Functions of tongue : deglutition, taste sensation, speech, mastication
Blood Supply
●Tongue is mainly supplied by lingual artery branchof external carotid artery, tonsilar branch of facial artery and Ascending pharyngeal artery branch of external carotid artery
● Venous drainage : dorsal lingual veins and deep lingual veins
● Sensory supply: lingual nerve supplies anterior 2/3rd of tongue, glossopharngeal nerve supplies posterior 1/3rd of tongue, Vagus nerve supplies posterior most part of tongue
● Motor supply : All extrinsic and intrinsic muscles of the tongue are supplied by hypoglossal nerve except palatoglossus supplied by vagus nerve
Clinical significance
● Ankyloglossia (tongue tie) : Occurs due to abnormal length of frenulum that extends to the tip of the tongue . Ankyloglossia can be corrected surgically.
● Fissured tongue: Occurs when small furrows present on dorsal surface of the tongue. They are generally painless and benign and often associated with other syndromes
● Geographic tongue: asymptomatic and benign characterized by presence of red patches with greyish white border covering dorsum of tongue
Interesting facts
● An average adult has 2000- 4000 taste buds
● You cannot see your taste buds with naked eye. Those tiny pink and white bumps you see are actually papillae
● Tongue muscles are only muscles in the body working independent of the skeleton
● An oversized tongue is indicative of sleep apnea disorder
● Children sense flavours more intensely compared to adults. Umami is new variant of taste , monosodium glutamate is chemical responsible for this taste
● Women have shorter tongue than men.
● Your tongue is germ free only of its pink. If it is white there is a thin film of bacteria on it
● Blue whale has largest tongue in animal kingdom and weighs 5400lbs
Reference: B.D chaurasia and interesting facts from google
● Tongue is the muscular organ situated in the floor of the mouth
It has 2 surfaces
• Superior surface
• Inferior surface
● Superior surface is divided into 3 parts Anterior 2/3rd or oral part , posterior 1/3rd or pharyngeal part and base or root of the tongue
● Anterior 2/3rd and posterior 1/3rd are divided by V shaped sulcus terminalis, they are structurally and developmentally distinct.
● Inferior surface is covered by smooth mucous membrane. In midline a mucosal fold called frenulum connects tongue with floor of the mouth
● Lateral to frenulum deep lingual veins can be seen through mucosa lateral to lingual vein , mucosal fold called plica fimbriata is present
PAPILLAE OF TONGUE
Superior surface of tongue contains numerous papillae and have taste buds on their surface
Types of papillae
• Circumvalate papillae : present in front of sulcus terminalis , largest among papillae 8 to 12 in number
• Filliform papillae : Thin, long papillae with pointed ends. No taste buds. Identified by keratinization.
• Fungiform papillae: Slightly mushroom shaped , larger than Filliform papillae and present at apex of tongue and margins
• Foliate papillae : short vertical folds , present lateral to terminal sulcus and at margins
TASTE BUDS
Taste buds are sensory receptors for taste. Sensation of taste is called gustation. Taste buds are located on surface of all papillae except Filliform papillae
Four taste sensation are sour, sweet, salty, bitter and recently added is umami
MUSCLES OF TONGUE
● Intrinsic muscles: Main function is to alter the shape of the tongue ,they originate and insert within the tongue and no bony attachments. ( 4) superior longitudinal, inferior longitudinal, vertical and transverse muscles
● Extrinsic muscles : These muscles take origin from outside of the tongue and alter the shape as well.(4) Genioglossus, hyoglossus, styloglossus and palatoglossus
Superior longitudinal muscle: It lies just beneath dorsum of tongue. Action: It curls the tip upward and roll it posteriorly
Inferior longitudinal muscle : lies on each side lateral to the Genioglossus muscle. Action : To curl the tip of the tongue inferiorly
Transverse muscle: lies inferior to the superior longitudinal muscle and run from the septum to margins. Action : They narrow the tongue and increase the height
Vertical muscle: It lies inferolaterally to the Dorsum of tongue. Action : flattens the Dorsum
Genioglossus : origin- from superior mental spine and gets inserted into mucous membrane of tongue. It’s action is to protrude tongue, depress central part of tongue and increase the volume of sucking
Hyoglossus : origin- from greater horn and body of hyped bone and gets inserted to side of the tongue. It’s action is to depress side of the tongue assisting Genioglossus to enlarge the oral cavity
Styloglossus : origin- lower part of styloid process and upper part of stylohyoid ligament and inserts on side of the tongue. Action is to elevate and retract the tongue
Palatoglossus : origin- from soft palate and insertion lateral margin of tongue
♢ Styloglossus and palatoglossus attach the tongue Superiorly ,while Genioglossus and hyoglossus attached to the tongue inferiorly
♢ All the extrinsic and intrinsic muscles of tongue are supplied by hypoglossal nerve except palatoglossus supplied by vagus nerve
• Types of giant cells - grossly classified into 2 types. – • The giant cells which exist in normal tissue (physiological) e.g osteoclasts in bones, trophoblasts in placenta, odontoclast, straited muscle.
• The giant cells which exist pathological -eg. Foreign body giant cells Langhan's giant cells Touton giant cells Aschoff giant cells Anaplastic cancer giant cells Reed-Sternberg giant cells
Curated by: Dr. Tabassum Sayyad (Dental Intern – MARDC)
Cytokines are soluble protiens/polypeptides, produces by a variety of hematopoetic and non hematopoetic cell types. They are responsible for the regulation of immunological, inflammatory and reparative host responses.
Cytokines tend to bind to high affinity receptors and the target cells and mediate their effects. Specific cytokines mediate specific reactions.
Reference: Arvind Arora
Cytokines basically mediate immune response. But some cytokines are also pro inflammatory.
These are:-
Il-1, TNF alpha and IL-6.
IL-1 is the most important pro inflammatory cytokine.
Anti inflammatory cytokines are involved in the resolution of inflammation. These include:
IL-4, IL-10 IL-13 and TGF beta.
IL-4 has mainly anti-inflammatory properties with some pro-inflammatory properties.
• Baroodontalgia refers to baro- pressure odonto – teeth Algia- pain. It’s also called as Aerodontalgia or flyers tooth or tooth squeeze
• It is the pain in the teeth caused due to changes in pressure which may be seen in case of high altitude as seen in pilots and in deep sea divers who also see severe changes in pressure which lead to pain in the tooth.
• Baroodontalgia is usually seen in teeth which have pre existing dental pathology or have improper dental treatments such as chronic pulpitis is the primary culprit; Restored teeth are more likely to be involved ; Maxillary sinusitis; Improper fillings Carious teeth and periapical cysts
• Note that normal teeth without any underlying pathologies are not affected by any change in pressure.
• Baroodontalgia occurs during initial pressure from 14.7psi to 12- 18 psi.
Why there is pain in tooth due to pressure change?
• Due to change in external pressure there will be expansion of gas with compensatory increase in pressure within the pulp chamber and root canal of the tooth which is defective due to any underlying pathology
• Direct pressure in the exposed nerve endings and microleakage of Restorative material from a faulty restoration
• pain is most seen in maxillary posteriors and results from compromised blood supply to the tooth
• In pulpitis – pain on ascent and relief on descent and in Necrosis – pain on decent and relief on ascent
TREATMENT :
– Hyperbaric oxygen therapy is the treatment to avoid baroodontalgia where the person is put in a 100% compressed oxygen chamber which prepares the body for high pressures and compression
– Identification of underlying dental pathology and getting treated properly.
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