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2. Saliva

 Saliva is a watery fluid secreted by the salivary glands.
 It contains a type of enzyme called the salivary amylase, which converts
starch into simple sugars (such as maltose and dextrin).
 It also acts as a lubricant that makes food slippery and easy to swallow.

3. Tongue

The tongue is a muscular organ. It can roll in any direction.

Functions

 Tongue helps to mix saliva in the food.
 It also helps to push the food down the food-pipe or oesophagus.
 There are large number of small bud-like structures present on our tongue.
These are called taste buds
 These are sensory organs and detect different tastes such as sweet, salt,
sour, and bitter.

4. Teeth

Structure of tooth

The outer part of the tooth is called enamel and is the hardest substance found in
our body. The visible part of tooth present above the gums is called the crown.

Human beings have two sets of teeth in their lifetime. These are temporary set of
teeth (milk teeth) and permanent set of teeth.