The sight, smell and taste of food provoke the reflex secretion of saliva by the salivary glands. There are three pairs of salivary glands - the sublingual and submandibular glands shown in the diagram, and also the parotid glands in front of each ear.

Saliva contains an enzyme that starts the chemical breakdown of starch into sugars, but its main function is to moisten the food so that it can be swallowed more easily.