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The tongue is a
muscular MUSCULAR (DS-200B), located in the United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain,Usage is mixed. The Guardian' and Telegraph' use Britain as a synonym for the Uni ...

muscular
organ Organ may refer to: Biology * Organ (anatomy) An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems. A given organ's tissues can be broadly cate ...
in the
mouth In animal anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science which deals with the structural organization ...

mouth
of a typical
tetrapod Tetrapods (; ) are four-limbed animals constituting the superclass Tetrapoda (). It includes extant Extant is the opposite of the word extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a sp ...
. It manipulates food for
mastication Chewing or mastication is the process by which food Food is any substance consumed to provide nutritional support for an organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any indiv ...
and
swallowing Swallowing, sometimes called deglutition in scientific contexts, is the process in the human or animal body that allows for a substance to pass from the mouth In animal anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of ...
as part of the
digestive process
digestive process
, and is the primary organ of
taste The gustatory system or sense of taste is the sensory system The sensory nervous system is a part of the nervous system In biology Biology is the natural science that studies life and living organisms, including their anatomy, ph ...

taste
. The tongue's upper surface (dorsum) is covered by
taste buds Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as lingual papillae, papillae found on the upper surface of the tongue, soft palate, upper e ...

taste buds
housed in numerous
lingual papilla Lingual papillae (singular papilla) are the small, nipple The nipple is a raised region of tissue on the surface of the breast The breast is one of two prominences located on the upper ventral Standard anatomical terms of location deal ...
e. It is sensitive and kept moist by
saliva Saliva (commonly referred to as spit) is an extracellular fluid In cell biology Cell biology (also cellular biology or cytology) is a branch of biology Biology is the natural science that studies life and living organisms, including t ...
and is richly supplied with
nerve A nerve is an enclosed, cable-like bundle of fibers (called axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences Despite the various English dialects Dialect The term diale ...

nerve
s and
blood vessel The blood vessels are the components of the circulatory system The circulatory system, also called the cardiovascular system or the vascular system, is an organ system An organ system is a biological system A biological system is a comp ...
s. The tongue also serves as a natural means of
cleaning Cleaning is the process of removing unwanted substances, such as dirt, infectious agents, and other impurities, from an object or environment. Cleaning occurs in many different contexts, and uses many different methods. Several occupations are de ...
the teeth. A major function of the tongue is the enabling of
speech Speech is human vocal communication Communication (from Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''c ...

speech
in
human Humans (''Homo sapiens'') are the most abundant and widespread species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A speci ...

human
s and
vocalization
vocalization
in other animals. The human tongue is divided into two parts, an
oral The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or oral ...
part at the front and a
pharyngeal
pharyngeal
part at the back. The left and right sides are also separated along most of its length by a vertical section of
fibrous tissue Fiber or fibre (from la, fibra, links=no) is a #Natural fibers, natural or #Man-made fibers, man-made substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineeri ...
(the lingual septum) that results in a groove, the median sulcus, on the tongue's surface. 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
Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language English is a West Germanic language of the Indo-European language family The Indo-European languages are a language family A language ...
''tunge'', which comes from
Proto-Germanic Proto-Germanic (abbreviated PGmc; also called Common Germanic) is the reconstructed Reconstruction may refer to: Politics, history, and sociology *Reconstruction (law), the transfer of a company's (or several companies') business to a new ...
*''tungōn''. It has
cognates In linguistics Linguistics is the scientific study of language A language is a structured system of communication Communication (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Itali ...
in other
Germanic languages The Germanic languages are a branch of the Indo-European The Indo-European languages are a language family native to western and southern Eurasia. It comprises most of the languages of Europe together with those of the northern Indian su ...

