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Oral Mucosa

STUDY
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Oral Mucosa
-Continuously lines the oral cavity.
-Composed of Stratified Squamous Epithelium
-Overlying Lamina Propria
-Perforated by ducts of saliva glands
-Regional differences
Basement Membrane
Lies between the epithelial & connective tissues of the oral mucosa.
3 main types of Oral Mucosa
Lining mucosa, Masticatory mucosa, & Specialized mucosa
Lining Mucosa
includes the buccal mucosa, labial mucosa, alveolar mucosa, & the mucosa lining the floor of the mouth, ventral surface of the tongue, & soft palate.
Lining Mucosa
Histologically it is associated with nonkeratinized stratified squamous epithelium.
Masticatory mucosa
includes the attached gingiva, the hard palate, & the dorsal surface of the tongue.
Masticatory mucosa
Histologically it is associated with keratinized squamous epithelium.
Oral Mucous Membrane
Epithelial portion: SSE flat in shape.
Oral Mucous Membrane
-Several layers deep
-Protected areas
-Non-keratinized with nuclei healthy & normal
-Hard palate and gingiva
Protected areas of Oral Mucous Membrane
Surface epithelial sloughed off into saliva as new cells produced by basal layer.
Hard palate and gingiva of Oral Mucous Membrane
-Keratinized
-Cells lose nuclei & cell boundaries
-For noncellular, tough, protective later (keratin layer)
Connective tissue portion of Oral Mucous Membrane
-Fibrous CT
-Blood vessels & nerves seperated from SSE by then basement membrane
-Underneath the Oral Mucous Membrane
-Allows for increased surface area
Stratified Squamous Epithelium
Epithelium boundary between the connective tissue & epithelium.
Lamina Propria
finger-like projections of oral mucosa
"Non-keratinized epidermis" layers of Lining Mucosa
-Stratum Superficiale
-Stratum Intermedium/Spinosum
-Stratum Basale
"Dermis/Lamina propria" layers of Lining Mucosa
-Papillary Layer
-Reticular Layer
Basal Lamina/Basement Membrane
seperates the Non-keratinized epidermis layers & the Dermis/Lamina Propria layers of the Lining Mucosa
Stratum Superficiale
Top layer, flattened squamous, dispersed, small nuclei's present, cells die & sluffed off.
Stratum Intermedium/Spinosum
-Larger, oval typed cells, dispersed tunnel fibers
-Largest bulk of the 3 layers
Stratum Basale
Germinative layer, single layer
Hemidesmosomes
[snaps]
-Cellular part connected to noncellular.
Desmisomes
Cellular connected to cellular.
Rete Peg's
Epithelial ridges
Set up of Lining Mucosa
-Stratum Superficiale
-Stratum Intermedium/Spinosum
-Stratum Basale
Basal Lamina/Basement membrane
-Dermis/Lamina Propria
-Submucosa
Masticatory Mucosa
On attached gingiva, hard palate, marginal gingiva
"Keratinized Epidermis" layers of Masticatory Mucosa
-Stratum Corneum
-Stratum Granulosum
-Stratum Intermedium/Spinosum
-Stratum Basale
"Dermis/Lamina Propria" layers of Masticatory Mucosa
-Papillary Layer
-Reticular Layer
Stratum Corneum
-"keratin layer", thin, flattened, dehydrated cells, no nuclei, soft keratin feeling, fingernail feeling, nonliving material, impervious to bacteria (prevents bacteria from getting into between layers.)
Stratum Granulosum
a lot of granulum cells that contain keratohyline, 3-5 cells thick, stain dark, granulum layer.
Stratum Intermedium/Spinosum
larger, oval cells, slightly flattened, lost ability to undergo mitosis.
Stratum Basale
single layer, cuboidal deepest, superior to basil lamina.
Prickle Cell layer
appears on Stratum Intermedium/Spinosum layer of Masticatory mucosa.
Masticatory mucosa
-Keratinized (thick) epithelial tissues, firmer, more use to attrition.
Set up of Masticatory Mucosa
-Stratum Corneum
-Stratum Granulosum
-Stratum Intermedium/Spinosum
-Stratum Basale
Basal Lamina/Basement Membrane
-Dermis/Lamina Propria
-Submucosa
Fordyce's Spots
Granules, normal variant, visible as small, yellowish elevations on the surface of the mucosa.
Specialized Mucosa
-found on the dorsal & lateral surface of the tongue.
-composed of epithelium & lamina propria
-not on lingual surface
3 types of Stratified Squamous Epithelium
-Nonkeratinized
-Orthokeratinized
-Parakeratinized
Nonkeratinized
have similar epithelial histological traits with some regional differences.
Nonkeratinized
-Lining mucosa
-No large rete pegs or connective tissue- finger-like projections
Keratinocytes
often used by researchers for the epithelial cells in oral mucosa because they can produce keratin either naturally or when the tissue is traumatized.
Parakeratinized
-immature form of orthokeratinized
-same layers, more indistinct.
-not as many finger-like projections as ortho.
Oral Mucosa
Acts as barrier to bacterial invasion, mechanical irritation, & protects against dryness.
Small number of cells located in epithelium
Melanocytes, White Blood Cells, Langerhan's Cells, Granstein Cells,, & Merkel Cells
Squames
Flattened platelike epithelial cells
Prickle Layer
A prickly or spiky look results when the individual dehydrated epithelial cells are still joined at their outer layers.
Keratohyaline Granules
Form a chemical precursor for the keratin found in the more superficial layers.
