Human Tongue Parts, Functions with Details and Diagram

Tongue – A Multifunction Tool

Did you ever think, without the tongue, you would have been unable to taste all the deliciousness of the natural world? Can the scientists create and install such a tool in your body which would make you taste things in the absence of tongue? Maybe the invention of such an instrument is possible, but it can never work as perfectly as your natural human tongue.

Human Tongue

Fig. 1: Human Tongue and its Parts


Tongue Definition

You can define tongue in different ways. For example, The Free Dictionary defines it as:

A small, fleshy and muscular organ attached to the floor of your mouth that helps in tasting, chewing, swallowing and speaking is called tongue.” [1]

According to Oxford Learners Dictionaries:

“Tongue is the soft part in your mouth that you move around and use it for taste, swallowing and speaking, etc.” [2]

Here is another tongue definition:

“A fleshy, movable muscular organ in the floor of the mouth of most vertebrates that contains sensory end organs and small glands and functions in taking and swallowing food, and also as a speech organ in humans.” [3]

(Merriam Webster Dictionary)

Considering the value of human tongue, this small muscular organ in your mouth cavity is a wonderful blessing of nature. In addition to providing a taste of the food, the tongue helps in manipulation of food for mastication. Its third important job is to help in the swallowing of meal.


Human Tongue Parts

The human tongue has three distinct divisions, namely, the apex, the body and the root. You can view the parts by having a side view of this extremely flexible muscular organ. The surface is divisible into anterior and posterior.

Below is the brief description of the major tongue parts:

The Tip or Apex

The tip or apex of the tongue accounts for one-third of the anterior surface of tongue. It is highly movable and rests against the incisor teeth in the mouth cavity. The taste buds for “sweet” are present on this part.

The tip also plays its role in the production of labiodental and alveolar sounds.

The Body or Main Part

The anterior two-thirds of the tongue form its body. The pres-ence of lingual papillae on the upper side makes the surface rough. A layer of mucosa, on the other hand, keeps it moist.

It is this part of the tongue where the tongue taste buds for salt, bitter and sour taste are present.

The Root or Base

The root is that part of the tongue which attaches it to the bottom or floor of the mouth cavity. It appears between the mandible and the hyoid bone. The pri-mary job of the hyoid bone is to provide anchorage to the tongue. [4]

The dorsal portion of the root lies in the oropharynx. What is oropharynx? It is the part of the pharynx lying between the soft palate and epiglottis. [5]


Tongue Anatomy

Occupying most of the oral cavity and oropharynx, your tongue is a mass of muscles. The specific arrangement of muscle fibers allows it to move freely in any direction inside the mouth cavity to performs several different tasks, including eating, swallowing, speaking, licking, sucking, oral cleansing, and catching pray, etc.

Tongue Anatomy

Fig. 2: Human Tongue Anatomy

You can distinguish between three tongue parts, the tip, the body and the base. The tip is highly mobile, anterior portion. Posterior to it lies the body which has ventral and dorsal surfaces. Next comes the base which attaches tongue to the floor of mouth.

The major aspects of tongue anatomy are being explained below:

Lingual Papillae on the Surface

Where does the tongue get its characteristic appearance? The lingual papillae on the surface of the organ are small bumps which contain taste buds. These projections of lamina propria are covered with tongue epithelium. [6]

Filiform, foliate, vallate and fungiform are the four different types of papillae found on the surface. Different papillae contain different number of taste buds. For example, a vallate papilla may contain 250 taste buds, while the number of taste buds may reach 1600 in the fungiform papilla. [7]

A taste receptor, edge and basal cells are found in each taste bud. Meanwhile, several nerve fibers innervate each taste bud.

Tongue Muscles

The musculature of tongue consists of four extrinsic and four intrinsic muscles. A fibrous septum separates the tongue muscles on each side. The intrinsic muscles originate from within the tongue body while extrinsic muscles have their origin outside the tongue body. [8]

Both types of muscles work in coordination to create various tongue movements. However, they have their individual roles as well. For example, the extrinsic muscles change the position of tongue while the intrinsic muscles alter its shape. [9]

Tongue Nerve Supply and Vasculature

The arterial blood supply for tongue comes from the external carotid artery. It branches off to join lingual artery which has three main branches, namely, the dorsal, the deep and the sublingual arteries. The branches of lingual artery supply blood to different parts of the tongue.

