Tongue
Tongue | |
---|---|
tonsillar branch, ascending pharyngeal | |
Vein | lingual |
Nerve | Sensory Anterior two-thirds: Lingual (sensation) and chorda tympani (taste) Posterior one-third: Glossopharyngeal (IX) Motor Hypoglossal (XII), except palatoglossus muscle supplied by the pharyngeal plexus via vagus (X) |
Lymph | Deep cervical, submandibular, submental |
Identifiers | |
Latin | lingua |
MeSH | D014059 |
TA98 | A05.1.04.001 |
TA2 | 2820 |
FMA | 54640 |
Anatomical terminology] |
The tongue is a
The human tongue is divided into two parts, an
There are two groups of muscles of the tongue. The four intrinsic muscles alter the shape of the tongue and are not attached to bone. The four paired extrinsic muscles change the position of the tongue and are anchored to bone.
Etymology
The word tongue derives from the
In humans
Structure
The tongue is a
The anterior tongue is, at its apex, thin and narrow. It is directed forward against the lingual surfaces of the lower
The average length of the human tongue from the
In phonetics and phonology, a distinction is made between the tip of the tongue and the blade (the portion just behind the tip). Sounds made with the tongue tip are said to be apical, while those made with the tongue blade are said to be laminal.
Upper surface
The upper surface of the tongue is called the dorsum, and is divided by a groove into symmetrical halves by the median sulcus. The foramen cecum marks the end of this division (at about 2.5 cm from the root of the tongue) and the beginning of the terminal sulcus. The foramen cecum is also the point of attachment of the
The terminal sulcus is a shallow groove that runs forward as a shallow groove in a V shape from the foramen cecum, forwards and outwards to the margins (borders) of the tongue. The terminal sulcus divides the tongue into a posterior pharyngeal part and an anterior oral part. The pharyngeal part is supplied by the glossopharyngeal nerve and the oral part is supplied by the lingual nerve (a branch of the mandibular branch (V3) of the trigeminal nerve) for somatosensory perception and by the chorda tympani (a branch of the facial nerve) for taste perception.
Both parts of the tongue develop from different pharyngeal arches.
Undersurface
On the undersurface of the tongue is a fold of mucous membrane called the
Muscles
The eight muscles of the human tongue are classified as either intrinsic or extrinsic. The four intrinsic muscles act to change the shape of the tongue, and are not attached to any bone. The four extrinsic muscles act to change the position of the tongue, and are anchored to bone.
Extrinsic
The four extrinsic muscles originate from bone and extend to the tongue. They are the
The genioglossus arises from the mandible and protrudes the tongue. It is also known as the tongue's "safety muscle" since it is the only muscle that propels the tongue forward.
The hyoglossus, arises from the hyoid bone and retracts and depresses the tongue. The chondroglossus is often included with this muscle.
The styloglossus arises from the styloid process of the temporal bone and draws the sides of the tongue up to create a trough for swallowing.
The palatoglossus arises from the palatine aponeurosis, and depresses the soft palate, moves the palatoglossal fold towards the midline, and elevates the back of the tongue during swallowing.
Intrinsic
Four paired intrinsic muscles of the tongue originate and insert within the tongue, running along its length. They are the
The superior longitudinal muscle runs along the upper surface of the tongue under the mucous membrane, and functions to shorten and curl the tongue upward. It originates near the epiglottis, at the hyoid bone, from the median fibrous septum.
The inferior longitudinal muscle lines the sides of the tongue, and is joined to the styloglossus muscle. It functions to shorten and curl the tongue downward.
The vertical muscle is located in the middle of the tongue, and joins the superior and inferior longitudinal muscles. It functions to flatten the tongue.
The transverse muscle divides the tongue at the middle, and is attached to the mucous membranes that run along the sides. It functions to lengthen and narrow the tongue.
