Saliva is clear liquid made by Salivary glands in mouth. It contains small amount of important substances like mucus, proteins, minerals, electrolytes, anti-bacterial compounds and enzymes. It's secretion is controlled by Automatic nervous system.
Saliva serves various functions to ease the digestion of food that we consume. Amylase, enzyme present in Saliva, begins the breakdown of polysaccharides to disaccharide maltose. High water content of Saliva lubricates the dry food, entering the mouth and made it ready for swallowing.
Lysozyme and immuno globins (anti-bodies) present in Saliva resist the invading microbes entering our body via oral route. The taste buds in mouth are also stimulated by chemical substances present in Saliva, therefore, we can taste food only after thorough mixing with blue secretion of Saliva occurs when there is food in the mouth. Sometimes, saliva also secretes with sight, smell and even with thought of food.