The tongue is a powerful muscle

Sense organ

Did you know that the tongue is the strongest muscle in the human body proportional to size? Well, it is the large bundle of muscles on the floor of the mouth that manipulates food for chewing and swallowing. It is one of the organs of taste. Much of the surface of the tongue is covered with taste buds.

The tongue assists in forming the sounds of speech.

The tongue is made mainly of skeletal muscle and is attached to the hyoid bone, mandible and the styloid processes of the temporal bone. The muscles that attach the tongue are the extrinsic muscles of the tongue. Inside the tongue, there are four pairs of intrinsic muscles that can alter the shape of the tongue for talking and swallowing.

Since it contains no supporting skeletal structures for the muscles, the tongue is an example of a muscular hydrostat, like an octopus arm.

The dorsum (top side) of the tongue can be divided into two parts, a pharyngeal part (posterior third of the tongue), which faces backward to the oropharynx, and an oral part (anterior two-thirds of the tongue) that lies mostly in the mouth. The two parts are separated by a V-shaped groove, which marks the sulcus terminals (or terminal sulcus).

Papillae and taste buds

The oral part of the tongue is covered with small bumpy projections called papillae. There are four types of papillae: filiform (thread-shape), fungiform (mushroom-shape), foliate (leaf-shape), and circumvallate (ringed-circle). All papillae except the filiform have taste buds on their surface.

The circumvallate are the largest of the papillae. There are 8 to 14 circumvallate papillae arranged in a V-shape in front of the sulcus terminals, creating a border between the oral and pharyngeal parts of the tongue.

There are no lingual papillae on the underside of the tongue. It is covered with a smooth mucous membrane, with a fold (the lingual frenulum) in the centre.

The upper side of the posterior tongue (pharyngeal part) has no visible taste buds, but it is bumpy because of the lymphatic nodules lying underneath. These follicles are known as the lingual tonsil. Intrinsic muscles of the tongue

Four pairs of muscles originate within the tongue, and run in parallel down its length.

* The superior longitudinal muscle runs along the superior surface of the tongue under the mucous membrane, and elevates, assists in retraction of, or deviates the tip of the tongue. It originates near the epiglottis, the hyoid bone, from the median fibrous septum; and is controlled by the XII hypoglossal nerve.

* The inferior longitudinal muscle lines the sides of the tongue, and is joined to the styloglossus muscle.

* The verticalis muscle is located in the middle of the tongue, and joins the superior and inferior longitudinal muscles.

The transverses muscle divides the tongue at the middle, and is attached to the mucous membranes that run along the sides.

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Interesting facts

* Stephen Taylor holds the record for the world's longest tongue. It measures 9.4 centimetres from the tip to the centre of his closed top lip. Annika Irmler holds the record for the longest female tongue, at 7 centimetres.

* We have four basic tastes. The salt and sweet taste buds are at the tip of the tongue, bitter at the base, and sour along the sides.

* Unless food is mixed with saliva, you cannot taste it.

* Not all our taste buds are on our tongue; about 10 per cent are on the palette and the cheeks.

* Every person has a unique tongue print, like the fingerprints.