Germanic languages
—for example ''tonge'' in West Frisian, ''tong'' in
Dutch Dutch commonly refers to: * Something of, from, or related to the Netherlands * Dutch people () * Dutch language () *Dutch language , spoken in Belgium (also referred as ''flemish'') Dutch may also refer to:" Castle * Dutch Castle Places * ...
and
Afrikaans Afrikaans (, ) is a West Germanic language spoken in South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. With over 60 million people, it is the world's 23rd-most po ...
, ''Zunge'' in
German German(s) may refer to: Common uses * of or related to Germany * Germans, Germanic ethnic group, citizens of Germany or people of German ancestry * For citizens of Germany, see also German nationality law * German language The German la ...

German
, ''tunge'' in
Danish Danish may refer to: * Something of, from, or related to the country of Denmark * A national or citizen of Denmark, also called a "Dane", see Demographics of Denmark * Danish people or Danes, people with a Danish ancestral or ethnic identity * Danis ...
and
Norwegian Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in northwestern Europe *Norwegians, both a nation and an ethnic group native to Norway *Demographics of Norway *The Norwegian language, including the t ...
, and ''tunga'' in
Icelandic Icelandic refers to anything of, from, or related to Iceland and may refer to: *Icelandic people *Icelandic language *Icelandic alphabet *Icelandic cuisine See also

* Icelander (disambiguation) * Icelandic Airlines, a predecessor of Icelandai ...
,
Faroese Faroese ( ) or Faroish ( ) may refer to anything pertaining to the Faroe Islands, e.g.: *the Faroese language * the Faroese people {{Disambiguation Language and nationality disambiguation pages ...
and
Swedish Swedish or ' may refer to: * Anything from or related to Sweden, a country in Northern Europe * Swedish language, a North Germanic language spoken primarily in Sweden and Finland * Swedish alphabet, the official alphabet used by the Swedish langu ...
. The ''ue'' ending of the word seems to be a fourteenth-century attempt to show "proper pronunciation", but it is "neither etymological nor phonetic". Some used the spelling ''tunge'' and ''tonge'' as late as the sixteenth century.


In humans


Structure

The tongue is a
muscular hydrostat The tongue is a muscular hydrostat. A muscular hydrostat is a biological structure found in animals. It is used to manipulate items (including food) or to move its host about and consists mainly of muscles with no skeletal support. It performs its h ...
that forms part of the floor of the
oral cavity In animal anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of concerned with the study of the structure of s and their parts. Anatomy is a branch of natural science which deals with the structural organization of living thin ...
. The left and right sides of the tongue are separated by a vertical section of fibrous tissue known as the lingual septum. This division is along the length of the tongue save for the very back of the pharyngeal part and is visible as a groove called the median sulcus. The human tongue is divided into
anterior and posterior Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans. Terms used generally derive from Latin or Greek language, Greek roots and used to describe something in its standard anatomical position. This ...
parts by the terminal sulcus which is a V-shaped groove. The apex of the terminal sulcus is marked by a blind foramen, the foramen cecum, which is a remnant of the median
thyroid diverticulum The thyroid pouch or thyroid diverticulum is the embryological structure of the second pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryogenesis, embryonic development of vertebrates that ...
in early
embryonic development An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms ar ...

embryonic development
. The anterior ''oral'' part is the visible part situated at the front and makes up roughly two-thirds the length of the tongue. The posterior ''pharyngeal'' part is the part closest to the
throat In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebra, vertebrae. It contains the Human pharynx, pharynx and larynx. An important section of it is the epiglottis, separating the esophagus f ...

throat
, roughly one-third of its length. These parts differ in terms of their and . The anterior tongue is, at its apex, thin and narrow. It is directed forward against the lingual surfaces of the lower
incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth A tooth (plural teeth) is a hard, calcified Calcification is the accumulation of calcium salts in a Tissue (biology), body tissue. It normally occurs in the formation of bone ...
teeth. The posterior part is, at its root, directed backward, and connected with the
hyoid bone The hyoid bone (lingual bone or tongue-bone) () is a horseshoe A horseshoe is a fabricated product, normally made of metal A metal (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ε ...
by the hyoglossi and genioglossi muscles and the hyoglossal membrane, with the
epiglottis The epiglottis is a leaf-shaped flap in the throat In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebra, vertebrae. It contains the Human pharynx, pharynx and larynx. An important secti ...

