Tonsil: Difference between revisions

Jump to navigation Jump to search
VisualWikitext
m (Robot: Automated text replacement (-{{SIB}} +, -{{EH}} +, -{{EJ}} +, -{{Editor Help}} +, -{{Editor Join}} +))
 
No edit summary
 
Line 1: Line 1:
__NOTOC__
{{SI}}
{{CMG}}


:''For the structure in the [[cerebellum]], see [[cerebellar tonsil]].''
==Overview==
<!-- Image with unknown copyright status removed: [[Image:Tonsils.jpg|thumb|200px|normal tonsils]] -->
The '''tonsils''' are areas of [[lymphatic system|lymphoid tissue]] on either side of the [[throat]]. An [[infection]] of the tonsils is called [[tonsillitis]]. Most commonly, the term "tonsils" refers to the [[palatine tonsils]] that can be seen in the back of the throat.


As with other organs of the [[lymphatic system]], the tonsils act as part of the [[immune system]] to help protect against infection. In particular, they are believed to be involved in helping fight off [[pharynx|pharyngeal]] and [[upper respiratory tract infection]]s.
The '''tongue''' is a [[muscular hydrostat]] on the floor of the mouth of most [[vertebrate]]s that manipulates food for [[mastication]]. It is the primary [[organ (anatomy)|organ]] of [[taste]] (gustation), as much of its upper surface is covered in [[taste buds]]. The tongue's upper surface is also covered in numerous [[lingual papilla]]e. It is sensitive and kept moist by [[saliva]], and is richly supplied with nerves and blood vessels. In humans a secondary function of the tongue is [[Articulatory phonetics|phonetic articulation]]. The tongue also serves as a natural means of [[oral hygiene|cleaning]] the teeth.<ref>{{cite book |last1=Maton |first1=Anthea |last2=Hopkins |first2=Jean |last3=McLaughlin |first3=Charles William |last4=Johnson |first4=Susan |last5=Warner |first5=Maryanna Quon |last6=LaHart |first6=David |last7=Wright |first7=Jill D. |title=Human Biology and Health |publisher=Prentice Hall |year=1993 |location=Englewood Cliffs, New Jersey, USA |isbn=0-13-981176-1}}</ref> The ability to perceive different tastes is not localised in different parts of the tongue, as is widely believed.<ref>[http://www.scientificamerican.com/article.cfm?id=the-taste-map-all-wrong The Taste Map: All Wrong], ''[[Scientific American]], March 18, 2001.</ref> This error arose because of misinterpretation of some 19th-century research (see [[tongue map]]).


Tonsils in humans include, from superior to inferior:
==Structure==
The tongue is a muscular structure that forms part of the floor of the [[oral cavity]]. The left and right sides of the tongue are separated by the [[lingual septum]]. The human tongue is divided into [[Anatomical terms of location#Anterior and posterior|anterior and posterior]] parts. The anterior part is the visible part situated at the front and makes up roughly two-thirds the length of the tongue. The posterior part is the part closest to the throat,  roughly one-third of its length. These parts differ in terms of their embryological development and nerve supply. The two parts of the tongue are divided by the [[Terminal sulcus (tongue)|terminal sulcus]].<ref name=GRAYS2005>{{cite book|last=Drake|first=Richard L.|title=Gray's anatomy for students|year=2005|publisher=Elsevier/Churchill Livingstone|location=Philadelphia|isbn=978-0-8089-2306-0|author2=Vogl, Wayne |author3=Tibbitts, Adam W.M. Mitchell  |author4=illustrations by Richard |author5= Richardson, Paul }}</ref>{{rp|989–990}}


{| class="wikitable"
The anterior tongue is, at its apex, thin and narrow, it is directed forward against the lingual surfaces of the lower [[incisor]] teeth. The posterior part is, at its root, directed backward, and connected with the [[hyoid bone]] by the [[hyoglossi]] and [[genioglossi]] muscles and the [[hyoglossal membrane]], with the [[epiglottis]] by three folds (glossoepiglottic) of mucous membrane, with the [[soft palate]] by the [[glossopalatine arches]], and with the [[pharynx]] by the [[superior pharyngeal constrictor muscle]] and the [[mucous membrane]]. It also forms the anterior wall of the [[oropharynx]].
| '''Name''' || '''[[Epithelium]]''' || '''[[Capsule (anatomy)|Capsule]]?''' || '''[[Crypt (anatomy)|Crypts]]?''' || '''Location'''
|-
| [[adenoids]] (also termed "pharyngeal tonsils") || [[pseudostratified epithelium|ciliated pseudostratified]] ([[respiratory epithelium]]) || Incompletely encapsulated || No || roof of [[pharynx]]  
|-
| [[palatine tonsils]] || [[stratified squamous epithelium|non-keratinized stratified squamous]] || Incompletely encapsulated || Yes || sides of [[pharynx]] between glossopalatine<br> and pharyngopalatine arches
|-
| [[lingual tonsils]] || [[stratified squamous epithelium|non-keratinized stratified squamous]] || Incompletely encapsulated || Yes || behind [[terminal sulcus (tongue)]]
|}


Together this set of lymphatic tissue is known as '''[[Waldeyer's tonsillar ring]]'''.   
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 consonant|apical]], while those made with the tongue blade are said to be [[laminal consonant|laminal]].


Tonsils tend to reach their largest size near [[puberty]], and they gradually undergo [[atrophy]] thereafter. However, they are largest relative to the diameter of the throat in young children, and [[tonsillectomy]] (surgical removal of tonsils) may be indicated if they are obstructing the airway or interfering with swallowing. Also, when tonsils become overly enlarged or inflamed they may need to be surgically removed.
===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.
 
