Detail study of tongue 

Tongue

The floor of mouth cavity is a large, muscular, glandular, sensory tongue which is other wisely known as lingua or glossa.

It helps in injection, mastication, tasting, swallowing and speech.

It contains different types of papillae which can sense the taste, texture and temperature of the food perfectly.

There is a fold of mucus membrane under surface of tongue.

The upper surface & the lateral surface of tongue is covered by different papillae.

Papillae

The tongue is covered with numerous membrane at its upper and lateral surface.

It may contain receptor for gustation which contain taste buds or receptor for touch which increases fraction between tongue and food or may contain some lingual glands which secrete mucus and watery fluid which contain lingual lipase.

4 Types of papillae

There are several types of papillae on the basis of their structure and function.

Circumvallate papillae -

There are 12 large Circumvallate papillae present at the back of tongue forming an inverted v shape tongue.

These papillae contain 100-300 taste buds.

Fungiform papillae

These are mushroom shaped papillae present on entire surface of tongue.

They contain about 5 taste buds.

Filiform papillae

These are present on the entire surface of the tongue.

These are pointed papillae containing tactile receptor but no taste buds.

They increase friction between tongue and food and provide rough surface to tongue.

These are highly developed in carnivorous animals.

Foliate papillae

These are located on the lateral margin of tongue.

They are leave shaped papillae.

Taste buds of these papillae degenerate in early childhood.

Taste bud-

The taste buds are oval structure consisting of gustatory receptor cells or taste cells with supporting cells.

These taste buds has gustatory hair at its upper surface and the basal surface is connected to the papillae through sensory neurons.

The taste buds are the taste receptor.

Taste types-

Taste or gustation is a chemical sense.

There are 5 types of primary tastes.

These are sweet, sour, salty, bitter and umami.

Flavors are the combination of one or more primary taste with definite food temperature, texture and aroma.

Nerve supply to tongue -

1. Facial nerves -

Supplies anterior two third of tongue. It carries the sensation of gustation.

2. Glossopharyngeal nerves-

Supplies posterior one third of tongue. It also carries the sensation of gustation.

3. Trigeminal nerves-

Carries sensation of pain, pressure and temperature in tongue.

4. Vagus nerves-

Supplies back of tongue. Carries sensation of gustation.

5. Hypoglossal nerves-

Supply muscles of tongue and its movement.

Tongue of other animals

1. Tongue of chameleons

Chameleons use their tongue for hunting their prey. They have ultra-sticky saliva on their tongue which stick on its prey and pulls it toward its mouth. The tongue of chameleon is almost twice the length of its body.

2. Tongue of tiger

Tigers use their sharp papillae to strip the flesh of the prey's body. Their tongue can easily remove skin & feather.

3. Tongue of humming birds

The tongue of hummingbirds modified to help them to slurp the nector from deep inside the flower.

4. Tongue of snakes

The tongue of snakes is modified to sense scent particles in the air.