Blood supply
The tongue receives its
An area in the neck sometimes called the
Nerve supply
Innervation of the tongue consists of motor fibers,
- Motor supply for all intrinsic and extrinsic muscles of the tongue is supplied by palatoglossus, which is innervated by the vagus nerve (CN X).[6]
Innervation of taste and sensation is different for the anterior and posterior part of the tongue because they are derived from different embryological structures (pharyngeal arch 1 and pharyngeal arches 3 and 4, respectively).[9]
- Anterior two-thirds of tongue (anterior to the vallate papillae):
- Taste: chorda tympani branch of the special visceral afferentfibers
- Sensation: lingual branch of the mandibular (V3) division of the general visceral afferentfibers
- Taste: chorda tympani branch of the
- Posterior one third of tongue:
- Taste and sensation: glossopharyngeal nerve (CN IX) via a mixture of special and general visceral afferent fibers
- Base of tongue
- Taste and sensation: internal branch of the superior laryngeal nerve (itself a branch of the vagus nerve, CN X)
Lymphatic drainage
The tip of tongue drains to the submental nodes. The left and right halves of the anterior two-thirds of the tongue drains to submandibular lymph nodes, while the posterior one-third of the tongue drains to the jugulo-omohyoid nodes.
Microanatomy
The upper surface of the tongue is covered in
The tongue can divide itself in dorsal and ventral surface. The dorsal surface is a stratified squamous keratinized epithelium, which is characterized by numerous mucosal projections called papillae.[11] The lingual papillae covers the dorsal side of the tongue towards the front of the terminal groove. The ventral surface is stratified squamous non-keratinized epithelium which is smooth.[12]
Development
The tongue begins to develop in the fourth week of
In the fifth week a pair of lateral lingual swellings, one on the right side and one on the left, form on the first pharyngeal arch. These lingual swellings quickly expand and cover the median tongue bud. They form the anterior part of the tongue that makes up two-thirds of the length of the tongue, and continue to develop through prenatal development. The line of their fusion is marked by the median sulcus.[13]
In the fourth week, a swelling appears from the second pharyngeal arch, in the midline, called the copula. During the fifth and sixth weeks, the copula is overgrown by a swelling from the third and fourth arches (mainly from the third arch) called the hypopharyngeal eminence, and this develops into the posterior part of the tongue (the other third and the posterior most part of the tongue is developed from the fourth pharyngeal arch). The hypopharyngeal eminence develops mainly by the growth of endoderm from the third pharyngeal arch. The boundary between the two parts of the tongue, the anterior from the first arch and the posterior from the third arch is marked by the terminal sulcus.[13] The terminal sulcus is shaped like a V with the tip of the V situated posteriorly. At the tip of the terminal sulcus is the foramen cecum, which is the point of attachment of the thyroglossal duct where the embryonic thyroid begins to descend.[6]
Function
Taste
Chemicals that stimulate
The tongue is equipped with many
Mastication
The tongue is an important accessory organ in the digestive system. The tongue is used for crushing food against the hard palate, during mastication and manipulation of food for softening prior to swallowing. The epithelium on the tongue's upper, or dorsal surface is keratinised. Consequently, the tongue can grind against the hard palate without being itself damaged or irritated.[18]
Speech
The tongue is one of the primary articulators in the production of
Intimacy
The tongue plays a role in physical intimacy and sexuality. The tongue is part of the erogenous zone of the mouth and can be used in intimate contact, as in the French kiss and in oral sex.
Clinical significance
Disease
A
The tongue is prone to several
There are several types of
Food debris, desquamated epithelial cells and bacteria often form a visible tongue coating.[21] This coating has been identified as a major factor contributing to bad breath (halitosis),[21] which can be managed by using a tongue cleaner.
Medication delivery
The
Other animals
The muscles of the tongue evolved in
Some animals have tongues that are specially adapted for catching prey. For example, chameleons, frogs, pangolins and anteaters have prehensile tongues.
