this ppt describes about development of tongue

2. Tongue is a highly muscular organ of deglutition
, taste and speech ; it is partly oral and partly
pharyngeal in position.
 It is attached by its muscles to the hyoid bone ,
mandible , styloid processes ,soft palate and
pharyngeal wall.

6.  Anterior 2/3rd – from two lingual swellings
and one tuberculum impar which arises from
first branchial arch.
 Posterior1/3rd – from cranial large part of the
hypobranchial eminence i.e from the 3rd arch.
 posterior-most part - from caudal part of the
hypobranchial eminence i.e from the fourth
arch

8.  Some muscles probably differentiate in situ but
most of them are derived from myoblasts
originating in the occipital somites.
 This fact is supported by the fact that the
tongue musculature is innervated by the
hypoglossal nerve.

10. TONGUE
ROOT APEX
DORSUM
INFERIOR
SURFACE

11.  It is attached to the hyoid and mandible and
between them it is in contact inferiorly with the
geniohyoid and mylohyoid muscles.

12.  Forms anterior free
end
 At rest position– lies
behind upper incisors

13. DORSUM
Oral/presulcal part
Pharyngeal/postsulcal
part

15.  Located in the oral cavity and on its floor
 Has apex touching the incisor teeth
 Its margin is in contact with the gums & teeth
 Its superior surface (dorsum) is related to the
hard & soft palates.
 On each side ,in front of the palatoglossal arch,
are four or five verticle folds,the foliate
papillae.

16.  Lies posterior to the palatoglossal arches
 Forms the anterior wall of oropharynx
 Devoid of papillae
 Has low elevations due to lymphoid nodules
embedded in the submucosa - LINGUAL
TONSILS
 Mucous glands

17.  Connected to epiglottis by three folds
1. Median glossoepiglottic fold
2. Right lateral epiglottic fold
3. Left lateral epiglottic fold

18.  Mucosa is smooth ,purplish & reflected on to
the oral floor and gums ,being connected to
the former by the median frenulum linguae.
 Lateral to this the deep lingual vein is visible
& lateral to the vein is a fringed plica fimbriata
,directed anteromedially towards the lingual
apex.

20.  These are projections of lamina propria which
elevate the epithelium above the general level.
 Numerous in number & limited to the
presulcal part of dorsum ,producing its
characteristic roughness.

22. papillae
vallate
foliate
filliform
fungiform

23.  Large
 8-12 in number
 1-2mm in diameter
 Form a V shaped row immediately in front of
the sulcus terminalis.
 Encompassed by a circular depression of
mucosa & surrounded by a wall (vallum)
separated from the papilla by a circular sulcus

24.  Papillae is a truncated cone
 Entire structure is covered with stratified
squamous epithelium
 In both the sulcal walls taste buds are present
 Opening of ducts of Von ebner

26.  More numerous than vallate
 Occur mainly on lingual margin but also occur
irregularly on the dorsum.
 Larger than filiform papillae

27. • Round in shape and deep red in color
• Have secondary subepithelial papillae
• Bear taste buds

28.  Cover most of the presulcal dorsal area
 2-3mm long
 They are minute, conical or cylindrical
 arranged in rows parallel with the vallate
papillae except at the lingual apex where they
are tranverse.

29.  Bear many secondary papillae which are more
pointed than vallate and fungiform papillae.
 Do not bear taste buds

30.  Epithelium is keratinized ,may split into fine
processes, each being the apex of a secondary
papilla
 These are whitish owing to thickened
epithelium ,its elongated cells being
keratinized.
 Increase the friction between the tongue and
the food ,facilitating the movement of particles
by the tongue within the oral cavity.

31.  Red, leaf like projections found at the sides of
the tongue near the sulcus terminalis .
 Epithelium contains taste buds.

32.  The peripheral organs of gustation are the taste
buds ,
 composed of modified epithelial cells set in
piriform groups within the epithelia of the
tongue, soft palate, palatoglossal arches,
posterior epiglottic surface and posterior wall
of oropharynx.

33.  Sense organs for taste
 Onion like, oval, pale staining epithelial
structures
 50-70 um in length
 30-50um in width.

34. • taste pore
• 3 types of cells
1. Neuroepithelial/
receptor
2. Supporting cells
3. Basal/stem cells

36. They include:
 Sour
 Salty
 Sweet
 Bitter
SOUR TASTE: the sour taste is caused by acids, that
is more acidic the acid, the stronger becomes the
sensation.
SALTY TASTE: it is elicited by inorganic compounds
such as chlorides, sulphates, bromides, iodides etc.
The cations of these salts are mainly responsible
for the salty taste.

