Mouth

The mouth is the start of the digestive system. The few parts in the mouth are teeth, saliva, and the tongue.

Teeth

The human body has 2 sets of teeth. The first set of 20 teeth grows from about birth to 3 years of age. These are called baby or milk teeth. At about 6 years of age, the first set of teeth begin to drop naturally as they are replaced by a second set called adult or permanent teeth. Most people have 32 adult teeth. There are 4 different types of teeth.

•  Your front teeth are called the incisors. They bite off large food items. 
  
• Behind them are canines. These teeth are used to tear up though food. The canines are taller and more pointed compared to the incisors.
• Next in line is the pre-molars which are used for squashing and crushing food. The pre-molars are wider than both the incisors and the canines.
• At the rear of the mouth are the molars. They are used for chewing. The molars are the broadest teeth.
  

Saliva

Saliva contains a type of enzyme called amylase. This enzyme breaks apart starch. This is why when we chew starchy foods like bread, potatoes, pasta or rice, we can sometimes taste them becoming sweeter.

Tongue

The tongue taste food so that we know what we are eating. It can tell us when a food is rotten when it taste bitter. The tongue also shifts bits of food stuck among the teeth.

After the food is chewed into soft paste by the teeth, it is swallowed and continues on its digestive journey.