The Oral Mucosa and Gingivae Flashcards
What are the functions of the oral mucosa
- Mechanical protection against both compressive and shearing forces
- Barrier against bacteria, toxins, antigens
- Immunological defences (humoral and cell-mediated
immunity) - Contains minor salivary glands that lubricate the mucosa
- Innervation (sensory nerve endings for touch, pain, taste)
What are the 3 functional classes of the oral mucosa
- Masticatory
- Lining
- Specialised
Where is the masticatory mucosa found, is it keratinised and describe its lamina propria
- in areas of high compression and friction
- gingivae, hard palate
- highly keratinized and thick lamina propria
Where is the lining mucosa found, is it keratinised and describe its lamina propria
• in areas that must be mobile and distensible
• cheeks, lips, alveolar mucosa, floor of mouth, ventral
surface of tongue, soft palate
• non-keratinized and loose lamina propria
Where is the specialised mucosa found
- dorsal surface of the tongue (because of taste buds)
* vermilion of lips (transition between skin-oral mucosa)
What kind of epithelium is in the oral mucosa
Stratified Squamous epithelium
What are the properties/features of the Lamina Propria
Connective tissue
Mainly fibroblasts
ECM rich in collagen
Capillaries and nerve endings
Where is the sub-mucosa and what does it consist of
Under the muscularis mucosa Loose CT Fat deposits Glands Nerves (probably intrinsic) Blood vessels
What are the different categories of stratified squamous epithelium
Keratinised
Non-keratinised
Parakeratinised
What is the surface of keratinised epithelium made of and what is it filled with
Surface made of non-viable cells without nuclei, filled with keratins (stratum corneum)
What is the surface of non-keratinised epithelium made of
Surface consists of all viable cells with nuclei
What is the surface of parakeratinised epithelium made of
Surface made of some non-viable cells without nuclei, and some apoptotic cells with shrivelled nuclei
What are the different layers of the keratinised epithelium
Stratum Corneum - keratinised layer
Stratum Granulosum - granular layer
Stratum Spinosum - prickle cell layer
Stratum Germinativum - stratum basale or basal layer
What does the stratum germinativum (basale) contain a lot of and what is its role
- Contains a lot of progenitor cells
- Gives rise to the epithelial layers above it
What are the cells of the stratum spinosum like and what is its role
- Prickly (spinous), Larger and rounder cells, connected by desmosomes
- Produces keratins that are resistant fibrous cytoskeletal proteins that are composed of intermediate filaments (found in all epithelia)
What are the cells of the stratum granulosum like and what granules can be found
- Cells become larger, flatter and more mature in this layer
- Cytoplasm gradually fills with keratinohyaline granules
What are the cells of the stratum corneum like and what is this layer’s role
- Cells lose all organelles and completely fill with keratins.
- Provides mechanical protection to the mucosa
What allows the stratum corneum cells to shed off for the physiological turnover of epithelial tissue
The desmosomes disappear
What kind of proteins are keratins
Structural
Where are a lot of keratins found
Epithelial cells and hair
What are the layers of non-keratinised epithelium
Superficial cells
Stratum Intermedium
Stratum Spinosum
Stratum Germinativum
What are the cells of the stratum intermedium like and how is it different from the stratum granulosum
- Cells become larger, flatter and more mature
- No keratinohyaline granules
What are the cells of the superficial layer like
Nuclei present in cells
Desmosomes disappear, allowing cells to shed off and physiological turnover
What is the basement membrane found between
It is the interface between the epithelium and connective tissue
What is the role of the basal lamina
Provides mechanical adhesion of epithelium to connective tissue and, at the same time, acts as barrier between them
What synthesises the basal lamina
Synthesized by cells of the stratum germinativum
What are the 2 layers of the basal lamina
- Lamina lucida: adjacent to epithelium (laminin)
- Lamina densa: adjacent to connective tissue (collagen IV)
What is the role of hemidesmosomes in the basement membrane
structures on the cell side of basal lamina that link basement membrane to epithelial cells
What is the lamina propria
Connective tissue underlying the epithelium
Describe the collagen fibres in the superficial and deep layers of the lamina propria
Superficial - thin, loosely arranged collagen fibres
Deep - thick parallel bundles of collagen fibres
What protein is there a lot of in the lamina propria
Collagen
What is the role of the fibroblasts in the lamina propria
Producing the ECM
What defence cells are in the lamina propria
- Macrophages
- Lymphocytes
- Mast cells
Name as many areas of the oral mucosa that have thin epithelia as you can
Floor of Mouth
Alveolar mucosa
Vermilion zone (lips)
Tongue (ventral)
Name as many areas of the oral mucosa that have thick epithelia as you can
Tongue (dorsal) Soft Palate Hard Palate Labial - buccal Gingivae
Name as many parts of the oral mucosa with a keratinised epithelia as you can
Vermilion zone (lips)
Tongue (dorsal)
Hard Palate
Gingivae
Name as many parts of the oral mucosa with a non-keratinised epithelia as you can
Floor of mouth Alveolar mucosa Tongue (ventral) Soft Palate Labial-veccal
What is leukoplakia and what are some risk factors
- White lesion of the oral mucosa
- Increased thickness of keratinised layer
- Associated with smoking and infection
- Can exhibit malignant transformation
In the gingiva point out the “knife edge” papillae, gingival crevice, free gingiva, attached gingiva and mucogingival junction
knife edge papillae = thinnest part between teeth
What is the gingival sulcus
Small crevice between gums and enamel of tooth
What is the difference between gingival, sulcular and junctional epithelium
Gingival - epithelium of normal gums
Sulcular - epithelium in the sulcus, not touching enamel
Junctional - epithelium touching the enamel
What does the CT under the gingival epithelium connect the epithelium to
Alveolar bone
Is the sulcular epithelium keratinised and how deep is the gingival sulcus when healthy
Non-keratinised
0.5-2mm. deep in health
Is the junctional epithelium keratinised and what connects it to the enamel
Non keratinised
Hemidesmosomes
What does the permeability of the junctional epithelium allow for
Tissue fluid and immune cells to pass through into the gingival sulcus for defence against invading oral bacteria
What are some symptoms of chronic gingivitis, gotta get all sciencey to get this right
- Heavy neutrophil emigration into the enlarge gingival crevice
- entensive gingival plaque
- no loss of CT attachment
- Plasma cell dominated inflammatory infiltrate
What are some symptoms of chronic periodontitis
- Gingival recession with fibrosis in CT
- Continued extension of sub gingival plaque
- Extension of inflammatory infiltrate
- Apical migration and ulceration of the junctional epithelium
- Alveolar bone resorption and periodontal ligament loss