<gallery>
File:Gray1020.png |Coronal section of tongue, showing intrinsic muscles
File:Gray1019.png |Lateral view of the tongue, with extrinsic muscles highlighted.
</gallery>
 
====Extrinsic====
The extrinsic muscles originate from bone and extend to the tongue. Their main functions are altering the tongue's position allowing for protrusion, retraction, and side-to-side movement.<ref name=GRAYS2005 />{{rp|991}}
# [[Genioglossus]], which arises from the [[mandible]] and protrudes the tongue. It is also known as the "safety muscle" of the tongue since it is the only muscle having the forward action.
# [[Hyoglossus]], which arises from the [[hyoid bone]] and depresses the tongue
# [[Styloglossus]], which arises from the [[styloid process]] of the temporal bone and elevates and retracts the tongue
# [[Palatoglossus]], which arises from the [[palatine aponeurosis]], and depresses the [[soft palate]], moves the ''palatoglossal fold'' towards the midline, and elevates the back of the tongue.
 
====Intrinsic====
Four paired intrinsic muscles of the tongue originate and insert within the tongue, running along its length. These muscles alter the shape of the tongue by: lengthening and shortening it, curling and uncurling its apex and edges, and flattening and rounding its surface. This provides shape, and helps facilitate speech, swallowing, and eating.<ref name=GRAYS2005 />{{rp|991}}
# The [[superior longitudinal muscle of tongue|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.
# The [[inferior longitudinal muscle of tongue|inferior longitudinal muscle]] lines the sides of the tongue, and is joined to the styloglossus muscle.
# The [[vertical muscle of tongue|vertical muscle]] is located in the middle of the tongue, and joins the superior and inferior longitudinal muscles.
# The [[transverse muscle of tongue|transverse muscle]] divides the tongue at the middle, and is attached to the [[mucous membrane]]s that run along the sides.
 
===Blood supply===
The tongue receives its [[blood]] supply primarily from the [[lingual artery]], a branch of the [[external carotid artery]]. The [[lingual veins]], drain into the [[internal jugular vein]]. The floor of the mouth also receives its blood supply from the lingual artery.<ref name=GRAYS2005 />{{rp|993–994}} There is also a secondary blood supply to the tongue from the [[tonsillar branch of the facial artery]] and the [[ascending pharyngeal artery]].
 
An area in the neck sometimes called [[Pirogov Triangle|Pirogov's triangle]] is formed by the intermediate tendon of the [[digastric muscle]], the posterior border of the [[mylohyoid muscle]], and the [[hypoglossal]] nerve.<ref>[http://www.whonamedit.com/synd.cfm/3186.html Pirogov's triangle]</ref><ref>{{cite journal |title=Topographic anatomy of lingual arterial anastomoses; Pirogov-Belclard's triangle |last1=Jamrozik |first1=T. |last2=Wender |first2=W. |journal=Folia Morphologica |volume=3 |issue=1 |pages=51–62 |date=January 1952 |pmid=13010300}}</ref> The lingual artery is a good place to stop severe [[hemorrage]] from the tongue.
 
===Innervation===
Innervation of the tongue consists of motor fibers, [[special visceral afferent|special sensory]] fibers for taste, and [[general visceral afferent|general sensory]] fibers for sensation.<ref name=GRAYS2005 />{{rp|994–5}}
 
*Motor supply for all intrinsic and extrinsic muscles of the tongue is supplied by [[efferent nerve fiber|efferent motor nerve fibers]] from the [[hypoglossal nerve]] (CN XII), with the exception of the [[palatoglossus]]. The palatoglossus is innervated by the [[vagus nerve]] (CN X).<ref name=GRAYS2005 />{{rp|995}}
 
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 arch 3 and 4, respectively).<ref>{{Cite book | edition = Sixth
| publisher = LWW | isbn = 9781451190380 | last = PhD | first = Dr Ronald W. Dudek | title = BRS Embryology | date = 2014}}</ref>
 
*Anterior two thirds of tongue (anterior to the [[Lingual papilla#Circumvallate papillae|vallate papillae]]):
**Taste: chorda tympani branch of the [[facial nerve]] (CN VII) via [[special visceral afferent]] fibers
**Sensation: lingual branch of the mandibular division (V3) of the [[trigeminal nerve]] (CN V) via [[general somatic afferent]] fibers
 
*Posterior one third of tongue:
**Taste and sensation: [[glossopharyngeal nerve]] (CN IX) via a mixture of special and general visceral afferent fibers
 
===Histology===
The tongue is covered with numerous [[taste bud]]s, and [[filiform papillae|filiform]], [[fungiform papillae|fungiform]], [[vallate papillae|vallate]] and [[foliate papillae|foliate]], [[lingual papilla]]e.<ref name=GRAYS2005 />{{rp|990}}
 
===Length===
The average length of the human tongue from the [[oropharynx]] to the tip is 10cms in length.<ref>{{cite book |year=1997 |last=Kerrod |first=Robin |title=MacMillan's Encyclopedia of Science |publisher=Macmillan Publishing Company, Inc. |volume=6 |isbn=0-02-864558-8}}</ref>
 
===Development===
The anterior tongue is derived primarily from the [[first pharyngeal arch]]. The posterior tongue is derived primarily from the third [[pharyngeal arch]]. The second arch however has a substantial contribution during fetal development, but this later atrophies. The fourth arch may also contribute, depending upon how the boundaries of the tongue are defined.
 