37. SWEET TASTE: It is not caused by any single
class of chemicals, it includes sugars, glycols,
alcohols, aldehydes, ketones, amides, esters,
amino acids, some small proteins, sulfonic
acids, halogenated acids and inorganic salts of
lead and beryllium.
BITTER TASTE : This is also not caused by any
single type of chemical agent; and almost
entirely by organic substances like long chain
organic substances that contain nitrogen and
alkaloids.

38. Recently there is a new taste sensation that has
been found; UMAMI.
 “UMAMI” is originally the Japanese word for
good taste.
 MSG(Monosodium glutamate)amino acid a
food additive produces a strong umami taste.
 It is an appetitive taste and is described as a
“savory” or “meaty” taste.
 Can be tasted in cheese and soya sauce also in
tomatoes, beans, grains.

39.  Receptor Potential:
The membrane of the taste cell, like that of other
sensory receptor cells, is negatively charged on the
inside with respect to the outside. Application of a
taste substance to the taste hairs causes partial loss
of this negative potential- that is the taste cell is
depolarized.
The decrease in potential,
within a wide range, is approximately
proportional to the concentration of the
stimulating substance. This change in potential in
the taste cell is the receptor potential for taste.

40.  Initiation of the receptor potential is by binding of the
taste chemicals to protein receptor molecules that
protrude through the villus membrane
 This in turn opens ion channels, which allow sodium
ions to enter and depolarize the cell
 Then the taste chemical is gradually washed away
from the taste villus by the saliva, which removes the
stimulus.
 The type of receptor protein in each taste villus
determines the type of taste that will elicit responses.

42. tractus solitarius,
a large number of impulses are transmitted within
the brain stem itself directly into the superior and
inferior salivatory nuclei
submandibular, sublingual and parotid glands
control the secretion of saliva during the ingestion
food.

46.  Extrinsic muscles
Genioglossus
Hyoglossus
Styloglossus
palatoglossus

47.  Intrinsic muscles
 Superior longitudinal
 Inferior longitudinal
 Transverse
 Vertical

48.  Fan shaped muscle
 Forms bulk of the tongue
 ORIGIN-
Superior part of mental spine of
mandible.
INSERTION-
Tip Dorsum of the tongue &
body of hyoid bone

49.  Upper fibres - retract the tip
 Middle fibres - depress the tongue
 Lower fibres - Brings about the forward
traction of the tongue to protrude its apex from
the mouth.
 Acting bilaterally the two muscles depress the
central part of the tongue making it concave
side to side.

52.  ORIGIN
whole length of greater cornu & the front part of
body of hyoid bone
 INSERTION
side and inferior aspect
of tongue
ACTION
Depresses And Retracts The Protruded Tongue

54.  ORIGIN
styloid process of temporal bone and stylohyoid ligament
INSERTION
side and inferior aspect of tongue
ACTION
retracts the tongue and draws it up to create a trough for
swallowing

56.  ORIGIN
palatine aponeurosis of soft
palate
INSERTION
side of tongue
ACTION
elevates posterior part of
tongue
approximates the palatoglossal
arches
closes the oropharyngeal
isthmus

57.  Superior longitudinal—
 Origin –submucous fibrous
layer & lingual septum
 Insertion – margins &
mucous membrane of
tongue
 Action – curls tip &
sides of tongue superiorly
and shortens the tongue

58.  Inferior longitudinal
 Origin -root of tongue and body of hyoid bone
Insertion – apex of tongue
 Action
- shortens the tongue
-curls the tongue inferiorly

59.  Transverse muscles—
 Origin - Extends from median septum to the
margin
 Insertion – fibrous tissue at the margins of the
tongue
 Action— narrows and elongates the tongue

60.  Vertical muscle
 Origin – superior surface of borders of
tongue
 Insertion – inferior surface of borders of
tongue
 Action- flattens and broadens the tongue

62.  The main artery is the lingual artery branch of
external carotid artery
 The tonsillar & ascending palatine branches of
the facial and ascending pharyngeal arteries
also supply the lingual root.

65.  TIP— bilaterally— submental nodes
 ANTERIOR 23rd— unilaterally— submandibular
nodes
 POSTERIOR 23rd— bilaterally— juguloomohyoid
nodes
 JUGULO-OMOHYOID NODES known as LYMPH
NODES OF THE TONGUE

67.  Injury to hypoglossal nerve paralysis of the
muscles on the side of lesion
 Glossitis
 Acute glossitis enormous swelling
 Under surface jaundice
 Unconscious patient tongue may fall back &
obstruct the air passages

68.  Gray’s anatomy 37th edition
 Langman’s medical embryology 6th edition
 Grant’s atlas of anatomy 12th edition
 Bd charausia 3rd edition
 Human embryology. Inderbir singh; 3rd edition
 Essentials of Medical Physiology-4th edition-
Sembulingam
 Tencate’s oral histology. Antoni Nanci; 3rd edition.
 Orban’s oral histology. 5th edition
 Text book of histology, G.P Pal; 2nd edition.