Keratin
A soft, opaque, waterproof material formed from a complex of keratohyaline granules & intermediate filaments from the cells.
The main difference between orthokeratinized & parakeratinized is..
in the cells of the keratin layer.
In Parakeratinized..
The most superficial layer is still being used or lost, these cells of the keratin layer contain not only keratin but also nuclei, unlike orthokeratinized.
Nonkeratinized SSE
-Located in the superficial layers of lining mucosa.
-The lining mucosal tissues have similar epithelial histological traits even though they have some regional differences.
-Most common form of epithelium in the oral cavity
Orthokeratinized SSE
-Associated with the hard palate & attached gingiva.
-Also associated with the specialized mucosa of the lingual papillae on the dorsal surface of the tongue.
-Least common form of epithelium
Parakeratinized SSE
-Associated with attached gingiva & the tongue's dorsal surface.
-Also associated with the specialized mucosa of the lingual papillae on the dorsal surface of the tongue.
-Immature form of Orthokeratinized
-Same layers as Ortho.
-Cells of the keratin layer contain keratin & nuclei
Hyperkeratinized Tissue
-Nonkeratinized epithelium may transform into a keratinizing form in response to frictional or chemical trauma.
-Can result if enough trauma from biting cheek occurs or from people who smoke.
Fibroblast
-The most common cell in the lamina propria.
-Makes collagen
Other cells present in the lamina propria..
White blood cells, such as PMNS, mast cells, macrophages, & lymphocytes
Lamina Propria
-Made up of connective tissue
-Main fiber: Collagen
-Elastic Fibers
Layers of Lamina Propria
-Papillary layer
-Dense layer (Reticular layer)
Papillary Layer of Lamina Propria
-Puts finger-like projections into epithelial.
-Consists of loose connective tissue, blood vessels, & nerve tissue.
Taste Buds
-Barrel-shaped organs of taste from epithelium
-30-80 spindle shaped cells
-Renewal rate: approximately 10 days
-4 taste sensations
Cells of Taste Buds
-Supporting Cells
-Taste Cells
Regions located in the Oral Cavity
Lining mucosa, labial mucosa, buccal mucosa, alveolar mucosa, floor of the mouth, ventral surface, soft palate & the masticatory mucosa, attached gingiva, & hard palate
Stippling
Clinically little depressions which give the surface of the attached gingiva an orange-peel appearance.
Mucogingival Junction
Located between the pinker attached gingiva & the redder alveolar mucosa.
Mucoperiosteum
Loose connective tissue acting as a periosteum to the underlying bone.
Graft Procedure
Performed to reduce the amount of gingival recession on the root, which is when keratinization is taken into consideration.
Lingual Papillae
-Discrete structures or appendages of keratinized epithelium & lamina propria.
-Found on the dorsal tongue surface
4 types of Lingual Papillae
Filiform, Fungiform, Foliate, & Circumvallate
The 3 types of Lingual Papillae associated with taste buds
Fungiform, Foliate, & Circumvallate
Filiform
Clinical Appearance:
-Pointed Structure
Histological Features:
-Thick layer ortho/para epithelium
-Overlying core of Lingual Papillae
-No taste buds present
Fungiform
Clinical Appearance:
-Mushroom shaped
Histological Features:
-Thin layer of ortho/para epithelium
-Overlying vascularized core of Lingual Papillae
-Taste buds present
Foliate
Clinical Appearance:
-Vertical ridges
-Leaf shaped
Histological Features:
-Layer of ortho/para epithelium
-Core of Lingual Papillae
-Taste buds in Epithelium layer
-Function-taste
Circumvallate
Clinical Appearance:
-Mushroom shaped
Histological Features:
-Ortho/para epithelium
-Overlying core of Lingual Papillae
-Many taste buds surround
-Von Ebner's salivary glands- serous
How does the process of taste take place?
Dissolved molecules of food contact the taste receptors at the taste pore. Sensory neuron processes receive messages of taste sensation by way of receptors. The nerve is then sent to the CNS where it is identified as a certain type of taste.
von Ebner's Salivary Glands
Have ducts that open into the trough, flushing the area near the taste pores to introduce new taste sensations from several sequential food molecules. They are located in the submucosa deep to the lamina propria of the circumvallate lingual papillae.
Melanin
Occupy a position in the basal layer of the Stratified Squamous Epithelium between the dividing epithelial cells.
Turnover time for the Oral Mucosa
is higher than for the skin.
Gingival Epithelium
Attaches to the tooth, has the highest turnover time, 4-6 days of all the oral tissues.
Hard Palate
has the lowest turnover time, 24 days.
Granulation Tissue
-the immature connective tissue formed during initial repair.
-replaced by scar tissue
-white-ish, not as pink
The oral mucosa shows ____ scar tissue than skin..
Less. Either clinically or histologically after repair than does the skin because fewer fibers are located in this area than in the skin when it undergoes a similar injury.
Renewal rate of Oral Mucosa
Higher than for skin.
Aging of Oral Mucosa
-Similar to other mucosal tissues of body
-Taste buds reduced
-Thickness & number of rete ridges diminish
Aging of Oral Cavity
-Reduction of stippling
-Increase in Fordyce's granules
-Enlargement in lingual veins
Renewal Rate for Hard Palate
24 days
Renewal Rate for the Floor of the Mouth
20 days
Renewal Rate for Buccal & Labial Mucosa
14 days
Renewal Rate for Attached Gingiva
10 days
Renewal Rate for Taste Buds
10 days
Renewal Rate for Junctional Epithelium (attached to tooth)
4-6 days