Mouth

What is the Mouth?

The mouth is the organ by which we eat food. It also helps in articulation and thus forms a very important organ for speech production. It starts with the lips on the outside and ends at the fibromuscular, funnel shaped organ called the pharynx. It contains the gums, teeth and the tongue in its cavity.

Where is the mouth situated?
The mouth or the oral fissure as it is called, is situated below the nose and in the center of our face. It has the cheeks as the walls of its cavity. Cheeks are made mainly of a muscle called as the buccinator that helps us to puff our cheeks and blow out. The roof is formed in the front by the bony hard palate and at the rear end by softer tissue called the soft palate. The floor of the mouth is formed by the tongue and the soft lining of the floor of the mouth called the buccal mucosa.

How can we describe the mouth?

The mouth can be described as a hollow structure lined by smooth tissue called as mucus membrane. The gums and the teeth are contained in the oral cavity.

Lips : Externally the mouth begins at muscular folds called as lips. They are a continuation of the buccal mucosa of the mouth. They have thin covering of mucosa over them and hence appear pink or red.

Gums : Gums are hard masses of tough tissue and act as holders for our teeth. They are cup shaped and have a socket for the teeth to fit in. They are present around the teeth also and hold the root of the tooth. This contains a lot of nerve endings and so there is a lot of pain during a toothache. The stability of the teeth depends on the strength of the gums holding them. Improper care and negligence of the gums leads to tooth loss and dental caries.

Teeth : There are two sets of teeth during a human lifetime. The first set called the milk teeth or the deciduous teeth are temporary and seen in small children. They are twenty in number. By the age of twelve, they fall giving rise to permanent teeth, which are thirty-two in number. Between the ages of seventeen and twenty five, the wisdom teeth or the third molars appear.

Tongue : The tongue is a bundle of muscle. It is covered by mucus membrane. The initial two-thirds of the tongue lies in the mouth while the rear one-third lies in the fibromuscular tube called pharynx. The tongue is the primary organ for the sense of taste. The tongue has two types of muscles; The first group is called the intrinsic group, which resides within the tongue itself and is not attached to the bone. This group of muscles alters the shape of the tongue that helps in chewing of food and speech. The second group of muscles is attached to the soft palate and which provide stability and movement to the tongue.

The tongue has structures called papillae on its surface that impart roughness to the tongue. These are small mushroom like projections and are of varying sizes. They are present throughout the tongue, mainly on the surface of the tongue. The taste buds, which distinguish various tastes, are usually present around these papillae.

Saliva : The mouth also contains fluid called saliva. The saliva is not just plain watery fluid. It contains enzymes that help in digestion of starch in our food. Saliva is produced mainly by the parotid gland, a sac of tissue which lies behind and partly beneath the visible ear. Glands in the mouth also produce saliva. These are the submandibular gland, which lies below the mandible or jaw, and the sublingual gland, which lies beneath the tongue.

Now that we know the structure of the mouth we will see what is its role in the human body.

Functions of the Mouth

The mouth has a number of functions. These are:

• Chewing of food : The teeth, tongue and the saliva work together in chewing, also called as mastication of food. The saliva softens the food while the teeth cut and grind it. The tongue rolls the food in the oral cavity to ensure proper mastication.
• Tasting the food : The tongue helps in tasting food. It also helps in swallowing a bolus of food. During swallowing, the tongue pushes the bolus of food towards the esophagus or food pipe and simultaneously the epiglottis closes the opening to the respiratory tract, thus preventing entrance of food into the larynx.
• Speech and Articulation : One of the major functions of the mouth is speech and articulation. The tongue is very flexible because of the presence of muscles in it. This helps in moving the tongue against the teeth and giving meaning to the sound produced by the larynx.