Three pairs of salivary glands exist in man while in rabbit they are four pairs. In man, the three pairs are parotid, submaxillary and sublingual glands. They all have ducts leading to the mouth cavity. They secrete digestive juice called saliva. Saliva contains an enzyme called ptyalin, mucin and water. The smell, sight and taste of food stimulate the secretion of saliva.
- Saliva protects the soft lining of the mouth from drying up.
- The watery parts of the saliva help to dissolve dry food substances.
- The mucin lubricates the chewed food and makes the food particles stick together to form bolus for easy swallowing.
- It helps in cleaning the mouth.
- It helps in speech by wetting the tongue, hard palate and lips so that the tongue does not stick to the roof of the mouth.
- Saliva being alkaline helps to neutralise the acids produced by bacteria during the fermentation of food particles left over between the teeth.