Turning to tongue nerve supply, the hypoglossal nerve provides most innervation for all the tongue muscles.


Tongue Surface

What are the tongue bumps? As you can observe in the tongue pictures, the human tongue has got a rough texture. It is because of the presence of tiny bumps, the tongue papillae, all over the dorsal surface of the tongue that make it look so rough.

Tongue Surface

Fig. 3: Tongue Surface

The surfaces of the tongue papillae, on the other hand, contain thousands of taste buds. The taste buds are actually a collection of the nerve-like cells. Nerves develop a connection between taste buds and the brain.

The upper most layer of tissue on the human tongue is that of mucosa. The mucosa keeps it moist. It also makes the tongue a bit slippery to touch.


Tongue Function

You spend so much money in making the food delicious. How do you taste deliciousness of the food? You owe this faculty to your tongue. In addition to detecting taste, the human tongue also performs several other important functions.

For example, the tongue function also involves the mastication of food, catching prey, licking, sucking and swallowing. Do you know any other interesting tongue function? The list of the some of the important tongue functions is given below:

Tongue – Tool to Taste Food

The ability of tongue to taste food is because of the presence of taste buds on its surface. According to traditional belief, different parts of the tongue sense only a specific taste.

The modern research rejects this belief. It suggests that different parts of tongue detect a specific taste more easily (and strongly) but they can detect other tastes as well. However, each receptor cell is sensitive to a particular taste only.

Different types of receptor cells help distinguish between various sorts of differently tasting substances, such as sweet, sour, bitter, spicy and salty. On the tip, you will find taste buds for sensing sweet.

Tongue – Tool to Taste Food

Fig. 4: Tongue - Tool to Taste Food

Behind the apex and along the sides, there are receptors for tasting bitter, sour and salty things.

Dorsum – the upper surface of the tongue – contains lots of lingual papillae. The papillae house the taste buds and the taste receptors. These receptors assist in the sensation of taste of different types of dietary components which come into contact with them.

The taste receptors are of five main types – sweet taste receptors, bitter taste receptors, salty taste receptors, sour taste receptors and umami taste receptors.

The umami taste receptors help you detect the taste of amino acids in the food.

Human Tongue’s Role in Mastication & Chewing

After the food enters the mouth cavity, two processes start and go side by side, grinding and mastication. During grinding, teeth break down the large food particles into smaller ones.

Thus, there is easy mixing of these particles with saliva to form bolus. Mastication involves the mixing of finely ground food with saliva. That is why you also call the process as chewing.

Tongue facilitates the process of mastication and chewing. Particularly, it helps in the positioning of food between the teeth. Secondly, as the food turns around, it is mixed with saliva.

The masticatory muscles provide the enormous strength of jaw closure. It is in large part due to the pinnated arrangement of fibers in the masseter. [10] The masseter is the masticatory muscle of the posterior cheek.

Removal of Hard and Ill-Tasting Substances

How do you take hard and unwanted substances out that accidently enter the mouth with food? Tongue has also a role in separating, sorting out and removing unsuitable particles that may accidently come with the food, such as bones and the ill-tasting soft or hard substances.

Swallowing Food

The masticated food forms a rounded mass, the bolus, with the help of tongue. The task of this fantastic muscular organ does not end here. Its next duty is to expel the bolus into esophagus at the back of the mouth cavity.

The food bolus then moves through the esophagus with the help of peristaltic contractions and enters the stomach. Just imagine, how difficult it would have been for you to chew and engulf the food in the absence of tongue?

Swallowing Food

Fig. 5: Swallowing Food

Tongue as an Organ of Speech

You produce different speech sounds as a stream of air coming from the lungs leaves body through mouth. Your mouth cavity is home to various organs of speech.

