Introduction to oral mucosa Flashcards
List the cells found in the squamous epithelium of the oral mucosa
- Keratinocytes
- Melanocytes
- Langerhans cells
- Neurosensory cells
- Lymphocytes
What cell is predominant in the squamous epithelium
Keratinocytes
List the layers of the squamous epithelium
- Basal cell layer
- Prickle cell layer
- (sometimes) keratinised layer
What does the basal cell layer of the squamous epithelium rest on?
The basement membrane
How are keratinocytes attached?
Via desmosomes
How are keratinocytes attached to the basement membrane
Hemidesmosomes
What is the importance of the basement membrane?
Maintains integrity of the mucosa by ‘sticking’ the squamous epithelium to the lamina propria
What are the two types of keratinisation seen in oral mucosa?
Parakeratinisation
Orthokeratinisation
Describe the cells in parakeratinisation
Surface keratinocytes are flattened and the nucleus is dark and shrunken (pyknotic)
They are eventually lose by desquamation
Describe the cells in orthokeratinisation
Granular cell layer present between the prickle and keratinised layer, containing keratohyaline granules
The surface squares are flat with no visible nucleus
Role of melanocytes
Synthesis of melanosomes
Role of Langerhans cells
Antigen trapping and processing
What are the neurosensory cells in the squamous epihtelium
Merkel cells
Taste budes
Role of merkel cells
Tactile sensory cells
What is the lamina propria
Connective tissue directly under the squamous epithelium
What are the layers of the lamina propria
Corium (superficial layer) Reticular layer (deeper layer)
Describe the composition of the lamina propria
Fibrous tissue with a rich neuromuscular supply
Fibroblasts which form collagen, elastin and extracellular matrix proteins
List the other cells found in the lamina propria
Langerhans, macrophages, mast cells and lymphocytes
What is found beneath the oral mucosa?
Either
- Submucosa (in oral mucosa)
- LP continuous with periosteum (in oral mucoperosteum)
What is the submucosa composed of?
- Fibrous tissue, adipose tissue, minor salv glands and neuromuscular bundles
Where is the oral mucoperiosteum found?
Covering the maxilla and mandible
Describe the difference between oral mucosa and oral mucoperiosteum
Oral mucosa has a submucosa
Oral mucoperiosteum has no submucosa, instead the LP is continuous with the periosteum that overlies the bone
What factors influence the appearance of mucosa?
- Thickness
- Amount of keratinisation
- Melanin or other pigments
- Vacularity of the LP
List the three main regional mucosal patterns and their relative %
Lining - 60%
Masticatory - 25%
Specialised - 15%
List the areas with lining mucosa
- Vermillion border
- LM, BM, FOM and ventral tongue
- Soft palate
- Alveolar mucosa
List the areas with masticatory mucosa
Hard palate
Gingiva
What is the reason for masticatory mucosa?
- Thick epithelium to enable resistance to heavy loading
- Production of an inelastic seal (attached mucosa)
List the area with specialised mucosa
Dorsum of the tongue
Why is specialised mucosa, ‘special’?
- Essentially masticatory mucosa but it is special due to the sensory component (taste buds)
What is the dorsum of the tongue organised into?
Lingual papilla
Describe keratinisation of the gingiva by location
- Attached gingiva and external aspect of free gingiva = para and ortho
- Sucular epithelium - non-keratinised
List the junctions in the oral mucosa
Mucocutaneous
Mucogingival
Dentogingival
Where is the mucocutaneous junction found?
Beterrn skin and oral mucosa of the lips
Where is the mucogingival junction found?
Between attached gingiva and alveolar mucosa
How can you clinically identify the mucogingival junction?
Scalloped border with slight indentation and contrasting change in colour
What is the dentogingival junction
Where the oral mucosa meets the tooth
What is the junctional epithelium?
The floor of the sulcus and the epithelium cervical to it
It is attached to the tooth
What does the junctional epithelium arise from?
Reduced enamel epithelium of the tooth germ
Describe the junctional epithelium
Stratified squamous, non-keratinised epithelium
What is the sucular epithelium?
Epithelium lining the walls of the sulcus and is continuous with the rest of the oral mucosa
What are the types of lingual papilla
Filliform
Fungiform
Circumvallate
Foliate
Which papilla is most common?
Filliform
Gives the tongue the velvet appearance
Describe fungiform papilla
Dome shaped
Non-ker and keratinised
Describe the location of circumvallate pappila
V shaped line anterior to the sulcus terminals of the junction between middle and posterior third of the tongue
Describe the location of foliate papilla
Postero-lateral tongue
WHAT IS FOLIATE PAPILLA ASSOCIATED WITH
the lingual tonsil
Which papilla does not contain taste buds
Filliform (the most common type)
List the normal variable features of oral mucosa
Leukodema
Fordyce spots
Sublingual varicose
Lingual tonsil
Describe leukodema
Translucent or milky white with a folded appearance to the mucosa
Common in those with racial pigmentation
Describe Fordyce spots
Sebaceous glands in the oral mucosa
They are small, yellow bodies located on the upper lip, cheeks and anterior pillar of the fauces
What are sublingual varicies
Varicosities of the branches of the sublingual veins
Usually incr with age and associated with smoking or CVD
What is the lingual tonsil made of? where is it located?
- Mucosa-associated lymphoid tissue (MALT)
- Postero-lateral tongue
What pathologies are associated with lingual tonsil?
- Trauma from teeth/dentures
- Reactive limped hyperplasia secondary to local inflammation or infection
- Obstruction and cystic dilation of tonsillar crypts
What is Waldeyer’s ring
Largest accumulation of lymphoid tissue found in the posterior aspect of the oral cavity
What makes up waldeyer’s ring
Lingual, palatine and pharyngeal tonsils
What is linea alba
White line on the buccal mucosa, at the level of the occlusal plane
Keratinisation in response to trauma (cheek biting)
Histology of the lining mucosa
Non-keratinised stratified squamous
Except for the vermillion border that is orthokeratinised
What are the features of the lining mucosa
Stretched and compressed
The presence of the submucosa allows compression of the superficial tissue
Histology of masticatory mucosa
Keratinised stratified squamous
Type of keratinisation of the hard palate
Orthokeratinised
Histology of specialised mucosa
Thick, keratinised and non-keratinised
The papilla are discrete structures of keratinised epithelium and LP
