If all that wasn’t enough, your tongue even helps keep you from getting sick. The back section of your tongue contains something called the lingual tonsil (say: ling-gwul tahn-sul). Lingual is a medical word that means having to do with the tongue, and tonsils are small masses of tissue that contain cells that help filter out harmful germs that could cause an infection in the body.
But when you have tonsillitis, it’s not your lingual tonsil that’s infected. Tonsillitis affects the palatine (say: pah-luh-tyne) tonsils, which are two balls of tissue on either side of the tongue. The lingual tonsil, the palatine tonsils, and the adenoids are part of a bigger system that fights infections throughout your body.
Friend of the Tongue
Last time you had a cold and your nose felt stuffed up, did you notice that foods didn’t taste as strong as they usually do? Well, that’s because your tongue can’t take all of the credit for tasting different flavors — it has help from your nose.
Your nose helps you taste foods by smelling them before they go in your mouth and as you chew and swallow them. Strong smells can even confuse your taste buds: Try holding an onion slice under your nose while eating an apple. What do you taste?
Your tongue also gets help from your teeth, lips, and mouth. Your teeth help your tongue grind food as the tongue mixes the food around your mouth. And without your teeth, lips, and the roof of your mouth, your tongue wouldn’t be able to form sounds to make words.
Saliva is also a friend of the tongue. A dry tongue can’t taste a thing, so saliva helps the tongue by keeping it wet. Saliva moistens food and helps to break it down, which makes it easier for the tongue to push the food back to swallow it.
Don’t put that mirror away yet! Look at your tongue again, but this time look closely at the top of it. Notice how it’s rough and bumpy — not like the underside, which is very smooth. That’s because the top of your tongue is covered with a layer of bumps called papillae (say: puh-pih-lee).
Papillae help grip food and move it around while you chew. And they contain your taste buds, so you can taste everything from apples to zucchini! People are born with about 10,000 taste buds. But as a person ages, some of his or her taste buds die. (An old person may only have 5,000 taste buds!) That’s why some foods may taste stronger to you than they do to an adult. Taste buds can detect sweet, sour, bitter, and salty flavors.
Tongue Held Down Tight
Have you ever wondered what keeps you from swallowing your tongue? Look in the mirror at what’s under your tongue and you’ll see your frenulum (say: fren-yuh-lum). This is a membrane (a thin layer of tissue) that connects your tongue to the bottom of your mouth. In fact, the whole base of your tongue is firmly anchored to the bottom of your mouth, so you could never swallow your tongue even if you tried!
Has anyone ever told you that the tongue is a muscle? Well, that’s only partly true: The tongue is really made up of many groups of muscles. These muscles run in different directions to carry out all the tongue’s jobs.
The front part of the tongue is very flexible and can move around a lot, working with the teeth to create different types of words. This part also helps you eat by helping to move food around your mouth while you chew. Your tongue pushes the food to your back teeth so the teeth can grind it up.
The muscles in the back of your tongue help you make certain sounds, like the letters “k” and hard “g” (like in the word “go”). Try saying these letters slowly, and you’ll feel how the back of your tongue moves against the top of your mouth to create the sounds.
The back of your tongue is important for eating as well. Once the food is all ground up and mixed with saliva (say: suh-lye-vuh), or spit, the back muscles start to work. They move and push a small bit of food along with saliva into your esophagus (say: ih-sah-fuh-gus), which is a food pipe that leads from your throat to your stomach.
•Cavities and tooth decay. When bacteria and food particles stick to the teeth, plaque forms. The bacteria digest the carbohydrates in the food and produce acid, which dissolves the tooth’s enamel and causes a cavity. If the cavity isn’t treated, the decay process progresses to involve the dentin. Without treatment, serious infections can occur. The most common ways to treat cavities and more serious tooth decay problems are: filling the cavity; performing root canal therapy, involving the removal of the pulp of a tooth; crowning a tooth with a cap that looks like a tooth made of metal, porcelain, or plastic; or removing or replacing the tooth. A common cause of tooth decay in toddlers is “baby bottle tooth decay,” which occurs when a child goes to sleep with a milk or juice bottle in the mouth and the teeth are bathed in sugary liquid for an extended period of time. To avoid tooth decay and cavities, teach your kids good dental habits — including proper tooth-brushing techniques — at an early age.
•Impacted wisdom teeth. In many people, the wisdom teeth are unable to erupt normally so they either remain below the jawline or don’t grow in properly. Dentists call these teeth impacted. Wisdom teeth usually become impacted because the jaw isn’t large enough to accommodate all the teeth that are growing in and the mouth becomes overcrowded. Impacted teeth can damage other teeth or become painful and infected. Dentists can check if a person has impacted wisdom teeth by taking X-rays of the teeth. If the X-rays show there’s a chance that impacted teeth may cause problems, the dentist may recommend that the tooth or teeth be extracted.
•Malocclusion is the failure of the teeth in the upper and lower jaws to meet properly. Types of malocclusion include overbite, underbite, and crowding. Most conditions can be corrected with braces, which are metal or clear ceramic brackets bonded to the front of each tooth. The wires connecting braces are tightened periodically to force the teeth to move into the correct position.