Different speech organs include tongue, teeth, lips, palate and uvula, etc. Here, tongue is of incredible importance. The tip of the tongue, the body and the back significantly contribute to the production of vowel and other sounds.

You can realize the true value of this major speech organ only when it is not there. Different parts of tongue play their own part in producing and modifying sounds. For example, labiodental sounds are produced while the tip of tongue touches the upper teeth.

To produce the /k/ and /g/ sounds, the back of the tongue raises against the roof top.

Composed of a set of extremely movable tongue muscles, it can quickly assume various shapes for the efficient performance of all the assigned tasks.

Tongue as an Organ of Speech

Fig. 6: Tongue As An Organ of Speech

Catching Prey

Did you ever see someone trying to catch a prey with their tongue? Probably, never. But certain animals, such as frogs, do. Frogs have an unusually long tongue adapted to catching insect pray.

Such animals also secrete a sticky substance. So, as an insect comes in contact with the moist, sticky tongue, it gets glued to it firmly. The frog then quickly retracts the tongue back into the mouth cavity to engulf it.

Catching Prey

Fig. 7: Catching Prey

Licking Fluids

Doesn’t it sound unethical to lick a plate after eating some sweet dish in it? Definitely, it does. But for animals, like cat and dog, it is a usual and socially accepted practice.

You do you feed a fluid, like milk, to the puppies and kittens? Usually, people put milk in a pot before such animals and they consume it by licking. It means tongue also serves as an organ for licking.

Licking Fluids

Fig. 8: Licking Fluids

An Organ for Sucking

Almost all the mammals suck milk from the breasts of their mother parent in infancy. Apart from mammals, there are various animals including insects which use sucking for feeding throughout their life.

Mosquitoes, flea, bedbug, ox pecker and vampire finch are some of the animals that feed on the blood of their victim through sucking. Leech, lamprey and vampire bat are some other animals that do sucking.

But how are they able to suck? They do so with the help of their tongue by creating negative pressure within their oral cavity.

An Organ for Sucking

Fig. 9: An Organ for Sucking

Use of Tongue for Grooming

Can you give example of an animal that uses tongue as an instrument for cleaning the body? Cat and some other animals do grooming and cleaning with the help of their tongue.

Such animals take out their tongue and rub it against feathery skin to remove any liquid and dirt particles. You might have seen cat doing so after licking milk.

Use of Tongue for Grooming

Fig. 10: Use of Tongue for Grooming

Indicator of Health

Among different tongue facts, it is interesting to note that appearance of tongue serves as an indicator of health. It takes time for the tongue to change its appearance. Therefore, the color of tongue at a particular time reflects the health of the individual.

For example, the appearance of a thicker white coat is the sign of predominance of cold in your body. It represents a weakness in some physiological function or a viral infection.

The individuals with thick, yellow coating on the tongue are likely to have some bacterial infection or inflammation.

What should be the color of the tongue to indicate perfect health? When the tongue color is pale-red, it means there is good circulation of blood in the body and you are enjoying a good health.

As the color changes to nearly white or extremely pale, there should be something rotten in the state of Denmark. And you should consult your healthcare provider to diagnose the disease you might be suffering from.

Human Tongue - Indicator of Health

Fig. 11: Indicator of Health


Human Tongue Diseases

The organ of taste is susceptible to various tongue conditions, including tongue infection, pain, tongue swelling and the tongue sores. Severe tongue diseases include cancer, ulcer, tongue blisters and hemangioma.

Different tongue problems are likely to cause changes in taste. In addition, there may occur changes in the color and texture of the tongue. Sometimes, the variations in the color and texture are also indicative of different diseases in other parts of the human body.

Tongue Cancer

Tongue cancer is the most serious disorder that affects the people over 40. The cancer forms in the squamous cells in the front two-thirds of your tongue (the oral tongue). Covering the surface of your tongue, the squamous cells are thin, flat cells. If malignancy appears in the back of your tongue (the base of the tongue), it would be a kind of neck or head cancer. [11] Tongue biopsy helps diagnose the type and stage of the tumor.