The terminal sulcus, which separates the anterior and posterior tongue, is shaped like a V, with the tip of the V situated posteriorly. At the apex is the [[foramen caecum]], which is the point where the embryological [[thyroid]] begins to descend.<ref name=GRAYS2005 />{{rp|990}}
 
==Function==
{{multiple image
| align    = right
| direction = horizontal
| width    = 250
| image1    = Tongue_and_taste_buds.jpg
| width1    = 250
| alt1      = Human tongue and taste buds
| image2    = 1402 The Tongue.jpg
| width2    = 240
| alt2      = Taste receptors in papillae
| footer    = Taste receptors are present on the human tongue in papillae
| footer_align      = center
}}
 
===Taste===
Chemicals that stimulate [[taste receptor]] cells are known as tastants. Once a tastant is dissolved in [[saliva]], it can make contact with the [[plasma membrane]] of the gustatory hairs, which are the sites of taste [[transduction (physiology)|transduction]].<ref>Tortora. ''Principles of Anatomy and Physiology'' 12th edition, chapter 17, p.602.</ref>
 
The tongue is equipped with many [[taste buds]] on its [[Anatomical terms of location|dorsal]] surface, and each taste bud is equipped with taste receptor cells that can sense particular classes of tastes. Distinct types of taste receptor cells respectively detect substances that are sweet, bitter, salty, sour, spicy, or taste of [[umami]].<ref>Silverhorn. ''Human Physiology: An integrated approach'' 5th edition, chapter 10, p.352.</ref> Umami receptor cells are the least understood and accordingly are the type most intensively under research.<ref>Schacter, Daniel L., Daniel Todd. Gilbert, and Daniel M. Wegner. "Sensation and Perception." Psychology. 2nd ed. New York: Worth, 2009. 166. Print.</ref>
 
===Mastication===
The tongue is also used for crushing food against the hard palate, during mastication. The [[epithelium]] on the tongue’s upper, or dorsal surface is [[keratin]]ised. Consequently, the tongue can grind against the hard palate without being itself damaged or irritated.<ref>Atkinson. "Anatomy for dental students'' 4th edition.</ref>
 
===Swallowing===
 
===Speech===
 
==Clinical relevance==
 
===Disease===
 
After the [[Gingiva|gum]]s, the tongue is the second most common [[soft tissue]] site for various [[pathology|pathologies]] in the [[oral cavity]].{{medical citation needed|date=July 2013}} Examples of pathological conditions of the tongue include [[glossitis]] (e.g. [[geographic tongue]], [[median rhomboid glossitis]]), [[burning mouth syndrome]], [[oral hairy leukoplakia]], [[oral candidiasis]] and [[squamous cell carcinoma]].<ref name="SCC">{{cite journal |last1=Lam |first1=L. |last2=Logan |first2=R. M. |last3=Luke |first3=C. |title=Epidemiological analysis of tongue cancer in South Australia for the 24-year period, 1977-2001 |journal=Aust Dent J |volume=51 |issue=1 |pages=16–22 |date=March 2006 |pmid=16669472 |doi=10.1111/j.1834-7819.2006.tb00395.x}}</ref> Food debris, desquamated epithelial cells and bacteria often form a visible tongue coating.<ref name=Newman2012>{{cite book|last=(editors) Newman MG, Takei HH, Klokkevold PR, Carranza FA|title=Carranza's clinical periodontology|year=2012|publisher=Elsevier/Saunders|location=St. Louis, Mo.|isbn=978-1-4377-0416-7|pages=84–96|edition=11th}}</ref> This coating has been identified as a major contributing factor in bad breath ([[halitosis]]),<ref name=Newman2012 /> which can be managed by brushing the tongue gently with a toothbrush or using special oral hygiene instruments such as tongue scrapers or mouth brushes.<ref name=Outhouse2006>{{cite journal|last=Outhouse|first=TL|author2=Al-Alawi, R |author3=Fedorowicz, Z |author4= Keenan, JV |title=Tongue scraping for treating halitosis.|journal=The Cochrane database of systematic reviews|date=Apr 19, 2006|issue=2|pages=CD005519|pmid=16625641 |doi=10.1002/14651858.CD005519.pub2}}</ref>
 
===Medical delivery===
The [[sublingual]] region underneath the front of the tongue is a location where the [[oral mucosa]] is very thin, and underlain by a plexus of veins. This is an ideal location for introducing certain medications to the body. The sublingual route takes advantage of the highly [[Blood vessel|vascular]] quality of the oral cavity, and allows for the speedy application of medication into the cardiovascular system, bypassing the gastrointestinal tract. This is the only convenient and efficacious route of administration (apart from [[Intravenous therapy|I.V.]] administration) of [[Glyceryl trinitrate (pharmacology)|nitroglycerin]] to a patient suffering chest pain from [[angina pectoris]].
 
==Society and culture==
 
===Figures of speech===
The tongue can be used as a [[metonymy|metonym]] for ''language'', as in the phrase ''[[mother tongue]]''. Many languages<ref>[[Afrikaans language|Afrikaans]] ''tong''; [[Danish language|Danish]] ''tunge''; [[Albanian language|Albanian]] ''gjuha''; [[Armenian language|Armenian]] ''lezu'' (լեզու); [[Greek language|Greek]] ''glóssa'' (γλώσσα); [[Irish language|Irish]] ''teanga''; [[Manx language|Manx]] ''çhengey''; [[Latin]] and [[Italian language|Italian]] ''lingua''; [[Catalan language|Catalan]] ''llengua''; [[French language|French]] ''langue''; [[Portuguese language|Portuguese]] ''língua''; [[Spanish language|Spanish]] ''lengua''; [[Romanian language|Romanian]] ''limba''; [[Bulgarian language|Bulgarian]] ''ezik'' (език); [[Polish language|Polish]] ''język''; [[Russian language|Russian]] ''yazyk'' (язык); [[Czech language|Czech]] and [[Slovak language|Slovak]] ''jazyk''; [[Slovene language|Slovene]], [[Bosnian language|Bosnian]], [[Croatian language|Croatian]], and [[Serbian language|Serbian]] ''jezik''; [[Kurdish language|Kurdish]] ''ziman'' (زمان); [[Persian language|Persian]] and [[Urdu]] ''zabān'' (زبان); [[Arabic]] ''lisān'' (لسان); [[Aramaic language|Aramaic]] ''liššānā'' (ܠܫܢܐ/לשנא); [[Hebrew language|Hebrew]] ''lāšon'' (לָשׁוֹן); [[Maltese language|Maltese]] ''ilsien''; [[Estonian language|Estonian]] ''keel''; [[Finnish language|Finnish]] ''kieli''; [[Hungarian language|Hungarian]] ''nyelv''; [[Azerbaijani language|Azerbaijani]] and [[Turkish language|Turkish]] ''dil''; [[Kazakh language|Kazakh]] and [[Khakas language|Khakas]] ''til'' (тіл)</ref> have the same word for "tongue" and "[[language]]".
 
