Oral Mucosa

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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

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