epiglottis
by three glossoepiglottic folds of mucous membrane, with the
soft palate The soft palate (also known as the velum, palatal velum, or muscular palate) is, in mammal Mammals (from Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was origin ...
by the glossopalatine arches, and with the
pharynx The pharynx (plural: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea – the tubes going down to the stomach and the lungs. It is found in vertebrates and invertebrates, thou ...

pharynx
by the
superior pharyngeal constrictor muscle The superior pharyngeal constrictor muscle is a muscle in the pharynx The pharynx (plural: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea – the tubes going down to the s ...
and the
mucous membrane A mucous membrane or mucosa is a biological membrane, membrane that lines various cavities in the body and covers the surface of internal organs. It consists of one or more layers of Epithelium, epithelial cells overlying a layer of loose connect ...
. It also forms the anterior wall of the
oropharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity The nasal cavity is a large, air-filled space above and behind the nose A nose is a protuberance in vertebrate Vertebrates () comprise all speci ...
. The average length of the human tongue from the
oropharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity The nasal cavity is a large, air-filled space above and behind the nose A nose is a protuberance in vertebrate Vertebrates () comprise all speci ...
to the tip is 10 cm. The average weight of the human tongue from adult males is 70g and for adult females 60g. In
phonetics Phonetics is a branch of linguistics Linguistics is the scientific study of language, meaning that it is a comprehensive, systematic, objective, and precise study of language. Linguistics encompasses the analysis of every aspect of lang ...

phonetics
and
phonology Phonology is a branch of linguistics Linguistics is the scientific study of language, meaning that it is a comprehensive, systematic, objective, and precise study of language. Linguistics encompasses the analysis of every aspect of lan ...

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 Apical means "pertaining to an Apex (disambiguation), apex". It may refer to: *Apical ancestor, refers to the last common ancestor of an entire group, such as a species (biology) or a clan (anthropology) *Apical (anatomy), an anatomical term of loc ...
, while those made with the tongue blade are said to be laminal.


Upper surface of the tongue

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 thyroglossal duct and is formed during the descent of the
thyroid diverticulum The thyroid pouch or thyroid diverticulum is the embryological structure of the second pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryogenesis, embryonic development of vertebrates that ...
in
embryonic development An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms ar ...

embryonic development
. 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 part and an anterior
oral The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or oral ...
part. The pharyngeal part is supplied by the
glossopharyngeal nerve The glossopharyngeal nerve (), known as the ninth cranial nerve Cranial nerves are the nerve A nerve is an enclosed, cable-like bundle of nerve fibers called axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerv ...
and the oral part is supplied by the
lingual nerve The lingual nerve carries sensory innervation from the anterior two-thirds of the tongue. It contains fibres from both the mandibular division The mandibular nerve (V3) is the largest of the three divisions of the trigeminal nerve, the fifth crani ...
(a branch of the mandibular branch (V3) of the
trigeminal nerve The trigeminal nerve (the fifth cranial nerve, or simply CN V) is a nerve responsible for Sense, sensation in the face and motor functions such as biting and chewing; it is the most complex of the cranial nerves. Its name ("trigeminal" = ''tr ...

trigeminal nerve
) for somatosensory perception and by the
chorda tympani The chorda tympani is a branch of the facial nerve The facial nerve (the labyrinthine segment) is the seventh cranial nerve Cranial nerves are the nerve A nerve is an enclosed, cable-like bundle of nerve fibers called axon An axon (f ...
(a branch of the
facial nerve The facial nerve (the labyrinthine segment) is the seventh Cranial nerves, cranial nerve, or simply CN VII. It emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensation ...

facial nerve
) for . Both parts of the tongue develop from different
pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism that consists of mor ...
es.