A common temporary failure in word [[Recollection|retrieval]] from [[memory]] is referred to as the ''[[Tip of the tongue|tip-of-the-tongue]]'' [[phenomenon]]. The expression ''[[Tongue-in-cheek|tongue in cheek]]'' refers to a statement that is not to be taken entirely seriously – something said or done with subtle ironic or sarcastic humour. A ''[[tongue twister]]'' is a phrase made specifically to be very difficult to pronounce. Aside from being a [[Ankyloglossia|medical condition]], "tongue-tied" means being unable to say what you want to due to confusion or restriction. The phrase "cat got your tongue" refers to when a person is speechless. To "bite one's tongue" is a phrase which describes holding back an opinion to avoid causing offence. A "slip of the tongue" refers to an unintentional utterance, such as a [[Freudian slip]]. [[Speaking in tongues]] is a common phrase used to describe ''glossolalia'', which is to make smooth, language-resembling sounds that is no true spoken language itself. A deceptive person is said to have a [[forked tongue]], and a smooth-talking person said to have a {{Linktext|silver tongue}}.
 
===Gestures===
Sticking one's tongue out at someone is considered a childish gesture of [[rudeness]] and/or defiance in many countries; the act may also have  sexual connotations, depending on the way in which it is done. However, in [[Tibet]] it is considered a greeting.<ref>{{cite web |url=http://www.tibetwrites.org/?Tibetan-Culture-in-the-21st |title=Tibetan culture in the 21st century |author=Bhuchung K Tsering |date=27 December 2007 |accessdate=13 February 2012}}</ref> In 2009, a farmer from [[Fabriano]], Italy was convicted and fined by [[Court of Cassation (Italy)|the country's highest court]] for sticking his tongue out at a neighbor with whom he had been arguing. Proof of the affront had been captured with a cell phone camera.<ref name="UPI">[http://www.upi.com/Odd_News/2009/12/19/Sticking-out-your-tongue-ruled-illegal/UPI-71761261272837/ Sticking out your tongue ruled illegal]</ref> [[Blowing a raspberry]] can also be meant as a gesture of derision.{{cn|date=September 2015}}
 
===Body art===
Being a cultural custom for long time, [[tongue piercing]] and [[tongue splitting|splitting]] has become quite common in western countries in recent decades, with up to one-fifth of young adults having at least one piece of body art in the tongue.<ref name="DTLEVIN">{{cite journal |last1=Liran |first1=Levin |last2=Yehuda |first2=Zadik |last3=Tal |first3=Becker |title=Oral and dental complications of intra-oral piercing |journal=Dent Traumatol |volume=21 |issue=6 |pages=341–3 |date=December 2005 |pmid=16262620 |doi= 10.1111/j.1600-9657.2005.00395.x |accessdate=2008-07-16}}</ref>
 
===As food===
 
The tongues of some animals are consumed and sometimes considered delicacies. Hot tongue sandwiches are frequently found on menus in [[Kosher]] [[delicatessen]]s in America. [[Taco|Taco de lengua]] (''lengua'' being Spanish for tongue) is a taco filled with [[beef tongue]], and is especially popular in Mexican cuisine. As part of Colombian gastronomy, Tongue in Sauce (Lengua en Salsa), is a dish prepared by frying the tongue, adding tomato sauce, onions and salt.  Tongue can also be prepared as [[birria]]. Pig and beef tongue are consumed in Chinese cuisine. [[Duck]] tongues are sometimes employed in [[Szechuan cuisine|Szechuan]] dishes, while [[Lamb (food)|lamb]]'s tongue is occasionally employed in Continental and contemporary American cooking. Fried [[cod]] "tongue" is a relatively common part of fish meals in [[Norway]] and [[Newfoundland and Labrador|Newfoundland]]. In [[Argentina]] and [[Uruguay]] cow tongue is cooked and served in vinegar (''lengua a la vinagreta'').  In the Czech Republic and Poland, a pork tongue is considered a delicacy, and there are many ways of preparing it. In Eastern Slavic countries, pork and beef tongues are commonly consumed, boiled and garnished with horseradish or jelled; beef tongues fetch a significantly higher price and are considered more of a delicacy.  In Alaska, cow tongues are among the more common.
 
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.<ref>CHARLES BOARDMAN HAWES. Whaling. Doubleday, 1924</ref>
 
==History==
 
===Etymology===
The word '''tongue''' derives from the [[Old English]] ''tunge'', which comes from [[Proto-Germanic]] *''tungōn''.<ref name="OED">[http://www.etymonline.com/index.php?term=tongue Online Etymology Dictionary]</ref> It has [[cognates]] in other [[Germanic languages]] — for example ''tonge'' in [[West Frisian language|West Frisian]], ''tong'' in [[Dutch language|Dutch]]/[[Afrikaans]], ''Zunge'' in [[German language|German]], ''tunge'' in [[Danish language|Danish]]/[[Norwegian language|Norwegian]] and ''tunga'' in [[Icelandic language|Icelandic]]/[[Faroese language|Faroese]]/[[Swedish language|Swedish]]. The ''ue'' ending of the word seems to be a fourteenth-century attempt to show "proper pronunciation", but it is "neither etymological nor phonetic".<ref name="OED"/> Some used the spelling ''tunge'' and ''tonge'' as late as the sixteenth century.
 
