This document summarizes the specialized mucosa and papillae found on the dorsal surface of the tongue. It describes the four main types of papillae - filliform, fungiform, circumvallate, and foliate papillae. It details their locations, histological features, and functions. The document also discusses taste buds and their role in gustation. Finally, it covers the clinical significance of some variations in tongue morphology and the differences seen in other species.

1. Dr. Meera K Pynadath
Dept. Oral Pathology &
Microbiology
Royal Dental College
Specialized Mucosa

2. Specialized mucosa
 Dorsum of tongue / dorsolingual mucosa
 Taste buds – sensory function
 “Sensory Mucosa”
 Dorsum of tongue – 2 parts
 Separated by sulcus terminalis
1. Anterior 2/3rd – papillary portion
2. Posterior 1/3rd – lymphatic portion

3. PAPPILLAE
 Fine papillary projections seen on dorsum and
lateral borders of tongue
 4 types:
1. Filliform (most numerous)
2. Fungiform
3. Circumvalate
4. Foliate
 Different functions – Rough texture and taste
sensation

4. Filliform papillae
 Most numerous
 Location: Anterior 2/3rd of
dorsolingual mucosa.
 Meaning : Filament like or thread
like
 Macroscopic structure:
 Numerous fine, pointed & cone
shaped projections
 “velvet appearance”
 No taste buds
 Functions:
1. Characteristic rough texture
2. Increase surface area & friction of
tongue – manipulate food bolus.
3. Sensation of touch

5. Histology of filliform
 Epithelial structures with
connective tissue core.
 Epithelium – Keratinised
stratified squamous.
 Keratin forms tufts at the apex of
papilla
 Connective tissue core – lamina
propria.
 Secondary pappillary
projection into epithelium

6. Fungiform papillae
 Location : Anterior 2/3rd
 Interspersed between filliform papillae
 Predominantly on tip and sides
 Meaning: “mushroom shape”
 Macroscopic structure:
 Round, reddish prominences
 Microscopic features
 Non keratinized
 Connective tissue core
 Rich vascular supply in lamina propria
 Dorsal portion – taste buds (1 to 3
nos)

7. Circumvalate papillae
 Also called valate papillae
 Location: Arranged anteriorly to sulcus
terminalis
 In a single row
 Number: 8 to 10
 Meaning : “surrounded by wall”
 Structure:
 Do not protrude to surface
 Dome shape
 Broader dorsal surface
 Narrow base
 Surrounded by deep circular
furrow/trough
 Trough surrounded elevated wall of
mucosa - vallum

8. Histology
 Stratified squamous epithelium
 Thin epithelium and larger CT core
 Epithelium shows secondary papillae of
connective tissue
 Superficial surface – keratinised
 Lateral surface – non keratinised
 Lateral aspects – taste buds
 Beneath the trough – von Ebner’s gland
open.
 Serous secretion clear the trough
 Contain salivary lipase.

9. Folliate Papillae
 Location: small vertical folds on lateral
border of posterior tongue
 Contain 4 to 11 parallel ridges.
 Meaning: Leaf like shape.
 Rudimentary in humans
 Contains taste buds

10. Taste buds
 Intraepithelial organs contain taste receptor cells or gustatory
cells
 Chemosensory - Responsible for taste sensation or gustation
 Detect 5 elements – sweet, sour, salt, bitter and umami
 Number: 4000 in oral cavity & upper ailmentary canal.
 Location: Seen papillae of tongue, soft palate, buccal mucosa,
epiglottis and esophagus.
 75% in oral cavity – 50% valate, 25% fungiform, and 25% folliate

11. Structure
 Shape: barrel or ovoid
 Size: 80µm high and 40µm thick
 Intraepithelial – from basal lamina to
the surface of the epithelium.
 Taste pore: outer opening of taste
(more than 1)
 Cells:
 Each tastebud has – 50 to 100
specialised cells.
1. Outer supporting cells –
 Outer longer cells -staves of barrel
 Inner shorter cells – spindle shape
2. Inner neuroepithelial cells –
receptor for taste stimuli (10 – 12
nos)
 Slender, dark staining cells, finger
like projections towards taste pore

12. Ultrastructural
findings
 4 cell types:
 Type I – dark cells –long cells- microvilli and
numerous vessicles related to gustatory nvs
 Type II– light cells- oval shape
 Type III- intermediate cells-light cells
 Type IV-rest on basement membrane,
precursor – undifferentiated cells.

13. Regions of taste
•Fungiform : sweet and salty
• Circum valate : bitter
•Foliate : sour
First concept
Second concept:
Taste cannot be broken down into areas
Taste is based on range of stimuli by chemical
substances in the food that fire up the gustatory nerves.
Taste is a continuum or total response of many gustatory
nerves

14. Posterior 1/3 rd of tongue
 Irregular studded cells with
numerous rounded or oval
prominence – Lingual
follicles
 Comprises of :
 lymph nodules with germinal
centers
 Lingual crypt on surface –
 lymphocytes migrate into
crypt through epithelium.
 Ducts of small posterior
lingual mucous glands opens
into crypt
 Lingual tonsil

15. Clinical significance
1. Depapillation
 Lingual papilla is lost
leaving a smooth, red
and painfull areas.
 Median rhomboid
glossitis and benign
migratory glossitis
(geographic tongue).
 Systemic diseases –iron
deficiency, pernicious
aneamia and vitamin
deficiency, vitamin B
complex deficiency – beefy
red tongue.
 Infections – scarlet fever
 Strawberry or raspberry
tongue

16.  Hairy tongue :
 Defective desquamation of
filliform papillae
 Hypertrophy of filliform
papillae.
 Normal papilla – 1mm
 Hairy tongue – 15 mm.
 Reasons:
 Lack mechanical debridement
and oral hygiene
 Tobacco use etc.
 Symptoms & signs:
 Tickling sensation esp palate
 Halitosis
 Burning sensation

17. Variation in other species

18. End session