1. Oral mucous membrane

2. Lining Mucosa
The epithelium of lining mucosa is a non-keratinized stratified squamous epithelium, which has a:
􀁺 A basal layer
spinous layer
􀁺 An intermediate layer)
􀁺 A superficial layer
the interface between the mucosal epithelium and connective tissue is fairly "flat" compared to that in either skin or masticatory mucosa. The deeper submucosa is analagous to the hypodermis or subcutus of the skin, and it contains glands and adipose tissue.Collagen type I is the predominant fiber component of the extracellular matrix. Both collagen type III and elastic fibers are found in the lamina propria and submucosa, but their proportions vary depending on the region. Clinically, the relatively "loose" nature of the connective tissue in lining mucosa allows for the easy and relatively painless injection of local anesthetic solutions.

3. Masticatory Mucosa
In contrast to lining mucosa, masticatory mucosa has a keratinized stratified squamous epithelium:
􀁺 Basal layer
􀁺 Spinous layer
􀁺 Granular layer
􀁺 Cornified layer
Orthokeratinized -- no nuclei present
Parakeratinized -- pyknotic nuclei retained

4. The epithelial ridges and connective tissue papillae are long and numerous. Presumably this is related to the need to withstand the abrasive forces during mastication. In addition to a keratinized epithelium and the complex epithelial-connective tissue junction, the lamina propria of masticatory mucosa is often directly attached to the periosteum of the underlying alveolar or palatal bone, i.e. there is no submucosa. This arrangement is also called a "mucoperiosteum". There are exceptions to this generalization, however. In the posterior lateral region of the hard palate, for example, there is a submucosa containing adipose tissue and numerous minor salivary glands.

5. Hard palate Thick, ortho- or parakeratinized epithelium , Thick, ortho- or parakeratinized epithelium , dense connective tissue Mucoperiosteum, except over neurovascular bundles in posterior lateral region; minor salivary glands
SM:submucosa
LP:lamina prperia
EP:epithelium

6. Hard palate
Hard palate

7. Soft palate Thin, nonkeratinized; Taste buds present
Thick with numerous
short papillae
Loose connective tissue;
minor salivary glands

8. Ventral tongue Thin ,non keratinized thin with short
papillae; extensive capillary network
Thin and irregular

9. Floor of the mouth Very thin, nonkeratinized
Short papillae; extensive vascular supply
Loose connective tissue

10. Alveolar mucosa
Thin, nonkeratinized Short papillae Loose connective tissue containing elastic fibers

11. Alveolar mucosa

12. Labial And Buccal mucosa
Very thick, nonkeratinized
Long slender papillae but wide rete ridges,
dense connective fibers Mucosa attached to underlying muscle; minor tissue with elastic salivary glands

13. Labial mucosa
Buccal mucosa

14. Vermilion mucosa
Thin, keratinized Numerous papillae and extensive capillaries Mucosa attached to underlying muscle

15. Lip
vermilion

16. The gingiva
it's a masticatory mucosa, covering the neck of the teeth and continue till the alveolar mucosa. It's divided into 3 parts:
1-free 2-attached 3-interdental
The epithelium is Thick, ortho- or parakeratinized while lamina propria is Long, narrow papillae and rete ridges. Submucosa is dense connective tissue (Mucoperiosteum).

18. Gingival sulcus
it's the invagination made by gingiva and it joins with tooth surface. It extends from gingival margin to the dento-gingival junction. It's depth in healthy gingiva is about 1.8mm, approximate level of free gingival groove. Deeping in gingival sulcus occur in pathological condtion called"pocket".

20. DENTO-GINGIVAL JUNCTION:
It's the junction between the gingiva and tooth surface. It consisted of :
A-sucular epithelium: which is lined the gingival sulcus (non-keratinized) and lack epith. Ridges. It's continuous with gingival epith. And attachment epith.has the same basal lamina.
B-attachment epithelium (junctional epithelium):
This synthesizes the material that attaches it to the surface of the tooth (E.or C.). this extracellular substance with it's morphology and mechanism is called epithelial attachment which is loose so it wear and peelsoff .

22. The Mucogingival and Mucocutaneous Junctions
The boundaries between lining mucosa and masticatory mucosa, as well as between the skin and labial mucosa, are relatively sharply defined.
􀁺 The mucogingival junction is the border between the alveolar mucosa and the gingiva.
The mucocutaneous junction is found at the vermilion zone where the skin is continuous with the labial mucosa. The line separating the skin from the red vermilion zone is sometimes called the vermilion border