Other animals may have organs that are
Society and culture
Figures of speech
The tongue can serve as a
A common temporary failure in word
Gestures
Sticking one's tongue out at someone is considered a childish gesture of
Body art
Tongue piercing and splitting have become more common in western countries in recent decades.[when?] One study found that one-fifth of young adults in Israel had at least one type of oral piercing, most commonly the tongue.[31]
Representational art
Protruding tongues appear in the art of several Polynesian cultures.[32]
As food
This section needs additional citations for verification. (October 2022) |
The tongues of some animals are consumed and sometimes prized as delicacies. Hot-tongue sandwiches frequently appear on menus in
Tongues of seals and whales have been eaten, sometimes in large quantities, by sealers and whalers, and in various times and places have been sold for food on shore.[33][page needed]
Gallery
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Human tongue
-
Spots on the tongue
See also
Further reading
- Pennisi, Elizabeth (May 26, 2023). "How the tongue shaped life on Earth". Science. 380 (6647). American Association for the Advancement of Science: 786–791. . Retrieved 25 June 2023.
References
This article incorporates text in the public domain from page 1125 of the 20th edition of Gray's Anatomy (1918)
- ^ hednk-024—Embryo Images at University of North Carolina
- ISBN 0-13-981176-1.
- ^ a b "Tongue". Online Etymology Dictionary. Retrieved 17 September 2017.
- ISBN 0-02-864558-8.
- . Retrieved 30 August 2023.
- ^ ISBN 978-0-8089-2306-0.
- ^ "Pirogov's triangle". Whonamedit? - A dictionary of medical eponyms. Ole Daniel Enersen.
- PMID 13010300.
- ISBN 978-1451190380.
- ^ Bernays, Elizabeth; Chapman, Reginald. "taste bud anatomy". Encyclopædia Britannica.
- ^ Fiore, Mariano; Eroschenko, Victor (2000). Di Fiore's atlas of histology with functional correlations (PDF). Lippincott Williams & Wilkins. p. 238. Archived from the original (PDF) on 21 June 2017.
- ISBN 950-02-0386-3.
- ^ ISBN 0-443-06583-7.
- ISBN 978-0470084717.
- ISBN 978-0321559807.
- ISBN 9780716752158.
- ^ O'Connor, Anahad (November 10, 2008). "The Claim: The tongue is mapped into four areas of taste". The New York Times. Retrieved June 24, 2011.
- ISBN 978-0199234462.
the tongue is also responsible for the shaping of the bolus as food passes from the mouth to the rest of the alimentary canal
- ^ "Oral Cancer Facts". The Oral Cancer Foundation. 28 August 2017. Archived from the original on 22 June 2013. Retrieved 17 September 2017.
- PMID 16669472.
- ^ ISBN 978-1-4377-0416-7.
- PMID 12171472.
- ^ "A Dog's Tongue". DrDog.com. Dr. Dog Animal Health Care Division of BioChemics. 2014. Archived from the original on 2010-09-20. Retrieved 2007-03-09.
- S2CID 23295086.
- ISBN 0-412-61390-5.
- ISBN 0-03-910284-X.
- ISBN 1-112-23645-7.
- til (тіл)
- ^ Dresser, Norine (8 November 1997). "On Sticking Out Your Tongue". Los Angeles Times. Retrieved 18 July 2022.
- ^ United Press International (19 December 2009). "Sticking out your tongue ruled illegal". Rome, Italy. Retrieved 17 September 2017.
- PMID 16262620.
- ^
Teilhet-Fisk, Jehanne (ed.). Dimensions of Polynesia: Fine Arts Gallery of San Diego, October 7-November 25, 1973. Fine Arts Gallery of San Diego. p. 115. Retrieved 15 April 2024.
The mouth forms of Polynesia are expressive and contain a great deal of variation, from the snarling lips of Hawaiian sculture to the tight-lipped, pursed mouths of the Easter Island statues. [...] The presence or absence of a tongue is helpful in considering the meaning of the mouth forms. The mouth forms showing protrusion of the tongue occur in the Marginal Islands (New Zealand, Hawaii, and the Marquesas), Central Polynesia (Tahiti and the Cook Islands) and the Australs.
- ^ Hawes, Charles Boardman (1924). Whaling. Doubleday.