Tongue and taste

Wonders of the tongue are speech and taste. Everyone knows that a literate tongue and pen are the most powerful weapons of scholars. Its worth can be understood as one uses that the words 'mother tongue' for one's spoken the language. As a double-edged sword, any mistake of it or slip of the tongue can make one’s life miserable.

Tongue is a small muscular organ playing a major role in our life. It is one of the marvellous parts of our body which carries different functions in different manners. It is otherwise termed as glossal or lingual.

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Tongue has no skeleton for support. In spite of it all, it claims to be the most powerful muscle of our body in proportion to its size. With the tongue, food tastes good, of course life, too. As no doctor will miss one to say “Aaah” to see the tongue and throat, tongue postulates to be a display mirror of health status. Pink and clean tongue is supposed to be indicative of pink of health and free of diseases. In mammals, tongue is used as a tool for licking to show special affection.

Tongue – is approximately 10 cms long and 4 cms broad. It occupies and attaches to the floor of the mouth by frenulum (fold of mucous membrane). It is fitted in such a way that it can have free movement in all directions. It is guarded well with the jaw, teeth and palates.

Tongue is made up of striated muscles. Four pairs of intrinsic muscles help in formation of the shape. Extrinsic muscles help for attachments and movements. It is attached to hyoid bone, jaw bone and temporal bone of skull through extrinsic muscles.

The upper part of the tongue is rough in character to have good grip with food. The lower part is smooth and has blood vessels and sensitive nerves. The rough look of tongue is due to the papillae. Papillae are fur like structure in which taste buds are embedded or studded. Four types of papillae are present in the tongue. They are filiform, fungiform, foliate and vallate. They have taste buds on their surfaces. The oral part of the tongue has more taste buds than of pharynx part. The tongue is supplied by the facial nerve, glossopharngeal nerve and hypoglossal nerves. The former two carry sensations from the tongue and the later bring motor impulses from the brain to act.

Functions – As tongue remains freely movable in all directions, it can do all sorts of work. The tongue can also attain different shapes to do different jobs, i.e., it can get folded, flexed and rolled like an elephant trunk. Tongue functions are innumerous.

• It helps us to take our food / drink.

• It also helps in grinding the food (in mastication process) by directing the drinks as spatula.

• Also, it helps in swallowing (deglutition) by pushing the food bolus or drinks inside the throat.

• It can sense/detect even a minute unusual thing while masticating, i.e., hair, stones, sharp materials, etc, in the food, to get discarded.

• It spreads saliva throughout the mouth to maintain moisture in the mouth.

• The tongue usually maintains cleanliness of the mouth, cheek, teeth, gums, etc., with the help of saliva.

• When the tongue gets dry, it induces the brain to initiate impulse to take water with the sensation of thirst.

Against all the above said vital functions for survival and preventive measures, tongue especially works for communication (speech) and taste. The coordination of movement (of tongue) with speech and mastication process is invaluable. In case of lack of coordination, it can be caught in between the teeth and can be bitten.

• With training, it can speak fluently (even though speech is not only confined to tongue, without it, speech is impossible)

• Sharp tongue usually speaks well with better clarity.

• Further it can be used to whistle, blow, spit, etc.

• It can sense decomposed or non palatable food with taste and intimate the brain to avoid it. (Smell also plays a role here.)

• It can reject unwanted foods/drinks by triggering the brain to induce vomiting

• Touching/scratching the posterior part will be felt as an unpleasant feeling and it induces gag or vomiting.

Taste – is one of the special senses / feelings just like vision, hearing, smell, touch or pain. Taste differs from person to person, i.e., some people like to have sugar, some others would like sour things, some others would prefer salty stuff and yet others would prefer spicy food / bitter items. Likewise, some need a heap of sugar whereas some others need only a little amount to add taste. Normally, desires and aversions are developed with habits, i.e., what some find delicious others might find irritating.

Though bitter or salt or sour is not palatable as separate entity, they all can add taste to food. Their perfect combinations with food can make splendid tasty food. Likewise, some food tastes good while it is served hot, some others taste good while served cold, but all foods / drinks served in the extreme of temperatures usually induce / cause sensation of pain. Here again, tolerance to temperature differs from person to person, i.e., some take food very hot, some others prefer it to be medium and some prefer it cold. Occasionally, even medium hot food / drink can cause scalding to those who have cold food.

Nowadays, evolution of cooking and revolution of catering technology has been creating / introducing many varieties of food items claiming to be mouthwatering, delicious food. Feeling of taste is sensed by taste buds / receptors present all over the mouth in a scattered manner (i.e., in tongue, walls of cheek, gums, pharynx and soft palate). The chemical (specific) receptors in taste buds identify the particular taste and trigger the particular area in brain to have a pleasant or irritable feeling. These types of special sensations are carried to the brain by VII cranial nerve - facial nerve (from cheek and anterior 2/3 of tongue) and IX cranial nerve – glossopharngeal nerve (from posterior 1/3 of tongue, gums and pharynx).

Even though taste is not confined only to the tongue, the tongue is always blamed for any taste difference. Taste buds / receptors in the tongue are very much sensitive to temperature or disease, so even before the fever or disease manifests its full symptoms, taste or disgust for food (with aversion or appetite loss) emerges as the first symptom. The taste also differs with use of strong tooth paste, mouth fresheners, betel nut leaves, antibiotics, medicines, tobacco, cigarettes, etc. Likewise, in many disease conditions taste will become feeble or masked, i.e., in glossodynia (burning mouth syndrome), sjogren’s syndrome (dry mouth), glossitis, auto immune disorders, cancer patients, chemotherapy, radiation therapy, etc.

Tongue cleanliness – Mostly tongue maintains self cleanliness. It gets rinsed while drinking water and gets rubbed with hard and soft palate while masticating. Even though people brush their teeth daily, cleanliness of tongue is often ignored. If at all they care, they scrub it more to injure it or to get gags to clear throat. In case of coating or deposits of debris, it needs to be cleaned with a tongue wiper or scrapper or brush in a gentle manner to have taste at its best. Regular cleaning can help in avoiding plaque / debris deposits.

Examination – Tongue is often examined by doctors (mostly with every visit) to assess the patient's health status or problems. With retracted head, wide opened mouth, protruded tongue, the patient will be asked to say 'aahh' for clear vision of all the area of mouth including tongue and throat. Tongue will be examined for its size, colour, moisture, papillae, coating, ulcers, deformities, extra growth, venous engorgements, etc. Tongue will be dry in case of dehydration, pale in case of anaemia, discoloured in case of disease, smooth and glistening in case of ulcers.

Tongue and taste disorders –

(To be continued)