==Other animals==
Most [[vertebrate]] animals have tongues. In mammals such as [[dog]]s and [[cat]]s, the tongue is often used to clean the fur and body. The tongues of these species have a very rough texture which allows them to remove oils and parasites. A dog's tongue also acts as a heat regulator. As a dog increases its exercise the tongue will increase in size due to greater blood flow. The tongue hangs out of the dog's mouth and the moisture on the tongue will work to cool the bloodflow.<ref>[http://www.doctordog.com/drdognewsletter/tongue.html A dog's tongue]</ref><ref>{{cite journal |title=Lingual blood flow and its hypothalamic control in the dog during panting |journal=[[Pflügers Archiv European Journal of Physiology]] |date=January 1976 |issn=0031-6768 |doi=10.1007/BF00583652 |pages=25–31 |volume=367 |issue=1 |last1=Krönert |first1=H. |last2=Pleschka |first2=K. |accessdate=June 24, 2011}}</ref>
 
Some animals have tongues that are specially adapted for catching prey. For example, [[chameleon]]s, [[frog]]s, and [[anteater]]s have [[prehensility|prehensile]] tongues.
 
Many species of fish have small folds at the base of their mouths that might informally be called tongues, but they lack a muscular structure like the true tongues found in most [[tetrapod]]s.<ref name=VB>{{cite book |last1=Romer |first1=Alfred Sherwood |last2=Parsons |first2=Thomas S. |year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA |pages=298–299 |isbn= 0-03-910284-X}}</ref><ref>{{cite book |last=Kingsley |first=John Sterling |year=1912 |title=Comparative anatomy of vertebrates |publisher=P. Blackiston's Son & Co. |pages=217–220 |isbn= 1-112-23645-7}}</ref>
 
Other animals may have organs that are [[analogy (biology)|analogous]] to tongues, such as a [[butterfly]]'s [[proboscis]] or a [[radula]] on a [[mollusca|mollusc]], but these are not [[Homology (biology)|homologous]] with the tongues found in vertebrates, and often have little resemblance in function, for example, butterflies do not lick with their proboscides; they suck through them, and the proboscis is not a single organ, but two jaws held together to form a tube.<ref name= "isbn0-412-61390-5">{{cite book |last1=Richards |first1=O. W. |last2=Davies |first2=R. G. |title=Imms' General Textbook of Entomology: Volume 1: Structure, Physiology and Development Volume 2: Classification and Biology |publisher=Springer |location=Berlin |year=1977 |isbn=0-412-61390-5}}</ref>
[[File:Macroglossum stellatarum anatomy - MHNT.jpg|thumb|''[[Macroglossum]]'': View of the extended proboscis, which inspired the name of the animal, literally "long-tongue"]]
 
==Additional Images==


==See also==
==See also==
* [[Tubal tonsil]]
{{Anatomy-terms}}
* [[Tonsilloliths]]
{{col-begin}}{{col-break}}
* [[Tonsillitis]]
* [[Ankyloglossia]]
* [[Tonsillectomy]]
* [[Electronic tongue]]
* [[Language]]
* [[Licking]]
* [[List of Mendelian traits in humans]] {{nb10}}
* [[Oral cancer]]
* [[Taste bud]]
* [[Tip of the tongue]]
{{col-break}}
* [[Tongue splitting]]
* [[Tongue cleaner]]
* [[Tongue disease]]
* [[Tongue piercing]]
* [[Tongue rolling]]
* [[Tongue-twister]]
* [[Vocal tract]]
{{col-end}}
 
==References==
{{Gray's}}
{{Reflist|2}}


==External links==
==External links==
* {{eMedicineDictionary|Tonsil}}
{{Commons category|tongue}}
* [http://www.med.umich.edu/1libr/aha/aha_headthro_art.htm Image of all tonsils at www.med.umich.edu]
{{wikiquote}}
{{Wiktionary}}
*[http://www.umanitoba.ca/faculties/arts/linguistics/russell/138/sec1/anatomy.htm University of Manitoba, Anatomy of the Vocal Tract]


{{Lymphatics of head and neck}}
{{Mouth anatomy}}
{{Gustatory system}}
{{Taste}}


[[Category:Head and neck]]
{{Authority control}}
[[Category:Otolaryngology]]


[[de:Tonsille]]
[[Category:Sensory organs]]
[[es:Amígdala]]
[[Category:Gustatory system]]
[[eo:Tonsilo]]
[[Category:Tongue|*]]
[[fr:Tonsille]]
[[Category:Digestive system]]
[[gl:Amígdala]]
[[Category:Human mouth anatomy]]
[[hr:Tonzile]]
[[id:Mandel]]
[[it:Tonsille]]
[[he:שקדים]]
[[nl:Keelamandel]]
[[ja:扁桃]]
[[pl:Migdałki podniebienne]]
[[pt:Tonsila]]
[[sv:Tonsill]]
[[th:ทอนซิล]]
[[tr:Bademcik]]
[[yi:מאנדלען]]
{{WH}}
{{WikiDoc Sources}}

Latest revision as of 19:13, 23 December 2015

WikiDoc Resources for Tonsil

Articles

Most recent articles on Tonsil

Most cited articles on Tonsil

Review articles on Tonsil

Articles on Tonsil in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Tonsil

Images of Tonsil

Photos of Tonsil

Podcasts & MP3s on Tonsil

Videos on Tonsil

Evidence Based Medicine

Cochrane Collaboration on Tonsil

Bandolier on Tonsil

TRIP on Tonsil

Clinical Trials

Ongoing Trials on Tonsil at Clinical Trials.gov

Trial results on Tonsil

Clinical Trials on Tonsil at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Tonsil