Undersurface of the tongue

On the undersurface of the tongue is a fold of mucous membrane called the
frenulum A frenulum (or frenum, plural: frenula or frena, from the Latin ''frēnulum'', "little bridle", the diminutive A diminutive is a root word A root (or root word) is the core of a word that is irreducible into more meaningful elements. In morph ...
that tethers the tongue at the midline to the floor of the mouth. On either side of the frenulum are small prominences called s that the major salivary
submandibular gland The paired submandibular glands (historically known as submaxillary glands) are major salivary gland The salivary glands in mammals are exocrine glands that produce saliva through a system of Duct (anatomy), ducts. Humans have three paired major ...

submandibular gland
s drain into.


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
genioglossus The genioglossus is one of the paired extrinsic muscles of the tongue. The genioglossus is the major muscle responsible for protruding (or sticking out) the tongue. Structure Genioglossus is the fan-shaped extrinsic tongue muscle that forms the ma ...

genioglossus
, the
hyoglossus The hyoglossus, thin and quadrilateral, arises from the side of the body and from the whole length of the greater cornu The hyoid bone (lingual bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between ...

hyoglossus
(often including the chondroglossus) the
styloglossus The styloglossus, the shortest and smallest of the three styloid muscles, arises from the anterior and lateral surfaces of the Temporal styloid process, styloid process near its apex, and from the stylomandibular ligament. Passing inferiorly and an ...

styloglossus
, and the
palatoglossus The palatoglossus, glossopalatinus, or palatoglossal muscle is a small fleshy fasciculus, narrower in the middle than at either end, forming, with the mucous membrane covering its surface, the glossopalatine arch. Structure Palatoglossus arises fr ...
. Their main functions are altering the tongue's position allowing for protrusion, retraction, and side-to-side movement. The genioglossus arises from the
mandible In anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science which deals with the structural organization of li ...

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 The hyoid bone (lingual bone or tongue-bone) () is a horseshoe A horseshoe is a fabricated product, normally made of metal A metal (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ε ...
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 The temporal bones are situated at the sides and base of the skull The skull is a bone A bone is a rigid tissue Tissue may refer to: Biology * Tissue (biology), an ensemble of similar cells that together carry out a specific function ...

temporal bone
and draws the sides of the tongue up to create a trough for swallowing. The palatoglossus arises from the
palatine aponeurosis Attached to the posterior border of the hard palate The hard palate is a thin horizontal bony plate made up of two bones of the facial skeleton The facial skeleton comprises the ''facial bones'' that may attach to build a portion of the skull ...
, and depresses the
soft palate The soft palate (also known as the velum, palatal velum, or muscular palate) is, in mammal Mammals (from Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was origin ...
, 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 superior longitudinal muscle, the inferior longitudinal muscle, the vertical muscle, and the transverse muscle. These muscles alter the shape of the tongue by lengthening and shortening it, curling and uncurling its apex and edges as in
tongue rolling Image:Tongue rolled.jpg, A rolled tongue Tongue rolling is the ability to roll the lateral edges of the tongue upwards into a tube. The tongue's Muscles of tongue, intrinsic muscles allow some people to form their tongues into specific shapes. Popu ...
, and flattening and rounding its surface. This provides shape and helps facilitate speech, swallowing, and eating. The superior longitudinal muscle runs along the upper 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 epiglottis is a leaf-shaped flap in the throat In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebra, vertebrae. It contains the Human pharynx, pharynx and larynx. An important secti ...

epiglottis
, at the
hyoid bone The hyoid bone (lingual bone or tongue-bone) () is a horseshoe A horseshoe is a fabricated product, normally made of metal A metal (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ε ...
, from the median fibrous septum. The inferior longitudinal muscle lines the sides of the tongue, and is joined to the styloglossus muscle. The vertical muscle is located in the middle of the tongue, and joins the superior and inferior longitudinal muscles. The transverse muscle divides the tongue at the middle, and is attached to the
mucous membrane A mucous membrane or mucosa is a biological membrane, membrane that lines various cavities in the body and covers the surface of internal organs. It consists of one or more layers of Epithelium, epithelial cells overlying a layer of loose connect ...
s that run along the sides.


