Components of the Tongue and Their Functions
Tip of the Tongue
The anterior portion of the tongue is referred to as the tip of the tongue (Tip of Tongue), known for its high mobility. Its upper surface has a rough texture and houses taste buds along with lingual papillae, while its underside is smooth.
Body of the Tongue
The body of the tongue (Body of Tongue) contains numerous papillae featuring taste buds as well as serous glands that secrete saliva, essential for moistening the oral cavity and aiding in food lubrication.
Base of the Tongue
The posterior segment of the tongue is known as the base of the tongue (Base of Tongue), which includes a collection of lymphatic tissues called lingual tonsils, along with both serous and mucous glands.
Inferior Surface of the Tongue
The inferior surface of the tongue (Inferior of Tongue) extends to the floor of the mouth, characterized by its purplish hue and smooth mucosal membrane, devoid of papillae, and rich in blood vessels.
Root of the Tongue
The root of the tongue (Root of Tongue) represents the remaining part of the underside of the tongue, situated on the mouth’s floor, housing bundles of nerves, arteries, and muscles that branch out to various tongue regions.
Muscles of the Tongue
The tongue comprises a network of intertwined muscles that facilitate its movement, primarily made up of the tongue itself. The muscles can be categorized as follows:
- Intrinsic Muscles: These muscles exist entirely within the tongue and are responsible for its shape. They include:
- Superior Longitudinal Muscle: Elevates the tip and sides of the tongue while shortening its length.
- Inferior Longitudinal Muscle: Lower the tip and sides of the tongue while also shortening it.
- Transverse Muscle: Narrows, elongates, raises, and extends the tongue.
- Vertical Muscle: Flattens and widens the tongue inside the mouth, also assisting in its protrusion.
- Extrinsic Muscles: These muscles exist outside the tongue, connecting it to surrounding bones and controlling its positioning. They include:
- Genioglossus: Moves the tongue downward, pulls it forward, and enables back-and-forth movement.
- Hyoglossus: Lowers the tongue and draws it back toward the mouth.
- Styloglossus: Assists in moving the tongue for swallowing food.
- Palatoglossus: Elevates the back part of the tongue.
Nerves of the Tongue
The nerves associated with the tongue (Nerve of Tongue) include:
- Hypoglossal Nerve: Also known as cranial nerve XII, this primary nerve controls all tongue muscles except for the palatoglossus, located below the angle of the mandible.
- Lingual Nerve: A branch of the trigeminal nerve, it aids in the general sensation of the anterior two-thirds of the tongue, located beneath the mandible.
- Tympanic Nerve: A branch from the facial nerve responsible for taste sensation.
- Glossopharyngeal Nerve: Known as cranial nerve IX, it helps with general sensation of the posterior third of the tongue, situated near the styloglossus and hyoglossus muscles.
- Internal Laryngeal Nerve: Branching from the vagus nerve, it provides sensation to a small area of the tongue, located anterior to the epiglottis.
Papillae of the Tongue
The papillae of the tongue (Papillae of Tongue) present on its surface include four types:
- Filiform Papillae: These conical-shaped papillae are covered with keratinized squamous epithelium and contribute to the tongue’s rough texture. They are the most numerous type and facilitate food friction during swallowing but do not contain taste buds.
- Fungiform Papillae: Less abundant than filiform papillae, they are scattered across the dorsal surface of the tongue and contain numerous blood vessels with a limited number of taste buds.
- Foliate Papillae: These appear as long, parallel folds on the posterior side of the tongue and are rich in taste buds.
- Circumvallate (Vallate) Papillae: Arranged in a linear fashion, they form a group of 8-12 papillae, recognizable by their longitudinal section containing grooves that drain serous salivary glands to stimulate taste buds.
Taste Buds
Taste buds (Taste Buds) are crucial for the sensation of taste, as they contain taste receptor cells grouped together and located on the surface of the tongue.
Blood Vessels of the Tongue
The blood vessels of the tongue (Blood Vessels of Tongue) branch from the lingual arteries, originating from the external carotid artery. Venous drainage occurs through the dorsal lingual vein and deep lingual veins, which converge into the internal jugular vein, ensuring adequate blood supply throughout the tongue.
The tongue comprises several distinct parts beginning from its tip, through the body, base, inferior surface, and root, along with intricate components such as the interwoven muscles, categorized into intrinsic and extrinsic muscles, as well as the nerve network distributing throughout the tongue, assorted papillae that contain taste buds, and vascular structures.
The Role of the Tongue in Taste
The tongue hosts taste buds that enable humans to perceive the five basic tastes: sweet, bitter, sour, salty, and umami (associated with glutamate). All regions of the tongue can sense different flavors, contrary to the common belief that specific areas correspond to individual tastes, often referred to as the “taste map.” The nerves throughout the tongue facilitate the transmission of taste signals to the brain, where they are interpreted.
General Information About the Tongue
Here are some general facts about the tongue:
- The average length of an adult male’s tongue is approximately 8.5 cm, while that of an adult female averages 7.9 cm.
- An adult human tongue contains between 2000 and 4000 taste buds.
- The tongue consists of eight interwoven muscles, debunking the myth that the tongue is the strongest muscle in the human body.
- The tongue’s muscles are unique in that they operate independently of the skeletal system.
- The tongue has a high fat content, which increases with body weight.
Despite its small size, the tongue is composed of multiple parts that function synergistically to enhance its roles in eating, tasting, speaking, and swallowing. Its vital and complex components, such as the nerves and muscles, operate independently from the human skeletal framework.