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Flashcards in Oral Cavity Deck (310)
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31

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

32

What are some treatments for xerostomia?

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

33

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

34

What are the 3 functional classifications of oral mucosa?

1. Masticatory
2. Lining
3. Specialised

35

Describe the masticatory mucosa

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

36

Describe lining oral mucosa

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

37

Describe specialised oral mucosa

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

38

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

39

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

40

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

41

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

42

What are keratins?

Fibrous structural proteins composed of intermediate filaments found in all epithelia

43

What is the function of the basal lamina?

Mechanical adhesion between epithelium and CT
Barrier between them

44

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

45

How does the basal lamina link CT to epithelial?

Hemidesmosomes

46

What are the 2 layers of lamina propria?

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

47

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

48

Describe sulcular epithelium

Non-keratinised
Not in direct contact with enamel

49

What is the gingival sulcus?

Natural space between tooth and free gingiva

50

Describe junctional epithelium

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

51

Why is the junctional epithelium permeable?

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

52

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

53

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

54

What is the cemento-enamel margin/junction?

Border where enamel and cementum meet

55

What is the enamel-dentine junction?

Border between enamel and dentine

56

What are ameloblasts and odontoblasts?

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

57

What are the 3 components of enamel?

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

58

What are some of the properties of enamel?

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

59

What is the function of enamel?

Protective: withstand shearing and impact, resist abrasion

60

Describe the structure of enamel

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