1. Vermilion zone:
Transitional zone b/n skin & mucous membrane
Found only in humans
Skin – thick, keratinised epithelium.
Blood is visible through the thin parts of the translucent epithelium that
gives the red color.

2. Tongue:
 surface is rough & irregular.
 body / A 2/3 base/ P 1/3
Develop from different visceral arches.
Lingual nerve glossopharyngeal N
Papillary lymphatic
Filiform papillae:
Numerous fine pointed, cone shaped – velvet like appearance
Keratinised
No taste buds

3. Fungiform papillae:
Mushroom shaped
Interpersed b/n filiform papillae
2-3 taste buds
Circumvillate papillae:
V- shaped terminal sulcus, b/n body & base
8-10 no
Numerous taste buds
Foliate papillae:
Posterior lateral surface
Presence of taste buds.

4. Taste bud:
Small. Ovoid or barrel shaped
Extend from basal lamina to the surface of the epithelium.
Outer surface - flat epithelial cells with a small opening called TASTE PORE
It forms a narrow space lined by SUPPORTING CELLS
Arranged like a staves of a barrel.
Neuroepithelial cells – receptors of taste stimuli
Primary taste sensation sweet, salty, bitter & sour.
Sweet – tip, salty- lateral border ( fungi form papillae) – chorda tympani
Bitter– middle (CP), Sour– Lateral border ( Foliate.P)– glossopharyngeal .N

5. Gingival sulcus:
Space b/n inner aspect of gingiva & tooth
Extends from free gingival margin to DGJ
Sulcular epithelium / crevicular epithelium
Normal GS depth -2mm
Periodontal disease.
DENTOGINGIVAL JUNCTION:
Junction b/n gingiva & tooth
Epithelium of gingiva gets attached to the tooth – junctional / attachment .E
The union b/n epithelium & tooth is called epithelial attachment.

6. JE- resembles REE
Development:
Ameloblast after formation of enamel matrix they leave a thin membrane
On the surface of enamel PRIMARY ENAMEL CUTICLE.
Ameloblasts cells becomes flat cuboid cells – REE
Eruption - fusion of PEC & REE.
Remnants of PEC – NASMYTH’S MEMBRANE.
Tip of crown emerged, the REE termed as PRIMARY ATTCHEMENT EPITHELIUM
Margin of gingiva the attachment epithelium is continuous with oral epithelium
Tooth erupts – REE (shorter) – forms gingival sulcus.

7. Shift of dentogingival junction:
Position of gingiva on the surface of the tooth changes with time.
Ist stage: bottom of the gingival sulcus remains enamel & apical end of
attachment epithelium at CEJ
primary teeth, 20 -30 Y
II nd stage: bottom of GS on the enamel & apical end is shifted to the
surface of cementum
Dissloution of fiber bundles that were anchored in the cervical
parts of cementum
Above 40 Y

8. IIIrd stage:
Bottom of the GS at CEJ & epithelial attachment entirely on the cementum
IV stage:
Recession of gingiva
Entire attachemnt on cementum.