Oral Mucous Membrane PDF

Oral mucous membrane Dr Sandeep Gupta Oral Pathologist Oral Mucous Membrane Hard palate Dorsal surface of the tongue...

Oral mucous membrane Dr Sandeep Gupta Oral Pathologist Oral Mucous Membrane Hard palate Dorsal surface of the tongue Check mucosa Floor of mouth Gingiva Ventral surface Vestibular of the tongue Alveolar mucosa fornix Labial mucosa Functions of the oral mucosa Protection  Sensation  Secretion  Thermal regulation?  Functions of oral mucous membrane: 1. Protection: the major function is to protect deeper tissues and structures from mechanical, thermal and chemical agents, also act as biological barrier against bacteria and their toxins 2. Sensation: there are many sensation can be sensed in mouth like temperature, touch , pain taste sensation and some reflex by certain receptors ( swallowing, salivation, water satisfaction and gagging reflex) 3. Secretion: production of saliva. 4. Thermal regulation: as by panting in animals by evaporation of water to control temperature.  Histological structure Oral Mucosa Consists of 2 major components:- Oral Epithelium Lamina Propria  LAMINA PROPRIA Is the connective tissue layer immediately below the epithelium. Can be divided into the papillary layer & reticular layer. In the papillary layer, finger-like projections of connective tissue extend into the deep surface of the epithelium. An increase in the number & length of the papillae is seen in areas where mechanical adhesion between the epithelium & lamina propria is required (masticatory mucosa). 7  In areas of lining mucosa, the reticular or subpapillary layer predominates. The blood supply consists of a deep plexus of large vessels in the submucosa, which gives rise to a secondary plexus in the papillary layer of the lamina propria. Capillary loops extend into the connective tissue papillae. The epithelium is avascular; therefore, its metabolic needs must come via the vessels of the lamina propria. 8 THE LAMINA PROPRIA CONSISTS OF THE PAPILLARY LAYER & RETICULAR LAYER, BELOW WHICH IS SUBMUCOSA. 9  Histological Structure Lamina propria Lamina Propria may be:- Directly attached to periosteum of alveolar bone or Overlay the Submucosa  Submucosa is formed of C.T; the nature of this C.T. determines whether mucous membrane is loosely or firmly attached to underlying structure.  Submucosa contains glands, B.Vs, nerves & adipose tissue.  SUBMUCOSA In most areas of the mouth, the submucosa is absent or limited. Serves primarily as an attachment for the lamina propria to the underlying bone or skeletal muscle. Found in the cheeks, lips, & parts of palate, & is a less dense component than the lamina propria. Its functions are nutrition & defense. 11  It is the site containing adipose tissue & minor salivary glands in the oral cavity. In the bony areas with no submucosa, fibers of the lamina propria attach tightly to bone. The mucosa & lamina propria in these areas is generally referred to as mucoperiosteum. 12  Oral Mucous Membrane Classification 1-Keratenized mucosa ( Masticatory mucosa) (A) Gingiva (B) Hard palate 2- Non-keratenized mucosa (Lining mucosa) (A) Firmly attached (B) Loosely attached I- Soft I- Floor of IV-ventral II-Vestibule palate II-lip III-cheek mouth S tongue III-alveolar 3- Specialized mucosa mucosa Dorsal surface of tongue Types of Mucosa Keratinized St. Sq. Epith. Basal cell laye (stratum basale) Prickle ’spinous’ cell layer (stratum spinosum) Granular cell layer (stratum granulosum) Cornified cell layer (stratum corneum)  Keratinized Epithelium Cells are arranged in 4 layers:- Basal (stratum basal), Spinous (stratum spinosum), Granular (stratum granulosum) & Cornified (stratum cornium).  Basal cell layer Cells are cuboidal or columnar & are arranged in a row on a B.M. Cells are attached to each other by a cellular junction & also to B.M  Spinous cell layer Several rows of polyhedral cells of different shape & size & larger than basal cells. Basal cells & spinous cells constitute more than 1/2 thickness of epithelium. Cells of spinous layer are joined together by intercellular bridges giving the cells a prickly appearance  Granular cell layer Lies above prickle cell layer & is made up of several rows of flattened epithelial cells. The cells contain large no. of small granules called keratohyaline granules.  Cornified layer In K.E is the final stage in maturation. Cells are termed epithelial squames; these are cells that shed, necessitating the constant turnover of epithelial cells Nonkeratinized St. Sq. Epith. basal intermediate superficial  Keratinized & non-Keratinized mucosa Stratum cornium Stratum superficial Stratum granulosum Keratohyaline Gs. Stratum Stratum spinosum intermedium Stratum basal Keratenized epithelium Non-keratenized epithelium  Keratinocytes & Non-keratinocytes  Keratinocytes Constitute the major part of epithelial cells The cells are arranged in different layers During maturation they either change to keratin or share in keratin formation These cells have the following criteria:-  Always present in sheets & attached to each other by one or more type of cellular junctions  Cytoplasm of these cells is stained with H & E  Cytoplasm contains the tonofilaments  Non-keratinocytes Present in both keratinized & non-keratinized epithelium & have the following criteria:- 1- Appear as clear cells by ordinary H&E stain, they need special stains 2- Present as scattered cells & not in sheets 3- A clear hallows around their nuclei 4- Their cytoplasm is free from tonofilaments 5- No cellular junctions 6- Do not play any role in synthesis of keratohyaline granules or keratin  1- Pigment cell 2- Langerhan’s cell 3- Merkel’s cell (Melanocyte, blast) Shape Small body with long slender & branched Do not process Similar in shape have long Contain melanin Contain granules processes granules (Langerhan’s granules) Contain small (melanosomes) membrane bounded granules Location Basal & parabasal High level cell and Basally in layers may be found at lower epithelium levels. H&E Not stained so- Not stained so-called Not stained so- Stain called (Clear dentritic cell) called (Clear dentritic cell) (Clear but not dentritic cell) Special DOPA reaction (for Gold chloride stain tyrosinase enzyme) Origin Neural crest cells Bone marrow Neural crest cells Cell No No tonofilaments Little tonofilaments junction tonofilaments No desmosomes Little desmosomes No Nerve cell seen to be desmosomes associated with the cell with synapse-like cleft Function Pigmentation Neural element. Responding to touch If melanosomes Degenerated engulfed by melanocyte epithelial cell Intra epithelial called Macrophage (Melanophore) or Regulatory cells by C.T. cell (control epith. Cell (Melanophage) division & differentiation) Uptake & processing of antigen in contact allergic reaction 4- Inflammatory cells They are transiant cells Melanin pigmentation of basal keratinocytes JUNCTION OF EPITHELIUM & CONNECTIVE TISSUE Connective tissue, with its inductive properties, exerts control over the overlying epithelium. The basement membrane is composed of three parts:- - Lamina lucida, which is less dense & is toward the epithelial side; - Lamina densa, middle of the three parts; - Lamina reticularis, which is less dense than the lamina densa & is located next to the lamina propria. 30  Type IV collagen & laminin, a glycoprotein, are major components of the lamina densa. Basal cells of the epithelium are not attached to the connective tissue proper, but rather form mechanical adhesions with the basal lamina. These attachments are hemidesmosomes. Fine collagen fibers attach to lamina on the connective tissue side. These fibers are anchoring fibers, composed of type VII collagen. 31 32  Keratinized Mucosa Masticatory Mucosa During mastication, parts of oral mucosa are subjected to forces & pressure Gingiva  Hard Palate  Macro-Anatomy of Gingiva Free gingival groove Free gingiva Interdental papilla Attached gingiva Mucogingival junction Alveolar mucosa Pigmentation Attached gingiva Interdental Papilla & Gingival Col Gingival col( non- keratenized) Histology of Gingiva Stratified squamous keratenized epithelium Tall Epithelial rete peg Numerous C.T papilla Slender Lamina propria Irregular No submucosa Gingival fibers Circular group Dento-gingival group Alveolo-gingival group Dento-periosteal group  Macro-Anatomy of palate Incisive papilla Palatine gingiva Rugae area Antero-lateral area (fatty zone) Postero- lateral area Median (glandular palatine zone) raphe Soft palate Uvula  Histology of Hard Palate Epithelial rete pegs are tall & numerous Mucosa Fatty zone Glandular zone Submucosa Non-Keratinized Mucosa Lining Mucosa Present in areas not subjected to high levels of friction but is mobile & distensible Firmly attached to underlying muscles  Soft Palate  Lip  Cheek  Ventral Surface of tongue Loosely attached to underlying structures as bone, fascia or muscle  Floor of mouth  Vestibule  Alveolar Mucosa  Soft palate Nasal side Oral side Respiratory epithelium Lip Mucous side Lip Vermilion border Skin side Skin Skin appendages Hair follicle Sebaceous gland Sweat glands Nonkeratenized Cheek mucosa epithelium Mixed salivary gland Specialized Mucosa Dorsal Surface of Tongue  Specialized Mucosa Tongue Dorsal Surface  Tongue papillae 1- Filliform pap. 2- Fungiform pap. Taste bud 4- Folliate pap. 3- Circumvallate pap. Filiform papillae Fungiform papillae  Circumvallate papillae “SEM” von Ebner salivary glnds  CircumVallate papilla Trough  Circumvallate papillae trough Von Ebner salivary gland Foliate papillae Taste Bud SEM H & E stain Taste Bud Taste distribution  Taste sensation Bitter Sour Salt Sweet Posterior Third of Tongue lymphatic part Lingual tonsil Weber salivary gland (Pure mucous gland Lymphatic nodules Lingual crypt (follicles) Weber salivary glands  Loosely Attached “Movable”mucosa Alveolar mucosa loosely attached to periosteum Vestibular fornix allows mobility of lips and cheeks Floor of the mouth loosly attached to underlying structures allows mobility of the tongue  Loosely Attached“Movable”mucosa Alveolar mucosa mucogingival junction Epithelium: st. sq. nonker. epith., few or no epith. ridges lamina Loose C.T, propria: collagen & elastic fibers Submucosa: thick elastic fibers & mixed salivary glands Floor of the mouth Very tin epith. lamina propria highly vascularizes Vestibular fornix  ventral surface of the tongue Firmly attached to underlying muscles Thin non.kert. st.sq. epith. Sew-teeth appearance of epith ridges Thank You