Tongue Cancer

Fig. 12: Tongue Cancer

Symptoms

  • Pain in the tongue or jaw that won’t go away.
  • Tongue white patch/es, occasionally spreading to gums, tonsils and lining of the mouth.
  • Chewing and swallowing cause pain.
  • Persistent mouth and tongue numbness. [12]
  • Bleeding from your tongue due to unexplained reasons.
  • Sore throat and development of lump inside the mouth cavity.

Causes

Tongue cancer is a type of mouth or oropharyngeal cancer. The exact causes of most head, neck and mouth cancer are not known. However, the medical researchers have listed some risk factors for tongue cancer. These risk factors include consumption of alcohol, smoking tobacco and transmission of HPV virus through sexual contact.

Treatment

It will be easy to control and cure cancer if you detect and diagnose it in the early stages of development. The suggestion of an effective treatment method for tongue cancer usually depends on its size and whether or not it has spread to other parts of mouth, like lymph nodes, tonsils and gums.

Surgery, radiotherapy and chemotherapy are the advanced treatments for tongue cancer. However, the tongue cancer treatment plan may also include target drug therapy. The aim of this therapy is to stop the cell growth of targeted cancerous cells.

Sometimes, targeted drug therapy is used in combination with radiation or chemotherapy or both.

Tongue Ulcer

The breakage or erosion of the surface of the tongue leads to the development of tongue ulcers. The open tongue sores, associated with tongue ulcers, can appear in other parts of the mouth as well. On the other hand, holes or breaks in the protective lining of the small intestine are called peptic ulcers. [13]

Fortunately, the tongue ulcers are not that much harmful. Nevertheless, they are still unpleasant at best and you need to take care of them.

Symptoms

The tongue ulcer symptoms are easily observable with the naked eye.

  • Appearance of round or oval sores on the surface of the tongue.
  • Sores may also appear on the gums, soft palate, lips or along the sides of tongue and cheek.
  • Experiencing tongue burn or a tingling sensation in the ulcerated area.
  • Food, toothbrush and braces may cause severe pain and irritation.
  • A bad or reduced sense of taste.

Causes

A number of different factors may lead to the appearance of painful tongue sores. Physical injury, allergies, chemical sensitivity, food sensitivities and bacterial or viral tongue infection are some of the common causes of mouth and tongue ulcers. Other tongue ulcer causes include tongue fungus and immune disorders.

Here it is pertinent to note that even minor injuries, such as over-eager brushing, biting your tongue, sporting accidents and dental works can ulcers.

Treatment

It isn’t that much difficult to get rid of tongue ulcers. The condition is rarely a cause for serious concern. However, if you leave it unaddressed, the ulcers are likely to become more dangerous.

You can cure the disorder by means of some natural remedies. For example, you can try using a saltwater or baking soda rinse to keep the would clean. Secondly, you can make a paste of salt, baking soda and milk of magnesia to soothe the area.

To ease swelling and inflammation, you can use mouthwash or rinse products that contain steroids. If the natural remedies for tongue ulcers do not work, you need to consult your healthcare provider for tongue ulcer treatment.

Tongue Glossitis

Tongue glossitis is a condition that refers to the loss of lingual papillae (depapillation) and smoothening and reddening of the surface of the organ. Glossitis is actually a type of geographic tongue. [14] In geographic tongue, the irregular patches on tongue give it a map-like appearance. [15]

Papillae, the small bumps on the surface of your tongue, contain thousands of tiny sensors or taste buds. They help you detect the taste of different types of foods you eat. When the lingual papillae disappear due to glossitis, you experience bad or reduced taste of the delicious things you eat. At the same time, you may also face difficulty in speaking, eating and swallowing. [16]

There are different types of glossitis, including acute, chronic, atrophic and idiopathic. In case of acute glossitis, the inflammation of tongue appears suddenly with severe symptoms. Inflammation of the tongue continues to recur in the chronic glossitis which may be the result of some other health condition.