Blood supply

The tongue receives its
blood Blood is a body fluid Body fluids, bodily fluids, or biofluids are liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric process, isochoric flow) refers t ...

blood
supply primarily from the
lingual artery The lingual artery arises from the external carotid artery The external carotid artery is a major artery An artery (plural arteries) () is a blood vessel that takes blood away from the heart to one or more parts of the body (tissues, lungs, ...
, a branch of the
external carotid artery The external carotid artery is a major artery of the head and neck. It arises from the common carotid artery when it splits into the external and internal carotid artery. External carotid artery supplies blood to the face and neck. Structure Th ...

external carotid artery
. The
lingual veins The lingual veins begin on the dorsum, sides, and under surface of the tongue, and, passing backward along the course of the lingual artery, end in the internal jugular vein. The vena comitans of the hypoglossal nerve (ranine vein), a branch of co ...
drain into the
internal jugular vein The internal jugular vein is a paired jugular vein The jugular veins are vein Veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary vei ...
. The floor of the mouth also receives its blood supply from the lingual artery. There is also a secondary blood supply to the root of tongue from the
tonsillar branch of the facial artery The tonsillar branch of the facial artery ascends between the pterygoideus internus and styloglossus muscles, and then along the side of the pharynx, perforating the constrictor pharyngis superior, to ramify in the substance of the palatine tonsil a ...
and the
ascending pharyngeal artery The ascending pharyngeal artery is an artery An artery (plural arteries) () is a blood vessel The blood vessels are the components of the circulatory system The circulatory system, also called the cardiovascular system or the vascul ...
. An area in the neck sometimes called the Pirogov triangle is formed by the intermediate tendon of the
digastric muscle The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a small muscle Skeletal muscles (commonly referred to as muscles) are organs An organ is a group of tissues with similar functions. Plant life and an ...
, the posterior border of the
mylohyoid muscle The mylohyoid muscle or diaphragma oris is a paired muscle Muscle is a soft tissue found in most animals. Muscle cells contain protein Proteins are large biomolecules or macromolecules that are comprised of one or more long chains of am ...
, and the
hypoglossal The hypoglossal nerve is the twelfth cranial nerve, and innervates all the Tongue#Muscles, extrinsic and intrinsic muscles of the tongue, except for the palatoglossus which is innervated by the vagus nerve. It is a motor nerve, nerve with a sol ...
nerve. The lingual artery is a good place to stop severe
hemorrhage Bleeding, also known as a hemorrhage, haemorrhage, or simply blood loss, is blood Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the Cell (biology), cells and transports ...
from the tongue.


Nerve supply

Innervation of the tongue consists of motor fibers, special sensory fibers for taste, and general sensory fibers for sensation. * Motor supply for all intrinsic and extrinsic muscles of the tongue is supplied by efferent motor nerve fibers from the
hypoglossal nerve The hypoglossal nerve is the twelfth cranial nerve Cranial nerves are the nerve A nerve is an enclosed, cable-like bundle of nerve fibers called axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see ...
(CN XII), with the exception of the
palatoglossus The palatoglossus, glossopalatinus, or palatoglossal muscle is a small fleshy fasciculus, narrower in the middle than at either end, forming, with the mucous membrane covering its surface, the glossopalatine arch. Structure Palatoglossus arises fr ...
, which is innervated by the
vagus nerve The vagus nerve, historically cited as the pneumogastric nerve, is the tenth cranial nerve Cranial nerves are the nerve A nerve is an enclosed, cable-like bundle of nerve fibers called axon An axon (from Greek ἄξων ''áxōn'', axi ...
(CN X). 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 The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism that consists of mor ...
1 and pharyngeal arches 3 and 4, respectively). * Anterior two-thirds of tongue (anterior to the
vallate papillae Lingual papillae (singular papilla) are the small, nipple The nipple is a raised region of tissue on the surface of the breast The breast is one of two prominences located on the upper ventral region of the torso of primates. In females, ...
): ** Taste: chorda tympani branch of the
facial nerve The facial nerve (the labyrinthine segment) is the seventh Cranial nerves, cranial nerve, or simply CN VII. It emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensation ...

