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Flashcards in Oral Cavity Deck (310)
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What are the symptoms of xerostomia?

Mucosa: dry, glossy, atrophic changes
Tongue: glossitis, fissured, red, papilla atrophy
Rampant caries
Periodontitis, candidiasis, halitosis
Difficulty in speech and swallowing


What are some treatments for xerostomia?

Inc. water intake
Treat underlying condition
Artificial saliva
Chew gum i.e. trigger receptors


What are the 5 functions of the oral mucosa?

1. Mechanical protection: compression, shearing
2. Barrier: bacteria, toxins, antigens
3. Immunological defence: humoral, cell-mediated
4. Lubricate saliva
5. Innervation: touch, pain, taste


What are the 3 functional classifications of oral mucosa?

1. Masticatory
2. Lining
3. Specialised


Describe the masticatory mucosa

Area: high compression and friction; gingivae, hard palate
Highly keratinised, thick lamina propria


Describe lining oral mucosa

Area: mobile and distensible; cheeks, lips, alveolar mucosa, floor of mouth, ventral tongue, soft palate
Non-keratinised, loose lamina propria


Describe specialised oral mucosa

Area: dorsal surface of tongue (taste buds); vermilion of lips (transition between skin and oral mucosa)


What are the 4 layers of oral mucosa?

Deep to superficial
1. Submucosa
2. CT (lamina propria)
3. BM (basal lamina)
4. Stratified squamous epithelium


Compare keratinised, non-keratinised and parakeretinised stratified squamous epithelium

Keratinised: non-viable cells w/o nuclei, filled with keratins (stratum corneum)
Non-keratinised: viable cells w/ nuclei (no stratum corneum)
Parakeratinised: mix of non-viable cells w/o nuclei, apoptotic cells with shrivelled nuclei


Describe the layers of keratinised stratified squamous epithelial

1. Stratum basale: resting on BM, stem and TA cells
2. Stratum spinosum: large, round, prickly appearance due to desmosomes, produce keratin
3. Stratum granulosum: keratohyaline granules, larger, flatter
4. Stratum corneum: keratinised, mechanical protection, filled with keratins, no desmosomes, sheds off


Describe the layers of non-keratinised stratified squamous epithelium

1. Stratum basale: resting on BM, TA and stem cells, give rise to other layers
2. Stratum spinosum: prickly, larger, rounder, produce keratins
3. Stratum intermedium: larger, flatter, no keratohyaline granules
4. Superficial layer: nuclei present, no desmosomes, sheds off


What are keratins?

Fibrous structural proteins composed of intermediate filaments found in all epithelia


What is the function of the basal lamina?

Mechanical adhesion between epithelium and CT
Barrier between them


What are the 2 layers of the basal lamina?

Lamina lucida: made of laminin, adjacent to epithelia
Lamina densa: made of collagen T4, adjacent to CT


How does the basal lamina link CT to epithelial?



What are the 2 layers of lamina propria?

1. Superficial: thin, loosely arranged collagen
2. Deep: thick parallel bundles of collagen


What cells and structures are present in the lamina propria?

Cells: collagen, elastin, oxytalan fibres, proteoglycans - glycoproteins, macrophages, lymphocytes, mast cells, fibroblast producing ECM

Structures: blood vessels, nerve endings


Describe sulcular epithelium

Not in direct contact with enamel


What is the gingival sulcus?

Natural space between tooth and free gingiva


Describe junctional epithelium

Seals off underlying CT and bone
Direct contact with enamel via hemidesmosomes


Why is the junctional epithelium permeable?

Allows tissue fluid and immune cells to pass through into gingival sulcus for defence against invading OB


Explain how plaque formation damages the mucosa

Plaque causes recruitment of inflammatory cells, initially limited and little neutrophil emigration
As gingivitis continues; heavy neutrophil emigration, gingival crevice enlarged, extensive subgingival plaque
Periodontitis: gingival recession with fibrosis in CT, extension of subgingival plaque, apical migration and ulceration of junctional epithelium, alveolar bone resorption and periodontal ligament loss


What are the 3 main parts of a tooth?

1. Root: below gum line; dentine covered by cementum
2. Crown: visible part; dentine covered by enamel
3. Pulp: centre of tooth, blood and nerve supply


What is the cemento-enamel margin/junction?

Border where enamel and cementum meet


What is the enamel-dentine junction?

Border between enamel and dentine


What are ameloblasts and odontoblasts?

Ameloblasts: enamel secreting cells, move from EDJ to surface
Odontoblasts: dentine secreting cells, move from EDJ to pulp


What are the 3 components of enamel?

1. Hydroxyapatite crystals
2. Organic material: amelogenin, enamelin
3. Little water


What are some of the properties of enamel?

Derived from ectoderm
Can't repair self: some capacity to remineralise
Low tensile strength
Hardest biological tissue
High modulus of elasticity
Semi-permeable membrane: allows ions from salvia in, ionic substitution


What is the function of enamel?

Protective: withstand shearing and impact, resist abrasion


Describe the structure of enamel

Long, hexagonal HA crystallises arranged in rods/prisms grow from EDJ to surface in sinuous path