Oral Mucosa Flashcards
What is the oral mucosa?
A moist lining which almost continuously lines the oral cavity
What are the main components of an oral mucosa?
- Epithelium - SSK/SSNK
- Lamina propria - Collagen type I and III
- Submucosa - Loose CT found in cheeks, lips and parts of hard palate
What are 5 functions of the oral mucosa?
- Protection against compressive and shearing forces
- Barrier to microorganisms#
- Immunological defence
- Sensitivity
- Reflexes e.g. swallowing and retching
What are the two areas of the oral mucosa?
- Outer vestibule - Bound by lips and cheeks
2. Oral cavity proper - Bound by alveolar bone and gingiva, hard and soft palates and floor of the mouth and tongue
Name 3 types of mucosa found in the oral cavity
- Lining
- Masticatory
- Specialised
What 5 places is lining mucosa found?
- Cheeks
- Lips
- Ventral surface of tongue
- Floor of mouth
- Soft palate
What 2 places is masticatory mucosa found?
- Gingiva
2. Hard palate
Where is specialised mucosa found?
Dorsum of tongue
What lines lining mucosa?
Stratified squamous non-keratinising epithelium
Why does lining mucosa need a submucosa and lamina propria?
It is found in regions where a moveable base is needed i.e. during speech or mastication
What are 2 points of clinical relevance with regards to lining epithelium?
- An incision will tend to need sutures due to tissue movement
- Injections are less painful
What lines masticatory mucosa?
Stratified squamous keratinising epithelium
What gives masticatory mucosa a firm base?
Highly interdigitated epithelium and lamina propria
What are 2 points of clinical relevance with regards to masticatory epithelium?
- Sutures are rarely needed as little tissue movement
2. Injections are more painful
From the deepest layer to the most superficial layer, what are the 4 layers of the epithelium of oral mucosa?
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum corneum
What is the main cell of mucosal epithelium?
Keratinocyte
Name 3 other cells which can be found in mucosal epithelium
- Melanocytes
- Langerhans cells
- Merkel cells
How does oral melanoma arise?
Mutated melanocytes in the basal layer of the mucosal epithelium
What projections cover the dorsal surface of the tongue?
Lingual papillae
What are 4 types of lingual papillae which can cover the tongue?
- Filiform - Narrow and conical
- Fungiform - Mushroom-shaped
- Circumvallate - Wall-like
- Foliate - Leaf-shaped
What is the function of filiform papillae?
Provide grip between tongue and food
What epithelium lines filiform papillae?
Thick layer of keratinised epithelium
What is the function of fungiform papillae?
Contain taste buds
What epithelium lines fungiform papillae?
Thin layer of keratinised epithelium
What are circumvallate papillae?
Raised, rounded structures located anterior to sulcus terminalis, surrounds by a trench containing taste buds
What are filiform papillae found on the tongue?
Cover entire surface of tongue
What are 3 junctions found in the oral mucosa?
- Mucocutaneous - Skin and lips
- Mucogingival - Gingiva and alveolar muscle
- Dentogingival - Tooth and gingiva
How does the epithelial thickness change at the mucocutaneous junction?
Thickness increases from external skin to internal mucosa
What is found between the internal mucosa and external skin at the mucocutaneous junction?
Vermillion zone - Thin, keratinised epithelium with capillary loops in CT coming close to the surface
What is the mucogingival junction?
Transition between thin, loose, moveable alveolar mucosa and thick, firm, tightly attached gingiva
What are 2 major differences between gingiva and alveolar mucosa?
- Gingiva is keratinised
2. Gingiva is a paler pink colour
What is the dentogingival junction?
The junction between the gingival tissue and tooth surface
What are the 3 parts of the epithelium which make up the dentogingival junction?
- Free gingiva
- Sulcular epithelium
- Junctional epithelium
What binds junctional epithelium to enamel of the tooth?
Basal lamina and hemidesmosomes
What part of the tooth germ is the dentogingival junction derived from?
Enamel organ
What is a potential issue with the gingival sulcus?
Plaque formation can occur within the sulcus
Give a brief description of parotid glands
Branched acinar gland with exclusively serous cells
Give a brief description of submandibular glands
Branched tubulo-acinar gland with both serous and mucous cells
What is the function of serous demilunes in the submandibular gland?
Secrete lysosomes which hydrolyse bacterial walls
Give a brief description of sublingual glands
Branched tubulo-acinar gland with mucous cells and serous cells occurring exclusively as demilunes
