submaxillary are the other major salivary glands which secretes the saliva under the tongue.
  • Some minor salivary glands found in the cheeks, lower lips, palate and pharynx.
  • Minor salivary glands have the major protective functions and major salivary glands have the quantitative functions.
The average daily production of the saliva is varies between 1 to 1.5 litre.

Total secretion is like as 20% form parotid gland, 65% from mandibular, 8% from sublingual gland and 10% from some of other minor glands.

Composition of Saliva

saliva composition

Saliva is composed of different types of components which contains both organic and inorganic compounds.
Saliva contains many electrolytes, proteins, enzymes, immunoglobulins and gases.
All theses components play an important role in the digestion as well as protective functions of the oral cavity of the mouth.
  1. Bicarbonates, Phosphates and urea act as buffer and modulate the pH of the saliva.
  2. Immunoglobulins, enzymes, proteins provides the antibacterial action by killing the small microbes comes with the food we eat.
  3. Calcium, phosphates, proteins work together for demineralization and remineralization.
Saliva is fluid which is composed of 99.5% water and rest of the solids in the form of organic and inorganic compounds.

The normal pH of saliva is between 5 to 7 it means it is slightly acidic in nature.

Functions of Saliva

  1. Saliva is essential for the digestion of the food and also for the maintenance of the oral hygiene of the mouth.                             
  2. Without saliva digestion of the food is not process, swallowing problems and oral infection are more common.                              
  3. Lubricant function- saliva act as a lubricant makes the food wet and protect the inner membrane by injury and reduces friction during eating, swallowing and speaking.
  4. Absence of saliva in mouth is called Xerostomia and food sticks inside the mouth and causes injury of the inner lining of the mouth.
  5. Digestive function- saliva contains the various types of enzymes, proteins which makes the food into simpler form from complex compounds.
  6.  Saliva contains the enzyme amylase or ptyalin which breaks down the starch into simpler sugar which can be easily absorbed into small intestine.
  7. Salivary lipase plays an important role in the digestion of the food in infants.
  8. Taste- saliva contains chemicals that which are carried to the taste receptors cells to the higher centers.
  9. Antibacterial function- saliva contains antibodies and immunoglobulins which kills the microbes in the mouth itself.

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