facial nerve
(CN VII) via
special visceral afferentA Special visceral afferent fibers (SVA) is a afferent fiber that develop in association with the gastrointestinal tract The gastrointestinal tract, (GI tract, GIT, digestive tract, digestion tract, alimentary canal) is the tract from the mouth ...
fibers ** Sensation: lingual branch of the mandibular (V3) division of the
trigeminal nerve The trigeminal nerve (the fifth cranial nerve, or simply CN V) is a nerve responsible for Sense, sensation in the face and motor functions such as biting and chewing; it is the most complex of the cranial nerves. Its name ("trigeminal" = ''tr ...

trigeminal nerve
(CN V) via
general visceral afferent The general visceral afferent (GVA) fibers conduct sensory impulses (usually pain or reflex sensations) from the internal organs An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many org ...
fibers * Posterior one third of tongue: ** Taste and sensation:
glossopharyngeal nerve The glossopharyngeal nerve (), known as the ninth cranial nerve Cranial nerves are the nerve A nerve is an enclosed, cable-like bundle of nerve fibers called axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerv ...
(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 The superior laryngeal nerve is a branch of the vagus nerve The vagus nerve, historically cited as the pneumogastric nerve, is the tenth cranial nerve or CN X, and interfaces with the parasympathetic control of the heart The heart is a m ...
(itself a branch of the
vagus nerve The vagus nerve, historically cited as the pneumogastric nerve, is the tenth cranial nerve Cranial nerves are the nerve A nerve is an enclosed, cable-like bundle of nerve fibers called axon An axon (from Greek ἄξων ''áxōn'', axi ...
, 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 The submandibular lymph nodes (submaxillary glands in older texts), three to six in number, are Lymph node, lymph nodes beneath the body of the mandible in the submandibular triangle, and rest on the superficial surface of the submandibular gland. ...
, while the posterior one-third of the tongue drains to the jugulo-omohyoid nodes.


Microanatomy

The upper surface of the tongue is covered in oral mucosa#Classification, masticatory mucosa, a type of oral mucosa which is of oral mucosa#Types, keratinized stratified squamous epithelium. Embedded in this are numerous lingual papilla, papillae, some of which house the taste buds and their taste receptors. The lingual papillae consist of filiform papillae, filiform, fungiform papillae, fungiform, vallate papillae, vallate and foliate papillae, and only the filiform papillae are not associated with any taste buds. 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. 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.


Development

The tongue begins to develop in the fourth week of human embryonic development, embryonic development from a median swelling – the median tongue bud (tuberculum impar) of the first pharyngeal arch. 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 Tongue#Upper surface of the tongue, median sulcus. In the fourth week a swelling appears from the second
pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development An embryo is the early stage of development of a multicellular organism A multicellular organism is an organism that consists of mor ...
, in the midline, called the copula linguae, 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). 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. 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 Tongue#Upper surface of the tongue, foramen cecum, which is the point of attachment of the thyroglossal duct where the embryonic thyroid begins to descend.


Function


Taste

Chemicals that stimulate taste receptor cells are known as Gustatory cortex#Tastant concentration-dependent neuronal activity, tastants. Once a tastant is dissolved in
saliva Saliva (commonly referred to as spit) is an extracellular fluid In cell biology Cell biology (also cellular biology or cytology) is a branch of biology Biology is the natural science that studies life and living organisms, including t ...
, it can make contact with the plasma membrane of the gustatory hairs, which are the sites of taste transduction (physiology), transduction. The tongue is equipped with many
taste buds Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as lingual papillae, papillae found on the upper surface of the tongue, soft palate, upper e ...

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. Umami receptor cells are the least understood and accordingly are the type most intensively under research.


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.


Speech

The intrinsic muscles of the tongue enable the shaping of the tongue which facilitates
speech Speech is human vocal communication Communication (from Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''c ...

speech
.


Intimacy

The tongue plays a role in physical intimacy and human sexuality, 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. The tongue can be used for stimulating the clitoris and other areas of the vulva.


