Oral mucous membrane

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.

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

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.

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

Hard palate Hard palate

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

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

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

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

Alveolar mucosa

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

Labial mucosa Buccal mucosa

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

Lip vermilion

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).

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".

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 .  

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