NICE Guidance on Tonsil

NHS PRODIGY Guidance

FDA on Tonsil

CDC on Tonsil

Books

Books on Tonsil

News

Tonsil in the news

Be alerted to news on Tonsil

News trends on Tonsil

Commentary

Blogs on Tonsil

Definitions

Definitions of Tonsil

Patient Resources / Community

Patient resources on Tonsil

Discussion groups on Tonsil

Patient Handouts on Tonsil

Directions to Hospitals Treating Tonsil

Risk calculators and risk factors for Tonsil

Healthcare Provider Resources

Symptoms of Tonsil

Causes & Risk Factors for Tonsil

Diagnostic studies for Tonsil

Treatment of Tonsil

Continuing Medical Education (CME)

CME Programs on Tonsil

International

Tonsil en Espanol

Tonsil en Francais

Business

Tonsil in the Marketplace

Patents on Tonsil

Experimental / Informatics

List of terms related to Tonsil

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

The tongue is a muscular hydrostat on the floor of the mouth of most vertebrates that manipulates food for mastication. It is the primary organ of taste (gustation), as much of its upper surface is covered in taste buds. The tongue's upper surface is also covered in numerous lingual papillae. It is sensitive and kept moist by saliva, and is richly supplied with nerves and blood vessels. In humans a secondary function of the tongue is phonetic articulation. The tongue also serves as a natural means of cleaning the teeth.[1] The ability to perceive different tastes is not localised in different parts of the tongue, as is widely believed.[2] This error arose because of misinterpretation of some 19th-century research (see tongue map).

Structure

The tongue is a muscular structure that forms part of the floor of the oral cavity. The left and right sides of the tongue are separated by the lingual septum. The human tongue is divided into anterior and posterior parts. The anterior part is the visible part situated at the front and makes up roughly two-thirds the length of the tongue. The posterior part is the part closest to the throat, roughly one-third of its length. These parts differ in terms of their embryological development and nerve supply. The two parts of the tongue are divided by the terminal sulcus.[3]:989–990

The anterior tongue is, at its apex, thin and narrow, it is directed forward against the lingual surfaces of the lower incisor teeth. The posterior part is, at its root, directed backward, and connected with the hyoid bone by the hyoglossi and genioglossi muscles and the hyoglossal membrane, with the epiglottis by three folds (glossoepiglottic) of mucous membrane, with the soft palate by the glossopalatine arches, and with the pharynx by the superior pharyngeal constrictor muscle and the mucous membrane. It also forms the anterior wall of the oropharynx.

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.

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.

  • Coronal section of tongue, showing intrinsic muscles

    Coronal section of tongue, showing intrinsic muscles

  • Lateral view of the tongue, with extrinsic muscles highlighted.

    Lateral view of the tongue, with extrinsic muscles highlighted.

Extrinsic

The extrinsic muscles originate from bone and extend to the tongue. Their main functions are altering the tongue's position allowing for protrusion, retraction, and side-to-side movement.[3]:991

  1. Genioglossus, which arises from the mandible and protrudes the tongue. It is also known as the "safety muscle" of the tongue since it is the only muscle having the forward action.
  2. Hyoglossus, which arises from the hyoid bone and depresses the tongue
  3. Styloglossus, which arises from the styloid process of the temporal bone and elevates and retracts the tongue
  4. Palatoglossus, which arises from the palatine aponeurosis, and depresses the soft palate, moves the palatoglossal fold towards the midline, and elevates the back of the tongue.

Intrinsic

Four paired intrinsic muscles of the tongue originate and insert within the tongue, running along its length. These muscles alter the shape of the tongue by: lengthening and shortening it, curling and uncurling its apex and edges, and flattening and rounding its surface. This provides shape, and helps facilitate speech, swallowing, and eating.[3]:991

  1. 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.
  2. The inferior longitudinal muscle lines the sides of the tongue, and is joined to the styloglossus muscle.
  3. The vertical muscle is located in the middle of the tongue, and joins the superior and inferior longitudinal muscles.
  4. The transverse muscle divides the tongue at the middle, and is attached to the mucous membranes that run along the sides.

Blood supply

The tongue receives its blood supply primarily from the lingual artery, a branch of the external carotid artery. The lingual veins, drain into the internal jugular vein. The floor of the mouth also receives its blood supply from the lingual artery.[3]:993–994 There is also a secondary blood supply to the tongue from the tonsillar branch of the facial artery and the ascending pharyngeal artery.

An area in the neck sometimes called Pirogov's triangle is formed by the intermediate tendon of the digastric muscle, the posterior border of the mylohyoid muscle, and the hypoglossal nerve.[4][5] The lingual artery is a good place to stop severe hemorrage from the tongue.

Innervation

Innervation of the tongue consists of motor fibers, special sensory fibers for taste, and general sensory fibers for sensation.[3]:994–5

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 arch 3 and 4, respectively).[6]

  • Posterior one third of tongue:
    • Taste and sensation: glossopharyngeal nerve (CN IX) via a mixture of special and general visceral afferent fibers

Histology

The tongue is covered with numerous taste buds, and filiform, fungiform, vallate and foliate, lingual papillae.[3]:990

Length

The average length of the human tongue from the oropharynx to the tip is 10cms in length.[7]

Development

The anterior tongue is derived primarily from the first pharyngeal arch. The posterior tongue is derived primarily from the third pharyngeal arch. The second arch however has a substantial contribution during fetal development, but this later atrophies. The fourth arch may also contribute, depending upon how the boundaries of the tongue are defined.

