The oral cavity. The mouth is defined by four structures: the hard palate, the bony structure that is the roof of the mouth; the soft palate, the arch-shaped structure at the back of the mouth composed of muscle; the uvula, the cone-shaped structure hanging down from the soft palate; and
the tongue and its muscles, which form the floor of the mouth.
The teeth and the tongue are accessory structures of the mouth. The tongue functions to move chewed food to the back of the mouth. It has a characteristic rough surface due to small structures called papillae. Taste buds are microscopic nerve endings within the papillae.
Teeth are locked into the socket of the lower and upper jaw. By the time a person reaches the age of 17 to 24 he or she will usually have a full set of 32 teeth. The function of biting off pieces of food and pulverizing it during chewing is aided by saliva, fluid secreted by glands in or around the mouth. Up to a liter of saliva is secreted daily to lubricate food particles and to initiate starch digestion.