•Aphthous stomatitis (canker sores). A common form of mouth ulcer, canker sores occur in women more often than in men. Although their cause isn’t completely understood, mouth injuries, stress, dietary deficiencies, hormonal changes (such as the menstrual cycle), or food allergies can trigger them. They usually appear on the inner surface of the cheeks or lips, under the tongue, on the soft palate, or at the base of the gums. They begin with a tingling or burning sensation followed by a painful sore called an ulcer. Pain subsides in 7 to 10 days, with complete healing usually occurring in 1 to 3 weeks.
•Cleft lip and cleft palate are birth defects in which the tissues of the lip and/or mouth don’t form properly during fetal development. Children born with these disorders may have trouble feeding immediately after birth. Reconstructive surgery in infancy and sometimes later can repair the anatomical defects, and can prevent or lessen the severity of speech problems later on.
•Enteroviral stomatitis is a common childhood infection caused by a family of viruses called the enteroviruses. An important member of this family is coxsackievirus, which causes hand, foot, and mouth disease. Enteroviral stomatitis is marked by small, painful ulcers in the mouth that may decrease a child’s desire to eat and drink and put him or her at risk for dehydration.
•Herpetic stomatitis (oral herpes). Kids can get a mouth infection with the herpes simplex virus from an adult or another child who has it. The resulting painful, clustered vesicles, or blisters, can make it difficult to drink or eat, which can lead to dehydration, especially in a young child.
•Periodontal disease. The gums and bones supporting the teeth are subject to disease. A common periodontal disease is gingivitis — inflammation of the gums characterized by redness, swelling, and sometimes bleeding. The accumulation of tartar (a hardened film of food particles and bacteria that builds up on teeth) usually causes this condition, and it’s almost always the result of inadequate brushing and flossing. When gingivitis isn’t treated, it can lead to periodontitis, in which the gums loosen around the teeth and pockets of bacteria and pus form, sometimes damaging the supporting bone and causing tooth loss.
The first step of digestion involves the mouth and teeth. Food enters the mouth and is immediately broken down into smaller pieces by our teeth. Each type of tooth serves a different function in the chewing process. Incisors cut foods when you bite into them. The sharper and longer canines tear food. The premolars, which are flatter than the canines, grind and mash food. Molars, with their points and grooves, are responsible for the most vigorous chewing. All the while, the tongue helps to push the food up against our teeth.
During chewing salivary glands in the walls and floor of the mouth secrete saliva, which moistens the food and helps break it down even more. Saliva makes it easier to chew and swallow foods (especially dry foods), and it contains enzymes that aid in the digestion of carbohydrates.
Once food has been converted into a soft, moist mass, it’s pushed into the throat (or pharynx) at the back of the mouth and is swallowed. When we swallow, the soft palate closes off the nasal passages from the throat to prevent food from entering the nose.
The entrance to the digestive tract, the mouth is lined with mucous membranes. 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 and the nasal passages above. The soft palate forms a curtain between the mouth and the throat, or pharynx, to the rear. The soft palate contains the uvula, the dangling flesh 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 bumps called papillae. These contain tiny pores that are our taste buds. Four main kinds of taste buds are found on the tongue — those that sense sweet, salty, sour, and bitter tastes. Three pairs of salivary glands 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, allows for the lips’ mobility. The reddish tint of the lips comes from underlying blood vessels. The inside portion of both lips is connected to the gums.
There are several types of teeth. Incisors are the squarish, sharp-edged teeth in the front of the mouth. There are four on the bottom and four on the top. On either side of the incisors are the sharp canines. The upper canines are sometimes called eyeteeth. Behind the canines are the premolars, or bicuspids. There are two sets, or four premolars, in each jaw.
The molars, situated behind the premolars, have points and grooves. There are 12 molars — three sets in each jaw called the first, second, and third molars. The third molars are the wisdom teeth, thought by some to have evolved thousands of years ago when human diets consisted of mostly raw foods that required extra chewing power. But because they can crowd out the other teeth or cause problems like pain or infection, a dentist might need to remove them.
Human teeth are made up of four different types of tissue: pulp, dentin, enamel, and cementum. The pulp is the innermost portion of the tooth and consists of connective tissue, nerves, and blood vessels, which nourish the tooth. The pulp has two parts — the pulp chamber, which lies in the crown, and the root canal, which is in the root of the tooth. Blood vessels and nerves enter the root through a small hole in its tip and extend through the canal into the pulp chamber.
Dentin surrounds the pulp. A hard yellow substance, it makes up most of the tooth and is as hard as bone. It’s the dentin that gives teeth their yellowish tint. Enamel, the hardest tissue in the body, covers the dentin and forms the outermost layer of the crown. It enables the tooth to withstand the pressure of chewing and protects it from harmful bacteria and changes in temperature from hot and cold foods. Both the dentin and pulp extend into the root. A bony layer of cementum covers the outside of the root, under the gum line, and holds the tooth in place within the jawbone. Cementum is also as hard as bone.