The terminal sulcus, which separates the anterior and posterior tongue, is shaped like a V, with the tip of the V situated posteriorly. At the apex is the foramen caecum, which is the point where the embryological thyroid begins to descend.[3]:990

Function

Human tongue and taste buds
Taste receptors in papillae
Taste receptors are present on the human tongue in papillae

Taste

Chemicals that stimulate taste receptor cells are known as tastants. Once a tastant is dissolved in saliva, it can make contact with the plasma membrane of the gustatory hairs, which are the sites of taste transduction.[8]

The tongue is equipped with many taste buds on its dorsal surface, and each taste bud is equipped with taste receptor cells that can sense particular classes of tastes. Distinct types of taste receptor cells respectively detect substances that are sweet, bitter, salty, sour, spicy, or taste of umami.[9] Umami receptor cells are the least understood and accordingly are the type most intensively under research.[10]

Mastication

The tongue is also used for crushing food against the hard palate, during mastication. 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.[11]

Swallowing

Speech

Clinical relevance

Disease

After the gums, the tongue is the second most common soft tissue site for various pathologies in the oral cavity.[medical citation needed] Examples of pathological conditions of the tongue include glossitis (e.g. geographic tongue, median rhomboid glossitis), burning mouth syndrome, oral hairy leukoplakia, oral candidiasis and squamous cell carcinoma.[12] Food debris, desquamated epithelial cells and bacteria often form a visible tongue coating.[13] This coating has been identified as a major contributing factor in bad breath (halitosis),[13] which can be managed by brushing the tongue gently with a toothbrush or using special oral hygiene instruments such as tongue scrapers or mouth brushes.[14]

Medical delivery

The sublingual region underneath the front of the tongue is a location where the oral mucosa is very thin, and underlain by a plexus of veins. This is an ideal location for introducing certain medications to the body. The sublingual route takes advantage of the highly vascular quality of the oral cavity, and allows for the speedy application of medication into the cardiovascular system, bypassing the gastrointestinal tract. This is the only convenient and efficacious route of administration (apart from I.V. administration) of nitroglycerin to a patient suffering chest pain from angina pectoris.

Society and culture

Figures of speech

The tongue can be used as a metonym for language, as in the phrase mother tongue. Many languages[15] have the same word for "tongue" and "language".

A common temporary failure in word retrieval from memory is referred to as the tip-of-the-tongue phenomenon. The expression tongue in cheek refers to a statement that is not to be taken entirely seriously – something said or done with subtle ironic or sarcastic humour. A tongue twister is a phrase made specifically to be very difficult to pronounce. Aside from being a medical condition, "tongue-tied" means being unable to say what you want to due to confusion or restriction. The phrase "cat got your tongue" refers to when a person is speechless. To "bite one's tongue" is a phrase which describes holding back an opinion to avoid causing offence. A "slip of the tongue" refers to an unintentional utterance, such as a Freudian slip. Speaking in tongues is a common phrase used to describe glossolalia, which is to make smooth, language-resembling sounds that is no true spoken language itself. A deceptive person is said to have a forked tongue, and a smooth-talking person said to have a silver tongue.

Gestures

Sticking one's tongue out at someone is considered a childish gesture of rudeness and/or defiance in many countries; the act may also have sexual connotations, depending on the way in which it is done. However, in Tibet it is considered a greeting.[16] In 2009, a farmer from Fabriano, Italy was convicted and fined by the country's highest court for sticking his tongue out at a neighbor with whom he had been arguing. Proof of the affront had been captured with a cell phone camera.[17] Blowing a raspberry can also be meant as a gesture of derision.[citation needed]

Body art

Being a cultural custom for long time, tongue piercing and splitting has become quite common in western countries in recent decades, with up to one-fifth of young adults having at least one piece of body art in the tongue.[18]

As food

The tongues of some animals are consumed and sometimes considered delicacies. Hot tongue sandwiches are frequently found on menus in Kosher delicatessens in America. Taco de lengua (lengua being Spanish for tongue) is a taco filled with beef tongue, and is especially popular in Mexican cuisine. As part of Colombian gastronomy, Tongue in Sauce (Lengua en Salsa), is a dish prepared by frying the tongue, adding tomato sauce, onions and salt. Tongue can also be prepared as birria. Pig and beef tongue are consumed in Chinese cuisine. Duck tongues are sometimes employed in Szechuan dishes, while lamb's tongue is occasionally employed in Continental and contemporary American cooking. Fried cod "tongue" is a relatively common part of fish meals in Norway and Newfoundland. In Argentina and Uruguay cow tongue is cooked and served in vinegar (lengua a la vinagreta). In the Czech Republic and Poland, a pork tongue is considered a delicacy, and there are many ways of preparing it. In Eastern Slavic countries, pork and beef tongues are commonly consumed, boiled and garnished with horseradish or jelled; beef tongues fetch a significantly higher price and are considered more of a delicacy. In Alaska, cow tongues are among the more common.

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.[19]

History

Etymology

The word tongue derives from the Old English tunge, which comes from Proto-Germanic *tungōn.[20] It has cognates in other Germanic languages — for example tonge in West Frisian, tong in Dutch/Afrikaans, Zunge in German, tunge in Danish/Norwegian and tunga in Icelandic/Faroese/Swedish. The ue ending of the word seems to be a fourteenth-century attempt to show "proper pronunciation", but it is "neither etymological nor phonetic".[20] Some used the spelling tunge and tonge as late as the sixteenth century.

Other animals

Most vertebrate animals have tongues. In mammals such as dogs and cats, the tongue is often used to clean the fur and body. The tongues of these species have a very rough texture which allows them to remove oils and parasites. A dog's tongue also acts as a heat regulator. As a dog increases its exercise the tongue will increase in size due to greater blood flow. The tongue hangs out of the dog's mouth and the moisture on the tongue will work to cool the bloodflow.[21][22]

Some animals have tongues that are specially adapted for catching prey. For example, chameleons, frogs, and anteaters have prehensile tongues.

