Difference between revisions of "Tongue - Anatomy & Physiology"

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<big><center>[[Alimentary - Anatomy & Physiology|'''BACK TO ALIMENTARY - ANATOMY & PHYSIOLOGY''']]</center></big>
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==Introduction==
 
==Introduction==
  
The tongue (lingua) occupies the ventral aspect of the [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]] and [[Oral Cavity - Oropharynx - Anatomy & Physiology|oropharynx]]. Itis involved with grooming, lapping, prehension and manipultaing food in [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]]. It is also involved in the [[Deglutition|deglutition]] reflex and vocalisation.
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The tongue (lingua) occupies the ventral aspect of the [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]] and [[Oropharynx - Anatomy & Physiology|oropharynx]]. It is involved with grooming, lapping, prehension and manipulating food in the [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]]. It is also involved in the [[Deglutition|deglutition]] reflex and vocalisation. The tongue is capable of vigorous and precise movements due to the apex being free of attachments to the [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]].
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[[Image:Tongue Anatomy Cow.jpg|thumb|right|250px|Tongue Anatomy (Cow) - Copyright Nottingham 2008]]
  
The tongue is capable of vigerous and precise movements due to the apex being free of attachments to the [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]].
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==Structure and Function==
  
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The tongue is skeletal muscle dorsally and structural fat surrounded by a cartilagenous sheath forming lyssa (canids only) ventrally. It has an attached root and body with a free apex. The '''frenulum''' (fold of mucosa) attaches the body of the tongue to the floor of the [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]]. The root of tongue is attached to the [[Hyoid Apparatus - Anatomy & Physiology|hyoid bone]]. In the horse and dog, the tongue is 'u' shaped, becoming broader towards the tip. The furrow in the centre of the canid tongue is called the '''median sulcus'''. In the ox, sheep and pig the tongue is 'v' shaped with a pointed apex. The '''torus linguae''' is a swelling across the tongue laterally which pushes food against the [[Hard Palate|hard palate]].
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[[Image:Tongue Anatomy Cow2.jpg|thumb|right|250px|Tongue Anatomy (Cow) - Copyright Nottingham 2008]]
  
==Functional Anatomy==
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==Muscles==
 
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[[Image:Tongue Venous Drainage.jpg|thumb|right|250px|Venous Drainage of the Tongue - Copyright Prof. Pat Mccarthy]]
*Skeletal muscle dorsally
 
 
 
*Structural fat surrounded by cartilagenous sheath forming lyssa (canids only) ventrally
 
 
 
*Attached root and body with a free apex
 
 
 
*Frenulum (fold of mucosa) attaches the body of the tongue to the floor of the [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]]
 
 
 
*Root of tongue attached to hyoid bone
 
  
*In the horse and dog the tongue is 'u' shaped, becoming broader towards the tip. The furrow in the centre of the canid tongue is called the median sulcus.
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===Intrinsic Muscles===
  
*In the ox, sheep and pig the tongue if 'v' shaped with a pointed apex. The tonus linguae is a swelling across the tongue laterally which pushes food against the [[Hard Palate - Anatomy & Physiology|hard palate]].
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Intrinsic muscles include the dorsal and ventral longitudinal muscles and the transverse and vertical bundles.  
  
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===Extrinsic Muscles===
  
==Muscles==
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The extrinsic muscles include:
  
'''Intrinsic Muscles'''
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'''Styloglossus'''
  
*The dorsal and ventral longitudinal
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Its origin is at the [[Hyoid Apparatus - Anatomy & Physiology|hyoid apparatus]] (stylohyoid) and it retracts and elevates the tongue.
  
* Transverse and vertical bundles
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'''Genioglossus'''
  
'''Extrinsic Muscles'''
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The origin is at the incisive part of the [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]]. It protrudes and depressed the tongue.
  
