Mouth and teeth

he first thing that comes to mind when you think of your mouth is probably eating — or kissing! But your mouth's a lot more than an input slot for food or a tool for smooching your sweetie.

Where Would We Be Without Them?

Your mouth and teeth form your smile, which is often the first thing people notice when they look at you. The mouth is also essential for speech: The tongue (which also allows us to taste) enables us to form words with the help of our lips and teeth. The tongue hits the teeth to make certain sounds — the th sound, for example, is produced when the tongue brushes against the upper row of teeth. If a person has a lisp, that means the tongue touches the teeth instead of directly behind them when saying words with the s sound.

Without our teeth, we'd have to live on a liquid diet or a diet of soft, mashed food. The hardest substances in the body, the teeth are necessary for mastication — a fancy way of saying chewing — the process by which we tear, cut, and grind food in preparation for swallowing. Chewing allows enzymes and lubricants released in the mouth to further digest, or break down, food. This makes the mouth one of the first steps in the digestive process. Read on to find out how each aspect of the mouth and teeth plays a role in our daily lives.

Basic Anatomy of the Mouth and Teeth

The mouth is lined with mucous membranes (pronounced: myoo-kus mem-branes). Just as skin lines and protects the outside of the body, mucous membranes line and protect the inside. Mucous membranes make mucus, which keeps them moist.

The membrane-covered roof of the mouth is called the palate. The front part consists of a bony portion called the hard palate, with a fleshy rear part called the soft palate. The hard palate divides the mouth from the nose above. The soft palate forms a curtain between the mouth and the throat (or pharynx — pronounced: fa-rinks) to the rear. The soft palate contains the uvula (pronounced: yoo-vyoo-luh), the dangling fleshy object at the back of the mouth. The tonsils are located on either side of the uvula and look like twin pillars holding up the opening to the pharynx.

A bundle of muscles extends from the floor of the mouth to form the tongue. The upper surface of the tongue is covered with tiny projections called papillae. Our taste buds are located here. The four main types of taste buds — sweet, salty, sour, and bitter — are found on the tongue.

Three pairs of salivary glands in the walls and floor of the mouth secrete saliva, which contains a digestive enzyme called amylase that starts the breakdown of carbohydrates even before food enters the stomach.

The lips are covered with skin on the outside and with slippery mucous membranes on the inside of the mouth. The major lip muscle, called the orbicularis oris (pronounced: or-bik-yoo-lar-iss or-iss), allows for the lips' mobility. The reddish tint of the lips comes from underlying blood vessels, which is why the lips can bleed so easily with injury. The inside part of the lips connects to the gums.

Welcome to listen to this article at http://kidshealth.org/teen/your_body/body_basics/mouth_teeth.html