When your tongue loses a large number of papillae with the change in its color and texture, you call the condition atrophic glossitis. It turns the organ dark red. The idiopathic or Hunter’s glossitis, on the other hand, affects the tongue muscles and also results in the loss of significant amount of papillae.

Symptoms

The tongue glossitis symptoms include:

  • Difficulty eating, speaking and swallowing food.
  • Feeling of tenderness and pain in the tongue.
  • Inflammation and change in color of your tongue.
  • Disappearance or loss of lingual papillae.
  • Smooth and reddened surface.
  • Blocked airway (rare).

Causes

The tongue glossitis causes include allergic reactions to food, chemicals or medicines. Bacteria, tongue virus or tongue yeast infection and injury from burns or bad-fitting dentures may lead to depapilllation and redness or tongue.

Alcohol consumption, tobacco, spices, certain vitamin deficiencies and hormonal factors may also contribute to the onset of the disease. Meanwhile, the skin conditions that affect the mouth may also cause glossitis.

Treatment

Effective home remedies are available for the tongue glossitis treatment. You can improve the health of your tongue, teeth and gums by flossing and brushing your teeth several times a day. In this way, you can not only relieve the symptoms of the condition but also prevent it from reoccurring.

If the home remedies do not work alone, you can go for a combination of medications and home care. The medications will help fight bacterial or other infections. Your doctor may prescribe the use of corticosteroids to reduce the soreness and redness.


Interesting Tongue Facts

  • Do you know the cats like tiger, lion, cheetah and house cat can’t taste sweets? It is because the cat’s sweet perception genes are broken. The pseudo or broken gene in cats makes them unable to detect sweet taste.
  • The tongue taste buds are specialized to detect five different types of tastes, namely, sweet, sour, salty, bitter and umami.
  • What is an umami taste? Can you also taste amino acids in food? Yeah, umami is the representation of the taste of amino acids.
  • Why does toothpaste affect the taste of certain foods? A tooth paste contains four main ingredients, viz. water, abrasives, fluoride and detergents (usually sodium lauryl sulfate or SLS). SLS suppresses sweet receptors.
  • Your tongue may contain 2,000 to 8,000 taste buds. Taste buds are small organs, embedded in the tongue epithelium that function in the perception of taste.
  • A muscular organ, your tongue does not contain a bone or cartilage and is capable of various muscular movements.
  • Your tongue is not just an organ of speech, it performs a variety of other important functions, including perception of taste, swallowing, licking, sucking and chewing, etc.
  • Some mammals, like cats, use their tongue for cleaning and grooming!
  • The animals, like frogs, have elongated tongue that is adapted to capturing insect prey.

References

  • The Free Dictionary, Tongue [1], Oropharynx [5]
  • Oxford Learners Dictionaries, Tongue [2]
  • Merriam Webster Dictionary, Tongue [3]
  • Encyclopedia Britannica, The Hyoid [4]
  • Medscape, Tongue Anatomy [6], [7], [9]
  • Sokoloff, A. J. (2004). Activity of tongue muscles during respiration: it takes a village? Journal of Applied Physiology, 96(2), 438-439. Retrieved. June 14, 2017 http://jap.physiology.org/content/96/2/438.short [8]
  • McComas, A. J. (1998). Oro-facial muscles: internal structure, function and ageing. Gerodongoloty 15(1), 3-14. Retrieved. June 14, 2017. http://onlinelibrary.wiley.com/doi/10.1111/j.1741-2358.1998.00003.x/full [10]
  • Cancer Treatment Centers of America, Tongue Cancer [11]
  • Cancer Research UK, About Tongue Cancer [12]
  • Doctors Health Press, Tongue Ulcers: Causes & Treatment [13]
  • Medline Plus, Glossitis [14], Geographic Tongue [15]
  • Healthline, Everything You Need to Know About Glossitis [16]
  • The Johns Hopkins Complete Guide to Symptoms and Remedies (2004), published by Black Dog & Leventhal Publishers, Inc.

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