Tongue is a movable, flexible organ with muscles found on the floor of the mouth of most vertebrates. It is the major organ of taste and manipulates food for chewing and swallowing as part of the digestive process. It is coated by mucosa, a wet, pink tissue. It takes part in licking, tasting, breathing, swallowing, and speaking. The rough texture of the tongue is due to the presence of papillae. It is covered by a variety of taste buds. The tongue has many nerves that aid in the transmission of taste information to the brain and hence aid in taste sensation. Old English ‘tunge’, which descended from Proto-Germanic ‘tungōn’, is where the word tongue first appeared.
What is Tongue?
One of the main muscle organs in the oral cavity is the tongue. There are numerous lingual papillae that contain the taste buds that cover the tongue’s dorsum, or upper surface. It has many nerves and blood vessels and is sensitive. Saliva also keeps it moist. The natural tooth-cleaning process is assisted by the tongue. Speech production in humans and animal vocalization in other species are both major functions of the tongue.
Anatomy of Tongue
The tongue is a pinkish muscular organ present within the oral cavity of the mouth.
Location of Tongue
The tongue extends from the hyoid bone in the center of the neck to the floor of the mouth.
Parts of Tongue
The average tongue length of a man is 3.3 inches, compared to 3.1 inches for a woman. The average length of the tongue is about 10 cm, though there is a lot of individual variation in this measurement. There are three main parts:
- Tip: The front-most and most movable portion of the tongue is its tip or apex.
- Body: The body of the tongue comes next. It has a smooth ventral (inferior) surface that is connected to the floor of the oral cavity by the lingual frenulum, and a rough dorsal (superior) surface that abuts the palate and is covered in taste buds and lingual papillae.
- Base: The most posterior portion of the tongue is its base. It is covered with foliate papillae along the posterolateral surface and many lymphoid aggregates known as the lingual tonsils.
Papillae
Four different types of papillae exist in humans:
- Filiform: Filiform papillae, which are found in the front two-thirds of the tongue, have the appearance of threads. Filiform papillae are distinct from other papillae types in that they lack taste receptors.
- Fungiform: The mushroom-like form of these papillae gives them their name. Fungiform papillae, which are largely on the sides and tip of the tongue, contain about 1,600 taste buds.
- Circumvallate: The circumvallate papillae are the little bumps on the back of the tongue. They resemble the other kinds of papillae but are bigger and have about 250 taste buds.
- Foliate: The foliate papillae, which are found on either side of the back of the tongue, resemble rough tissue folds. There are roughly 20 foliate papillae on each person, and each one houses several hundred taste buds.
Taste Buds
There are five different gustatory sensations that people can experience. These taste umami, sweet, salty, sour, and bitter. The taste cells’ apical surface is home to microvilli that have a variety of receptors that can bind to different substances.
Structure of Tongue
The tongue is embryologically separated into an anterior and a posterior half. The oral or pre-sulcal section of the tongue is another name for its anterior region. The pharyngeal or postsulcal section of the tongue, on the other hand, is the term used to describe the back of the tongue. The lingual septum, a vertical stretch of fibrous tissue that results in a groove on the surface of the tongue called the median sulcus, divides the tongue’s left and right sides for the majority of its length. The following components make up the tongue:
Epithelium
The epithelium includes taste buds and papillae. The taste buds aid in flavor perception. They have a wide bottom and are lined with squamous epithelial tissue. The taste cells have a nucleus in the middle and are thin, rod-shaped cells. Short-taste hairs are present on the free surface. Taste is detected by taste cells and is properly perceived when it dissolves in saliva.
Muscles
There are two categories for the eight tongue muscles: intrinsic and extrinsic.
- Extrinsic Muscles: The four extrinsic muscles stretch to the tongue from their osseous origins. They are genioglossus, hyoglossus, styloglossus, and palatoglossus. Their primary purposes involve moving the tongue’s position to protrude, retract, and move from side to side.
- Intrinsic Muscles: Along the length of the tongue, four pairs of intrinsic muscles have their origins and inserts there. They are the transverse muscle, the vertical muscle, the inferior longitudinal muscle, and the superior longitudinal muscle. This gives shape and makes it easier to speak, swallow, and eat.
Nerve Supply
The chorda tympanic branch of the facial nerve and the glossopharyngeal nerve are both involved in taste perception. The trigeminal nerve carries pain, touch, and temperature perceptions.
Blood Supply
The lingual artery, a branch of the external carotid artery, supplies the tongue with the majority of its blood flow. Drainage from the lingual veins is sent to the internal jugular vein. The bottom of the mouth is also supplied with blood by the lingual artery. Additional blood is sent to the tongue’s root by the ascending pharyngeal artery and the tonsillar branch of the facial artery.
Salivary Glands
The tongue is made up of a few tiny, dispersed glands. They come in three different varieties:
- Sublingual Glands: The tongue has glands called sublingual glands. Hundreds of tiny glands are also present. These glands produce saliva (spit), which they then release through duct-like apertures into the mouth. Food becomes moist due to saliva, which facilitates chewing, swallowing, and food digestion.
- Submaxillary Gland: It begins with Wharton’s duct, which is located on the sides of the tongue’s frenulum, on the floor of the mouth.
- Mucous and Serous Glands: The mucous gland secretes a firm, viscous secretion that contains mucin, which is mostly engaged in lubrication, while the serous gland secretes a thin, watery secretion that contains zymogens, antibodies, and inorganic ions that are principally involved in digestion and defense.
- Lymph Nodes: The submental nodes get drainage from the tongue’s tip. The posterior one-third of the tongue drains to the jugulo-omohyoid nodes, while the left and right half of the anterior two-thirds of the tongue drain to submandibular lymph nodes.
Functions of Tongue
Functions of the tongue include:
- Taste: On its dorsal surface, the tongue has several taste buds, each of which has taste receptor cells that can detect a specific class of flavors.
- Mastication: The tongue plays a significant supporting role in the digestive system. The tongue is utilized for mastication, or crushing food on the hard palate, and for manipulating food to soften it before swallowing.
- Speech: The extrinsic muscles that move the tongue and the intrinsic muscles that alter its form make the tongue one of the main articulators in the creation of speech.
- Deglutition: Swallowing, also known as deglutition in medical settings, is the physiological process in which food or other liquids move from the mouth down the pharynx and esophagus while the epiglottis is closed.
- Secretion: The tongue has glands called sublingual glands. Hundreds of tiny glands are also present. These glands produce saliva (spit), which they then release through duct-like apertures into the mouth. Food becomes moist due to saliva, which facilitates chewing, swallowing, and food digestion.
FAQs on Tongue
Q: What is the tongue?
Answer:
The tongue is a movable, flexible organ with muscles found on the floor of the mouth of most vertebrates. It is the major organ of taste and manipulates food for chewing and swallowing as part of the digestive process.
Q: Where are foliate papillae found?
Answer:
The foliate papillae are found on either side of the back of the tongue which resemble rough tissue folds. There are roughly 20 foliate papillae on each person, and each one houses several hundred taste buds.
Q: Define the term Deglutition.
Answer:
Swallowing, also known as deglutition in medical settings, is the physiological process in which food or other liquids move from the mouth down the pharynx and esophagus while the epiglottis is closed.
Q: Name the intrinsic muscles of the tongue.
Answer:
They are the transverse muscle, the vertical muscle, the inferior longitudinal muscle, and the superior longitudinal muscle.