Many species of fish have small folds at the base of their mouths that might informally be called tongues, but they lack a muscular structure like the true tongues found in most tetrapods.[23][24]

Other animals may have organs that are analogous to tongues, such as a butterfly's proboscis or a radula on a mollusc, but these are not homologous with the tongues found in vertebrates, and often have little resemblance in function, for example, butterflies do not lick with their proboscides; they suck through them, and the proboscis is not a single organ, but two jaws held together to form a tube.[25]

File:Macroglossum stellatarum anatomy - MHNT.jpg
Macroglossum: View of the extended proboscis, which inspired the name of the animal, literally "long-tongue"

Additional Images

See also

Template:Anatomy-terms

References

Template:Gray's

  1. ↑ Maton, Anthea; Hopkins, Jean; McLaughlin, Charles William; Johnson, Susan; Warner, Maryanna Quon; LaHart, David; Wright, Jill D. (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN 0-13-981176-1.
  2. ↑ The Taste Map: All Wrong, Scientific American, March 18, 2001.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Drake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. ISBN 978-0-8089-2306-0.
  4. ↑ Pirogov's triangle
  5. ↑ Jamrozik, T.; Wender, W. (January 1952). "Topographic anatomy of lingual arterial anastomoses; Pirogov-Belclard's triangle". Folia Morphologica. 3 (1): 51–62. PMID 13010300.
  6. ↑ PhD, Dr Ronald W. Dudek (2014). BRS Embryology (Sixth ed.). LWW. ISBN 9781451190380.
  7. ↑ Kerrod, Robin (1997). MacMillan's Encyclopedia of Science. 6. Macmillan Publishing Company, Inc. ISBN 0-02-864558-8.
  8. ↑ Tortora. Principles of Anatomy and Physiology 12th edition, chapter 17, p.602.
  9. ↑ Silverhorn. Human Physiology: An integrated approach 5th edition, chapter 10, p.352.
  10. ↑ Schacter, Daniel L., Daniel Todd. Gilbert, and Daniel M. Wegner. "Sensation and Perception." Psychology. 2nd ed. New York: Worth, 2009. 166. Print.
  11. ↑ Atkinson. "Anatomy for dental students 4th edition.
  12. ↑ Lam, L.; Logan, R. M.; Luke, C. (March 2006). "Epidemiological analysis of tongue cancer in South Australia for the 24-year period, 1977-2001". Aust Dent J. 51 (1): 16–22. doi:10.1111/j.1834-7819.2006.tb00395.x. PMID 16669472.
  13. ↑ 13.0 13.1 (editors) Newman MG, Takei HH, Klokkevold PR, Carranza FA (2012). Carranza's clinical periodontology (11th ed.). St. Louis, Mo.: Elsevier/Saunders. pp. 84–96. ISBN 978-1-4377-0416-7.
  14. ↑ Outhouse, TL; Al-Alawi, R; Fedorowicz, Z; Keenan, JV (Apr 19, 2006). "Tongue scraping for treating halitosis". The Cochrane database of systematic reviews (2): CD005519. doi:10.1002/14651858.CD005519.pub2. PMID 16625641.
  15. ↑ Afrikaans tong; Danish tunge; Albanian gjuha; Armenian lezu (լեզու); Greek glóssa (γλώσσα); Irish teanga; Manx çhengey; Latin and Italian lingua; Catalan llengua; French langue; Portuguese língua; Spanish lengua; Romanian limba; Bulgarian ezik (език); Polish język; Russian yazyk (язык); Czech and Slovak jazyk; Slovene, Bosnian, Croatian, and Serbian jezik; Kurdish ziman (زمان); Persian and Urdu zabān (زبان); Arabic lisān (لسان); Aramaic liššānā (ܠܫܢܐ/לשנא); Hebrew lāšon (לָשׁוֹן); Maltese ilsien; Estonian keel; Finnish kieli; Hungarian nyelv; Azerbaijani and Turkish dil; Kazakh and Khakas til (тіл)
  16. ↑ Bhuchung K Tsering (27 December 2007). "Tibetan culture in the 21st century". Retrieved 13 February 2012.
  17. ↑ Sticking out your tongue ruled illegal
  18. ↑ Liran, Levin; Yehuda, Zadik; Tal, Becker (December 2005). "Oral and dental complications of intra-oral piercing". Dent Traumatol. 21 (6): 341–3. doi:10.1111/j.1600-9657.2005.00395.x. PMID 16262620. |access-date= requires |url= (help)
  19. ↑ CHARLES BOARDMAN HAWES. Whaling. Doubleday, 1924
  20. ↑ 20.0 20.1 Online Etymology Dictionary
  21. ↑ A dog's tongue
  22. ↑ Krönert, H.; Pleschka, K. (January 1976). "Lingual blood flow and its hypothalamic control in the dog during panting". Pflügers Archiv European Journal of Physiology. 367 (1): 25–31. doi:10.1007/BF00583652. ISSN 0031-6768. |access-date= requires |url= (help)
  23. ↑ Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 298–299. ISBN 0-03-910284-X.
  24. ↑ Kingsley, John Sterling (1912). Comparative anatomy of vertebrates. P. Blackiston's Son & Co. pp. 217–220. ISBN 1-112-23645-7.
  25. ↑ Richards, O. W.; Davies, R. G. (1977). Imms' General Textbook of Entomology: Volume 1: Structure, Physiology and Development Volume 2: Classification and Biology. Berlin: Springer. ISBN 0-412-61390-5.

External links

Template:Mouth anatomy Template:Gustatory system Template:Taste

Lua error in Module:Authority_control at line 788: attempt to index field 'wikibase' (a nil value).

Retrieved from "https://www.wikidoc.org/index.php?title=Tonsil&oldid=1197109"