Structure of Tongue

Human Tongue Structure

The tongue is a primary muscular organ in the oral cavity. It is covered with a moist, pink tissue called the mucosa. There are tiny bumps which are called papillae which gives the tongue its rough texture. Several thousand taste buds are located on the surface of the papillae which are collections of nerve-like cells that connect to nerves running to the brain.

The tongue is anchored to the mouth by webs of tissue and mucosa and they tether holding down the front of the tongue which is known as the frenum. At the back of the mouth, the tongue is anchored to the hyoid bone. 

The tongue is the vital organ for the taste of food, chewing, swallowing and speech. In this topic, we will discuss the structure of the tongue and its functions.

Tongue Structure and Function

The organ is a mass of muscle which is almost completely covered by the mucosa membrane. It occupies the oral cavity and oropharynx. It is divided into two parts. 

  1. The oral or presulcal part or the anterior part

  2. The pharyngeal or the postsulcal part or the posterior part

Parts of the Tongue

The tongue is approximately 10 cms long and can be divided into 

  • The tip or apex, the most mobile part of the tongue.

  • The body, which has a rough dorsal surface and is populated with taste buds and lingual papillae and a smooth ventral surface which is attached to the floor of the oral cavity.

  • The base, which is the posterior part of the tongue.

The sublingual salivary glands and vascular bundles are located below the mucosa of the oral cavity floor. Posterior to the base of the tongue is the dorsal surface of the epiglottis and laryngeal inlet, and the posterior wall of the oropharynx.

Anterior Two Thirds

The anterior part of the tongue includes the apex and body of the organ and it ends at the sulcus terminalis; this part extends laterally in an oblique direction from the foramen cecum towards the palatoglossal arch. The mucosa layer of the dorsal surface is made of 

  • Circumvallate papillae.

  • Filiform papillae.

  • Fungiform papillae.

A longitudinal midline groove runs in an anteroposterior direction from the tip to the foramen cecum of the tongue.  It also represents the median lingual septum of the organ and the inserts in the hyoid bone.

The foliate papillae on the lateral surface of the tongue are arranged in a series of vertical folds. Coming to the ventral mucosa, it is smooth and continuous with the mucosa of the floor. The lingual veins are superficial and are observed on either side of the lingual frenulum. Lateral to the lingual veins are pleated folds of mucosa called plica fimbriata. They are angled anteromedially towards the apex of the tongue.

Posterior Third

The posterior third part of the organ is made up of the base of the organ. It is located behind the palatoglossal folds and functions as the anterior wall of the oropharynx. This part does not have any lingual papillae and the mucosa is populated by lymphatic tissue known as lingual tonsils. The mucosa is also continuous with the mucosa of the lateral palatine tonsils, the lateral oropharyngeal walls, and the glossoepiglottic and epiglottis folds.

Structure of Taste Buds

The taste buds are sensory taste receptors located on the tongue, throat and palate, they help form the perception of taste. Taste buds or taste receptor cells detect chemicals dissolved in saliva from food and other objects and then send their sensory information through neurons to the gustatory centre of the brain. 

Taste receptor cells interact with incoming chemicals from food and other objects on the tongue in groups of 50–150. Each group forms a taste bud, which is grouped together with other taste buds into taste papillae.

The taste buds are embedded in the epithelium of the tongue and they make contact with the outside environment through a taste pore. Microvilli-like structures extend from the outer ends of the taste buds through the taste pore, where the processes are covered by mucus that lines the oral cavity. 

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FAQ (Frequently Asked Questions)

1. Is the tongue an organ or a muscle?

The tongue is a mass muscle and is one of the major organs of the human body. It is divided into two parts which are the anterior and posterior and these consist of various glands and muscles. Moreover, there are thousands of taste buds spread across the surface of the tongue which helps us detect taste from the food which makes it the primary organ of taste in the gustatory system.  It also has primary roles in speech, chewing and swallowing of food and because of saliva, it also partially digests the food.

2. What are the salivary glands present in the human body?

There are three salivary glands present in the human body

  1. Parotid glands: Located opposite to the second upper molar tooth its secreted serous saliva which assists in mastication and swallowing of food.

  2. Submaxillary glands: They are also called the submandibular glands and are located alongside the lower jawbone. They also secreted serous saliva.

  3. Sublingual glands: These glands are located beneath the mucous membrane of the floor of the oral cavity, near the chin region. These glands secrete a mixed fluid which consists mainly of mucus.