*Styloglossus
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'''Hyoglossus'''
    -Origin: Hyoid apparatus (stylohyoid)
 
    -Retracts and elevates tongue
 
  
*Genioglossus
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The origin is at the [[Hyoid Apparatus - Anatomy & Physiology|hyoid apparatus]] (basihyoid). It retracts and depresses the tongue.
    -Origin: Incisive part of mandible
 
    -Protrudes and depressed tongue
 
  
*Hyoglossus
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'''Geniohyoideus'''
    -Origin: Hyoid apparatus (basihyoid)
 
    -Retracts and depresses tongue
 
  
*Geniohyoideus
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It originates at the incisive part of the [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]] and the insertion site is the body of the [[Hyoid Apparatus - Anatomy & Physiology|hyoid]]. It lies below the tongue (not within it) and draws the [[Hyoid Apparatus - Anatomy & Physiology|hyoid]] and therefore the tongue forward.
    -Origin: Incisive part of mandible
 
    -Insertion: Body of hyoid
 
    -Lies below the tongue (not within it)
 
    -Draws the hyoid and therefore the tongue forward
 
  
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[[Image:Tongue Muscles Drawing.jpg|thumb|right|250px|Drawing of the Extrinsic Muscles of the Tongue - Copyright nabrown]]
  
 
==Innervation==
 
==Innervation==
  
*All muscles moving the tongue are innervated by the hypoglossal nerve (CN XII)
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All muscles moving the tongue are innervated by the hypoglossal nerve ([[Cranial Nerves - Anatomy & Physiology|CN XII]]). The rostral 2/3 of the tongue is innervated by the sensory lingual branch of the trigeminal ([[Cranial Nerves - Anatomy & Physiology|CN V]]) transmitting temperature, touch and pain sensation. The chorda tympani of the facial nerve ([[Cranial Nerves - Anatomy & Physiology|CN VII]]) transmits the taste. The caudal 1/3 of the tongue is innervated by the glossopharyngeal ([[Cranial Nerves - Anatomy & Physiology|CN IX]]) providing sensory function for taste.
 
 
*Rostral 2/3 of tongue is innervated by the lingual branch of trigeminal (CN V) which is sensory supplying temperature, touch and pain. The Chorda tympani of facial (CN VII) supplies the taste.
 
 
 
*The caudal 1/3 of tongue is innervated by the glossopharyngeal (CN IX) providing motor function for taste.
 
  
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==Vasculature==
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The main blood supply to the tongue is via the '''lingual artery''', a branch of the external carotid artery. A secondary blood supply to the tongue is provided via the tonsillar branch of the facial artery and the ascending pharyngeal artery.
  
 
==Histology==
 
==Histology==
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[[Image:Tongue Histology Cat.jpg|thumb|right|250px|Tongue Histology (Cat) - Copyright RVC 2008]]
  
*Stratified squamous epithelium
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The tongue consists of stratified squamous epithelium. There are [[Lingual Gland - Anatomy & Physiology|lingual]] glands and a mucosal covering tightly adheres to the contact surface. The degree of keratinisation depends on the diet. There is less keratinisation on the ventral surface and sides of tongue. It is covered by papillae for protection and taste. Papillae are specialised projections of the mucosa. Some papillae have taste buds, others are mechanical to roughen the surface of the tongue.
 
 
*Lingual glands
 
 
 
*Mucosal covering tightly adheres to the contact surface
 
 
 
*Degree of keratinisation depends on diet
 
 
 
*Less keratinisation on ventral surface and sides of tongue
 
 
 
*Covered by papillae (taste buds)for protection and taste
 
 
 
*Papillae are specialised projections of the mucosa
 
 
 
*Some papillae have taste buds others are mechanical to roughen surface of tongue
 
 
 
  
 
==Types of Papillae==
 
==Types of Papillae==
  
*Conical
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===Conical===
    -Not in horses
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Conical papillae are not found in horses. They are present in the caudal 1/3 of the tongue. They point caudally and have no taste buds. There is a thick epithelium.
    -Caudal 1/3 of tongue
 
