Specialized Mucosa.pptx

Specialized Mucosa Dr.Meera K Pynadath

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 Anterior 2/3 rd – papillary portion Posterior 1/3 rd – lymphatic portion

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

4. Filliform papillae Most numerous Location: Anterior 2/3 rd of dorsolingual mucosa. Meaning : Filament like or thread like Macroscopic structure: Numerous fine, pointed & cone shaped projections “velvet appearance” No taste buds Functions: Characteristic rough texture Increase surface area & friction of tongue – manipulate food bolus. 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 2/3 rd 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. Outer supporting cells – Outer longer cells -staves of barrel Inner shorter cells – spindle shape 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 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

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