The mouth is lined with mucous membranes that protect the inside of your mouth and keep it moist. If the proper moisture level is not maintained, problems can result. This could be 'dry mouth', an abundance of bacteria because it is not being washed away properly, or a number of other problems.

To keep the mouth moist there are three pairs of salivary glands in the walls and floor of the mouth. They secrete saliva, which contains a digestive enzyme called amylase that starts the breakdown of carbohydrates even before food enters the stomach.

The tongue is mostly muscle. It is covered with a mucous membrane.

Top of the Tongue

The top side of the tongue is called the dorsum and can be divided into two parts: the front that lies mostly in the mouth (anterior), and a back part that faces backwards (posterior). The anterior makes up two thirds of the tongue, with the posterior making the final third.

The front and back parts are separated by a V-shaped groove, called the sulcus terminalis (or terminal sulcus). The line down the middle of this is called a median furrow.

The top surface of the tongue is covered with bumps. These are called papillae; they are not the taste buds