    -Point caudally
 
    -No taste buds
 
    -Thick epithelium
 
  
*Foliate
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[[Image:Foliate_Papillae_Cat.jpg|thumb|right|250px|Foliate Papillae (Cat) - Copyright RVC 2008]]
    -8 to 12 papillae in group, one either side of tongue midline
 
    -Stratified squamous epithelium
 
    -Caudal 1/3 of tongue
 
    -Taste buds present
 
  
*Vallate
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===Foliate===
    -3 to 6
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Eight to twelve papillae in parallel folds, one either side of the tongue midline. Consists of a stratified squamous epithelium, present in the caudal third of the tongue. There are taste buds, glands and lymphatics present.
    -Often secondary papillae in taste buds
 
    -Broad glands
 
    -Caudal 1/3 of tongue
 
    -Taste buds present
 
  
*Fungiform
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===Vallate===
    -Red dots on tongue surface
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[[Image:Circumvallate Papillae.jpg|thumb|right|250px|Circumvallate Papillae (Goat) - Copyright RVC 2008]]
    -Keratinised, stratified squamous epithelium
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There are three to six, often secondary papillae in taste buds. There are broad glands in the caudal 1/3 of tongue. Taste buds and lymphatics are present.
    -Blood vessels
 
    -Loss of heat via panting in dogs
 
    -Rostral 2/3 of tongue
 
    -Taste buds present
 
  
*Filoform
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===Fungiform===
    -Most numerous
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They form the red dots on tongue surface and consist of keratinised, stratified squamous epithelium and blood vessels. They are involved in loss of heat via panting in dogs. They are present in the rostral 2/3 of the tongue and contain taste buds.
    -Points caudally
 
    -No taste buds
 
    -Smallest
 
    -Thick epithelium
 
    -Very prominent in cat
 
    -Rostral 2/3 of tongue
 
  
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[[Image:Filoform Papillae Histology.jpg|thumb|right|250px|Filoform Papillae Histology (Cat) - Copyright RVC 2008]]
  
==Taste Buds==
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===Filiform===
 +
Filiform papillae are the most numerous and point caudally. There are no taste buds, glands or lymphatics. They are the smallest and consist of a thick keratin on stratified squamous epithelium. They are very prominent in cat and are present in the rostral 2/3 of the tongue.
  
*Also found on the [[Soft Palate - Anatomy & Physiology|soft palate]] and pharynx (but sparsely distributed)
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==[[Gustatory System - Anatomy & Physiology|Taste Buds]]==
 
 
*Constant cell turnover
 
 
 
*Flat, think cells
 
 
 
*Taste hairs (microvilli) pointing though taste pore
 
 
 
*Nerves transduce chemical signals into nervous signals
 
  
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Also found on the [[Soft Palate|soft palate]] and the [[Pharynx - Anatomy & Physiology|pharynx]] (but sparsely distributed). There is a constant cell turnover, with flat, thick cells. There are taste hairs (microvilli) pointing through the taste pore. Nerves transduce chemical signals into nervous signals.
  
 
==Species Differences==
 
==Species Differences==
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[[Image:Pig Tongue.jpg|thumb|right|250px|''Pig Tongue'' <br> Pollo 2007, WikiMedia Commons]]
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===Canine===
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There are stretch receptors in the tongue and they use the tongue to lose heat by panting.
  
*Dog has stretch receptors in the tongue
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===Ruminant===
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The tongue is heavily keratinised with long papillae for eating (protective surface). The ox has lenticular papillae which are hard and horny due to heavy keratinisation.
  
*Dog uses the tongue to lose heat by panting
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===Feline===
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Feline species have long papillae for grooming, so their tongue is rough.
  
*Ruminant tongue is heavily keratinised with long papillae for eating (protective surface)
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===Porcine===
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Most of the papillae are soft, long and directed caudally.
  
