Gingiva and Oral Mucosa Flashcards
(40 cards)
What are the differences between the oral mucosa and skin
Hair follicles, sweat glands, taste buds, colour differences (dependent on melanin production, degree of keratinisation
What are the differences between keratinised and non keratinised epithelium
Presence of granular cell layer and keratinised layer in keratinised epithelium versus intermediate layer and superficial cell layer in non-keratinised epithelium
Where is keratinised epithelium found?
Attached gingiva/ tongue/ palate
Where is non-keratinised epithelium found?
Buccal mucosa, floor of mouth, vestibule
Name cells that can be found in the epithelium of the oral mucosa
Keratinocytes, melanocytes, langerhan cells, inflammatory cells
What is the function of oral mucosa?
Barrier/ protective function
Sensation, temperature, taste, pain
Secretion of lubrication and buffering
Immunological defence: antimicrobial factors
What are the types of oral mucosa?
Masticatory, lining and specialised
Where can specialised oral mucosa be found?
Dorsal tongue surface, associated with papilla, taste buds
Where can masticatory mucosa be found?
Attached gingiva, hard palate, dorsal tongue surface
High compression and friction, rubbery surface texture, firm, keratinised epithelium
Where can lining mucosa be found?
Soft palate, floor of mouth, ventral tongue surface, Buccal alveolar mucosa
Smooth, moist, soft, pliable
Non-keratinised, thin epithelium, more red- high conc of capillaries underlying
What are the four layers found above the basement membrane in keratinised mucosa
Keratinised layer
Granular layer
Prickle cell layer
Basal cell layer
how is epithelium anchored
Interdigitation between epithelium and lamina propria, rete pegs: epithelial extensions that project into underlying connective tissue
Describe the keratinised layer
Lost all organelles due to autolysis, cells completely filled with keratin
Closely packed tonofilaments surrounded by matrix protein filaggrin= keratin
Keratin is strongly crosslinked by disulphide bonds (mechanical and chemical resistance)
Desmosomes breaking down to allow for desquamation, shedding
20 cells thick
Parakeratinised (nucleated) gum
Orthokeratinised (no nucleus) vermilion border of lip and hard palate
Describe the granular layer
Keratinocytes larger and fatter, lose organelles as they mature
Cytoplasm consists of tonofilaments, tonofibrils and keratohyaline granules
Keratohyaline granules contain proflaggrin, precursor of flaggrin which binds tonofilaments together in stable network
Keratohyaline granules also release lipid rich contents into intercellular space which helps to cement layer and decrease permeability, prevent water loss and form resistant layer
Describe the prickle cell layer
Several cells thick
Round or ovoid cells (keratinocytes)
Keratinocytes form cytokeratin which builds up in the cells forming tonofibrils which form desmosomes (50%) of intercellular space
Describe the basal cell layer
Single cell layer
Demarcates lamina propria from basal lamina
Consists of cuboidal cells (LEAST differentiated) and stem cells
What is the difference between keratinised and non-keratinised mucosa?
Non-keratinised has no granular and keratinised layer, only basal, intermediate and superficial cell layer
Surface layers of non-keratinised mucosa lack keratohyaline granules
Interface between lamina propria and epithelium smoother with fewer and less pronounced rete pegs and connective tissue papillae
Lamina propria of non-keratinised has more elastic fibres, more pliable
What are the cells present in oral mucosa
90% keratinocytes
10% non keratinocytes
Melanocytes: located in basal layer, produces melanin
Langerhans cells: located above basal layer, antigen presenting
Merkel cells: located in basal layer, next to nerve fibres, acts as sensory receptor, found more in masticatory mucosa
What are the functions of lamina propria
Mechanical support for epithelium
Provides nutrition
Sensory function via nerves
Defence via saliva and immunocompetent cells
What are the two layers of lamina propria?
Superficial papillary layer
and Deep reticular layer
What is the difference between papillary layer and reticular layer?
Collagen fibers thin and loosely arranged in papillary layer
Thick, parallel bundles of collagen fibres dominate reticular layer
What is the composition of the lamina propria?
ECM: collagen fibers, mostly type 1
Ground substance: Hydrated gel of glycoproteins and proteoglycans
Macrophages, lymphocytes, mast cells
Nerves, blood cells, salivary glands
Main cell: fibroblast for deposition of type 1 collagen
How are keratin filaments connected to the basal lamina?
the basal lamina forms hemidesmosomes with inserting cytoplasmic filaments along its length
What are the two layers of the basal lamina?
Lamina lucida and lamina densa
