Function of the Mouth

Mouth Functions

The mouth is basically defined as a key part of the digestive system, but this is not the only role that it plays. The main functions of the mouth include mastication, tasting foods, and speech. The mouth anatomy is also an important element of our appearance. These functions are performed with the synchronized operation of the many different parts of the mouth.

What is the Function of the Mouth?

The various parts of our mouth contribute to the following functions of the human body:

Mastication (chewing)

The mouth serves for the intake and preparation of food for the digestive process. It breaks food into small particles and moves it into the pharynx. Teeth hold, cut, tear, and grind our food. Without teeth, we could eat only soft foods. Although the main task of chewing and grinding the food is done by our teeth, several other parts of the mouth contribute to this function.

  • Lips and cheeks hold food in the mouth and, with the help of the tongue, put food between teeth for chewing.
  • The mouth muscles and the movement of the jaw are also necessary for proper mastication.
  • Saliva moistens and softens food to facilitate chewing and swallowing. It initiates the chemical digestion of food with the enzymes it contains.
  • The tongue moves food around the mouth while we chew and finally gathers the chewed food into a ball (bolus), before moving it at the back of the mouth for swallowing.

Chewing ability is essential for human health. Functional mouth problems, e.g. tooth loss, can seriously alter a person’s diet, not allowing proper nutrition, causing general health problems and significantly reducing quality of life.


The tongue is much more than a strong muscle used for moving the food in the mouth. It is the key organ for the sensation of taste. The tongue is capable of tasting four main types of flavors: sweet, sour, bitter, and salty.

Around 10.000 small bulblike sensory structures located at the sides and base of the tongue, called "taste buds", enable us to distinguish flavors and warn us when food is unfit to eat.


The mouth is essential for speech. With the relative positioning of our teeth, lips, cheeks, and tongue we can control the air flow through the mouth creating different sounds and forming words when we speak. This alteration of the inner shape of the mouth in combination with the position of the lips modifies the sounds produced by the vocal cords in such a way that they become recognizable as speech.

Orthodontic anomalies and loss of one or more front teeth may alter our ability to speak properly and clearly, causing a lisp. Our mouth, especially the lips, is needed for whistling, singing, and playing wind musical instruments.


The shape of our mouth, jaws, lips, and teeth together contribute in the appearance of our face. Irregularities of any part of the mouth can negatively affect the way we look. Crooked, discolored, or missing front teeth are some common examples that cause problems with a person’s appearance.


Facial expressions, which are an important part of human behavioral communication, are another function of the mouth. A smile is the most common one. The smile and other expressions such as kissing, laughing, frowning, or baring teeth are formed by the movement of lips and cheeks by the facial muscles.


Normally, breathing is performed through the nose. However, in cases when nose breathing is inadequate e.g. when running, or if nose is blocked when we have a cold, the mouth can be used alternatively for the intake of the air required for breathing.

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