*Cat has long papillae for grooming so tongue is rough
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===[[Avian Tongue - Anatomy & Physiology|Avian]] ===
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The avian tongue contains a bone and is mainly used for manipulation of food rather than vocalisation like in mammals. Parrots use the tongue to produce human sounds (see [[Syrinx - Anatomy & Physiology#Species differences|species differences in syrinx]])
  
*Ox has lenticular papillae which are hard and horny due to heavy keratinisation
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==Links==
 
 
*Most of the papillae in the pig are soft, long and directed caudally
 
 
 
*The avian tongue has a bone in it. It is mainly used for manipulation of food rather than vocalisation like in mammals.
 
  
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Click here for [[Tongue - Pathology|pathology of the tongue]] information.
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<br>
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{{Learning
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|flashcards= [[Tongue Anatomy & Physiology Flashcards]]<br>[[Facial_Muscles_-_Musculoskeletal_-_Flashcards|Facial Muscles]]
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|powerpoints= [[Oral Cavity Histology resource|Histology of the oral cavity, see part 1 for the tongue]]
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|videos = [[Video: Ventral muscles of the head potcast|Ventral muscles of the head potcast]]<br>[[Video: Lateral surface of the head of the dog potcast|Lateral surface of the head of the dog potcast]]<br>[[Video: Lateral surface and sagittal section of the head of a sheep|Lateral surface and sagittal section of the head of a sheep]]<br>[[Video: Lateral surface of the head of the dog potcast 5|Lateral surface of the head of the dog potcast 5]]
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|OVAM = [http://www.onlineveterinaryanatomy.net/content/cat-tongue Image - Cat Tongue]
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|Vetstream = [https://www.vetstream.com/canis/Content/Disease/dis00702.asp Macroglossia]
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}}
  
==Links==
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==Webinars==
 
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<rss max="10" highlight="none">https://www.thewebinarvet.com/gastroenterology-and-nutrition/webinars/feed</rss>
[[Oral Cavity - Cavity & Gingiva|Glossitis- inflammation of the tongue]]
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[[Category:Oral Cavity - Anatomy & Physiology]]

Latest revision as of 19:19, 27 October 2022


Introduction

The tongue (lingua) occupies the ventral aspect of the oral cavity and oropharynx. It is involved with grooming, lapping, prehension and manipulating food in the oral cavity. It is also involved in the deglutition reflex and vocalisation. The tongue is capable of vigorous and precise movements due to the apex being free of attachments to the oral cavity.

Tongue Anatomy (Cow) - Copyright Nottingham 2008

Structure and Function

The tongue is skeletal muscle dorsally and structural fat surrounded by a cartilagenous sheath forming lyssa (canids only) ventrally. It has an attached root and body with a free apex. The frenulum (fold of mucosa) attaches the body of the tongue to the floor of the oral cavity. The root of tongue is attached to the hyoid bone. In the horse and dog, the tongue is 'u' shaped, becoming broader towards the tip. The furrow in the centre of the canid tongue is called the median sulcus. In the ox, sheep and pig the tongue is 'v' shaped with a pointed apex. The torus linguae is a swelling across the tongue laterally which pushes food against the hard palate.

Tongue Anatomy (Cow) - Copyright Nottingham 2008

Muscles

Venous Drainage of the Tongue - Copyright Prof. Pat Mccarthy

Intrinsic Muscles

Intrinsic muscles include the dorsal and ventral longitudinal muscles and the transverse and vertical bundles.

Extrinsic Muscles

The extrinsic muscles include:

Styloglossus

Its origin is at the hyoid apparatus (stylohyoid) and it retracts and elevates the tongue.

Genioglossus

The origin is at the incisive part of the mandible. It protrudes and depressed the tongue.

Hyoglossus

The origin is at the hyoid apparatus (basihyoid). It retracts and depresses the tongue.

Geniohyoideus

It originates at the incisive part of the mandible and the insertion site is the body of the hyoid. It lies below the tongue (not within it) and draws the hyoid and therefore the tongue forward.

Drawing of the Extrinsic Muscles of the Tongue - Copyright nabrown

Innervation

All muscles moving the tongue are innervated by the hypoglossal nerve (CN XII). The rostral 2/3 of the tongue is innervated by the sensory lingual branch of the trigeminal (CN V) transmitting temperature, touch and pain sensation. The chorda tympani of the facial nerve (CN VII) transmits the taste. The caudal 1/3 of the tongue is innervated by the glossopharyngeal (CN IX) providing sensory function for taste.

