The Tongue

Tongue is a muscular structure that has the organs of taste

reception. The organs for sense of taste are the taste buds. Tongue is located inside the mouth and is an important

muscle. It does not have any bones. It is reddish-pink in color. The main function of

tongue is taste, help in chewing food, in swallowing food and

speech.

Human Tongue

Papillae Papillae contains taste bud (chemo-receptors), which helps us identify between different tastes of food.

When we chew food, a portion of it dissolves in the saliva. This

dissolved part of food comes in contact with the taste buds and generates nerve impulses. These

nerve fibres are known as microvilli. These nerve fibres carry messages to the taste center in the

brain. Then brain perceives the taste.

Four Types Of Papillae

-Foliate, Vallate and Fungiform have taste buds which helps in identifying the taste-Filiform helps in holding the food ( to grip the food in place)

The main function of tonsils is to serve as the first line of defense in the immune system.

Tonsils AdenoidsThey help in fighting infections

Types of Tonsils1. The palatine tonsils or simply referred to as 'the tonsil'- inbetween the anterior & posterior pillars of oropharynx2. The Nasopharyngeal tonsils or the adenoids- in the nasopharynx3. The tubal tonsils- near opening of eustachian tubes.4. The Lingual tonsils- in the base of the tongue.5. Tonsillar patches in posterior pharyngeal wall.

Frenulum linguae: It secures or holds the tongue in place inside the mouth.

Very small fibre-like or hair-like projections are present on the upper side of the tongue which connect with nerve fibres at the lower end of the tongue which lead to the brain.

Taste Buds-Are structures located on the

surface of the tongue. They are embedded in the mucosa of the papillae of the tongue. The papillae are projections on the upper surface of the tongue.

-Taste buds contain the receptors for taste

Structure of Taste Buds

There are about 3000 taste buds on the tongue of an adult person.

There are four main tastes - sweet, salty, sour and bitter. These four main tastes are felt by different portion of the tongue. The tip of

our tongue senses salt and sweet. The taste buds at the sides detect sour taste. The rear portion of the

tongue detect bitter taste.

Four Main Taste

Taste receptor cells or gustatory receptors

They are spindle-shaped cells that are neurosensory. They have

hairs on their free ends and on the other end, they have nerve

fibres. They number 5-15 in each taste bud

Supporting cells

They are columnar cells, numbering about 40 found

between the taste receptor cells, supporting them.

Human Tongue Diseases

Oral CandidiasisCandidiasis is a fungal infection,

which is mostly caused a yeast called Candida albicans. Other less common causative agents

are Candida glabrata and Candida tropicalis. When it occurs on the mucous membrane of the mouth,

it is known as oral candidiasis.The identifying

symptoms are appearance of thick white or cream-colored

deposits on the surface of tongue.

The infected tongue may appear red and a bit raised from the normal level. Oral candidiasis

causes a burning sensation and a lot of discomfort. It is treated

with antifungal drugs. The patient is asked to use this oral suspension to wash around the

mouth and swallow. In some severe cases, the medicine may

be administered intravenously on the tongue.

LeukoplakiaLeukoplakia is a disease the involves the formation of a white spot or patch

on the mucous membrane in the mouth. The common mouth parts that develop leukoplakia are tongue, gums, etc. If not treated on time, leukoplakia

may lead to cancer. The leukoplakia patches on tongue cannot be easily

scraped off. The common causes of it are smoking and chewing tobacco. In

majority of the cases, this tongue disease is harmless. But seeking dental assistance is necessary to

prevent cancer.

Keratosis PharyngisIt occurs when the protein of the

hair or nails, called keratin, grows at the pharynx. This is a

tongue disease which belongs to a group of those disease for which there is no treatment

known till date. The identifying symptoms are pain at the back of

the throat and difficulty in swallowing.

Quiz time

1.) A muscular structure that has the organs of taste reception.

2.) Its contains taste buds which helps us identify between different tastes

of food.

3-6.) Give the four types of Papillae

7.) Serve as the first line of defense in the immune system.

8.) Contain the receptors for taste

9.) It secures or holds the tongue in place inside the mouth.

10.) They are spindle-shaped cells that are neurosensory.