Clinical significance


Disease

A congenital disorder of the tongue is that of ankyloglossia also known as ''tongue-tie''. The tongue is ''tied'' to the floor of the mouth by a very short and thickened Frenulum of tongue, frenulum and this affects speech, eating, and swallowing. The tongue is prone to several pathology, pathologies including glossitis and other inflammations such as geographic tongue, and median rhomboid glossitis; burning mouth syndrome, oral hairy leukoplakia, oral candidiasis (thrush), black hairy tongue and fissured tongue. There are several types of oral cancer that mainly affect the tongue. Mostly these are squamous cell carcinomas. Food debris, desquamation, desquamated epithelium, epithelial cells and bacteria often form a visible tongue coating. This coating has been identified as a major factor contributing to bad breath (halitosis), which can be managed by using a tongue cleaner.


Medication delivery

The sublingual region underneath the front of the tongue is an ideal location for the route of administration, administration of certain medications into the body. The oral mucosa is very thin underneath the tongue, and is underlain by a plexus of veins. 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) of Glyceryl trinitrate (pharmacology), nitroglycerin to a patient suffering chest pain from angina pectoris.


Other animals

The muscles of the tongue evolved in amphibians from occipital bone, occipital somites. Most amphibians show a proper tongue after their metamorphosis. As a consequence most vertebrate animals—amphibians, reptiles, birds, and mammals—have tongues (the frog family of Pipidae, pipids lack tongue). In mammals such as dogs and cats, the tongue is often used to clean the fur and body by licking. The tongues of these species have a very rough texture which allows them to remove oils and parasites. Some dogs have a tendency to consistently lick a part of their foreleg which can result in a cutaneous condition, skin condition known as a lick granuloma. 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. Some animals have tongues that are specially adapted for catching prey. For example, chameleons, frogs, pangolins and anteaters have prehensility, prehensile tongues. 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. 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 Tetrapods (; ) are four-limbed animals constituting the superclass Tetrapoda (). It includes extant Extant is the opposite of the word extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a sp ...
s.


Society and culture


Figures of speech

The tongue can be used as a metonymy, metonym for ''language''. For example, the New Testament of the Bible, in the Book of Acts of the Apostles, Jesus' disciples on the Day of Pentecost received a type of spiritual gift: "there appeared unto them cloven tongues like as of fire, and it sat upon each of them. And they were all filled with the Holy Ghost, and began to speak with other tongues ....", which amazed the crowd of Jewish people in Jerusalem, who were from various parts of the Roman Empire but could now understand what was being preached. The phrase ''mother tongue'' is used as a child's first language. Many languages 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 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. The "gift of tongues" refers to when one is uncommonly gifted to be able to speak in a foreign language, often as a type of spiritual gift. 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 .


Gestures

Sticking one's tongue out at someone is considered a childish gesture of rudeness 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. 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.


Body art

Tongue piercing and tongue splitting, splitting have become more common in western countries in recent decades. In one study, one-fifth of young adults were found to have at least one type of oral piercing, most commonly the tongue.


As food

The tongues of some animals are consumed and sometimes considered delicacies. Hot tongue sandwiches are frequently found on menus in kashrut, kosher delicatessens 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.


Additional images

File:Tongue.agr.jpg, The human tongue File:Spots on the tongue.jpg, Spots on the tongue File:زبان.jpg, Exclusive Lines on the tongue File:Okapitongue.jpg, An okapi cleaning its snout, muzzle with its tongue. File:Gähnende, liegende graue Katze.jpg , A cat displaying its comb-like tongue. File:Mouth illustration-Otis Archives.jpg, Medical illustration of a human mouth by Duncan Kenneth Winter File:Dog tongue.png, Distended dog tongue acting as a heat regulator


See also

* Electronic tongue * Tongue map * Vocal tract


References


External links


University of Manitoba, Anatomy of the Vocal Tract
{{Portal bar, Anatomy Tongue, Sensory organs Gustatory system Digestive system Human mouth anatomy Speech organs