Vasculature

The main blood supply to the tongue is via the lingual artery, a branch of the external carotid artery. A secondary blood supply to the tongue is provided via the tonsillar branch of the facial artery and the ascending pharyngeal artery.

Histology

Tongue Histology (Cat) - Copyright RVC 2008

The tongue consists of stratified squamous epithelium. There are lingual glands and a mucosal covering tightly adheres to the contact surface. The degree of keratinisation depends on the diet. There is less keratinisation on the ventral surface and sides of tongue. It is covered by papillae for protection and taste. Papillae are specialised projections of the mucosa. Some papillae have taste buds, others are mechanical to roughen the surface of the tongue.

Types of Papillae

Conical

Conical papillae are not found in horses. They are present in the caudal 1/3 of the tongue. They point caudally and have no taste buds. There is a thick epithelium.

Foliate Papillae (Cat) - Copyright RVC 2008

Foliate

Eight to twelve papillae in parallel folds, one either side of the tongue midline. Consists of a stratified squamous epithelium, present in the caudal third of the tongue. There are taste buds, glands and lymphatics present.

Vallate

Circumvallate Papillae (Goat) - Copyright RVC 2008

There are three to six, often secondary papillae in taste buds. There are broad glands in the caudal 1/3 of tongue. Taste buds and lymphatics are present.

Fungiform

They form the red dots on tongue surface and consist of keratinised, stratified squamous epithelium and blood vessels. They are involved in loss of heat via panting in dogs. They are present in the rostral 2/3 of the tongue and contain taste buds.

Filoform Papillae Histology (Cat) - Copyright RVC 2008

Filiform

Filiform papillae are the most numerous and point caudally. There are no taste buds, glands or lymphatics. They are the smallest and consist of a thick keratin on stratified squamous epithelium. They are very prominent in cat and are present in the rostral 2/3 of the tongue.

Taste Buds

Also found on the soft palate and the pharynx (but sparsely distributed). There is a constant cell turnover, with flat, thick cells. There are taste hairs (microvilli) pointing through the taste pore. Nerves transduce chemical signals into nervous signals.

Species Differences

Pig Tongue
Pollo 2007, WikiMedia Commons

Canine

There are stretch receptors in the tongue and they use the tongue to lose heat by panting.

Ruminant

The tongue is heavily keratinised with long papillae for eating (protective surface). The ox has lenticular papillae which are hard and horny due to heavy keratinisation.

Feline

Feline species have long papillae for grooming, so their tongue is rough.

Porcine

Most of the papillae are soft, long and directed caudally.

Avian

The avian tongue contains a bone and is mainly used for manipulation of food rather than vocalisation like in mammals. Parrots use the tongue to produce human sounds (see species differences in syrinx)

Links

Click here for pathology of the tongue information.

Tongue - Anatomy & Physiology Learning Resources
VetstreamVetlexicon advert button.png
Vetstream
To reach the Vetstream content, please select
Canis, Felis, Lapis or Equis
FlashcardsFlashcards logo.png
Flashcards
Test your knowledge using flashcard type questions
Tongue Anatomy & Physiology Flashcards
Facial Muscles
VideoWikiVideo.png
Videos
Selection of relevant videos
Ventral muscles of the head potcast
Lateral surface of the head of the dog potcast
Lateral surface and sagittal section of the head of a sheep
Lateral surface of the head of the dog potcast 5
Category:Histology PowerPointsPowerPoint.png
PowerPoint
Selection of relevant PowerPoint tutorials
Histology of the oral cavity, see part 1 for the tongue
OVAMOVAM-no text.png
OVAM
Anatomy Museum Resources
Image - Cat Tongue


Webinars

Failed to load RSS feed from https://www.thewebinarvet.com/gastroenterology-and-nutrition/webinars/feed: Error parsing XML for RSS