Oral Mucous Membranes Flashcards
What are the main functions of mucous membranes?
-absorption
-excretion
-protection
Where is masticatory mucosa located?
gingiva and hard palate
Where is lining mucosa located?
-alveolar mucosa
-buccal mucosa
-floor of the mouth
-ventral surface of the tongue
-soft palate
Where is specialized mucosa located?
on the dorsal surface of the tongue
Which type of oral mucosa is keratinized?
masticatory
Where are taste buds located?
in specialized mucosa
What is mucoperiosteum?
a periosteum with a mucosal surface (close proximity of mucous membrane) with the periosteum of bone to form an apparent thin layer
What are the two microscopic organizations of oral mucous membranes?
1: epithelium
lamina propria
submucosa
periosteum
2: epithelium
lamina propria
periosteum
What are the layers of cells in the epithelial cell layer?
-stratum corneum (keratin layer)
-stratum granulosum (granular cell layer)
-stratum spinosim (spinous cell layer)
-stratum basale (basal cell layer)
What are some characteristics of stratum corneum?
-no nucleus
-high levels of keratin
What are the epithelial rete pegs?
projections of epithelial tissue that insert into the connective tissue to lock the epithelium into place
What are connective tissue papillae?
projections of connective tissue that interlock with the epithelial rete pegs
What are characteristics of the epithelium of oral membrane mucosa?
-rests on basement membrane
-exhibit one of more specialized intercellular attachments
-avascular
-exhibit a high degree of cellularity and relatively low volume of extracellular matrix
-may exhibit cellular polarity
What does cellular polarity do?
-allows cells to exhibit apical, basal, and lateral borders
-expressed in the distribution of cytoplasmic organelles
What is orthokeratosis?
refers to normal keratin formation with clinically normal presentation
What is parakeratosis?
retention ofpyknotic nuclei in the stratum corneum
What is hyperkeratosis?
abnormal thickening of stratum corneum
-may exhibit aberrant patterns of keratinization
What is dyskeratosis?
abnormal keratinization below the level of the stratum corneum
-keratinization within the stratum granulosum and/or stratum spinosum
What is acanthosis?
refers to hyperplasia of the epithelial layers
(increase in number of cells)
What is acantholysis?
loss of intercellular attachments between epithelial cells
-loss of desmosomes
What is metaplasia?
reversible change in which one adult cell type of replaced by another
-transitions of columnar to squamous epithelium in the respiratory tract due to smoking
What is dysplasia?
disorderly by non-neoplastic growth of tissue including the epithelial layer
-pleomorphism, hyper chromatism, and loss of normal spatial orientation
-could be a sign of precancerous conditions
What type of keratinized cell is present?
gingival parakeratosis (nucleus retained in the stratum corneum)
What type of keratinized cell is present?
gingival hyperkeratinization (very thick stratum corneum)
What is occuring in this histological slide of buccal lining mucosa?
acanthosis and parakeratosis
(nuclei retained all the way at the top and there is a lack of cellular attachment seen with lack of epithelium rete pegs)
What is seen in this histological slide of buccal lining mucosa
parakeratosis and hyperkeratosis
(nuclei retained at the top and the layer is signicantly thickened)
what is seen in these histological slides?
gingival dyskeratosis
-abnormal keratinization below the level of the stratum corneum
-can be an indicator of squamous cell carcinoma
What is seen in this histological slide?
gingival orthokeratosis
What do melanocytes look like?
have dendritic morphology
-long processes
Where are melanocytes at?
basal cell layer
What occurs in melanocytes?
synthesis of melanin pigment granules
(melanosomes)
What do langerhans cells look like?
have dendritic morphology
-look like tennis rackets
Where are langerhans cells located?
in the stratum spinosum
What is the function of langerhans cells?
antigen traps in epithelium that transfer antigen information to CD4 lymphocytes
What do merkel cells look like?
round
What type of cells are these>
melanocytes
What type of cells are these?
langerhans cells
What type of cells are these?
merkel cells
Where are merkel cells located?
basal cell layer
What is a possible function of merkel cells?
tactile sensory function
What do lymphocytes look like?
round
Where are lymphocytes located?
basal and spinous cell layers
What are lymphocytes associated with?
-immune surveillance and antigen message processing
-inflammation- both humoral and cellular response
what type of cells are these?
lymphocytes
What are the layers of the basement membrane?
-basal lamina + lamina reticularis
-lamina lucida
-lamina densa
What are the components of the lamina lucida?
-bullous pemphigoid antigen
-type VII collagen
-BMG-1
-classic laminin
-kalinin
-k-laminin
-entactin
-epiligrin
What are the components of lamina densa?
-type IV collagen
-type VII collagen
-classic laminin
-BMG-1
-fibronectin
-integrins
What are the components of lamina reticularis ?
-reticulin connective tissue
-type I collagen
-type III collagen
-elastin CT
What help to create connections in the basal lamina>
-cadherin proteins
What are proteins that aid in creation of hemidesmosomes in basal lamina?
-bullous pemphigoid antigen 1 and 2
-cadherin
What protein is important in the lamina lucida layer?
type VII collagen
What proteins are important in lamina densa layer?
-type IV and VII collagen
What proteins are important in lamina retiucularis of lamina propria?
type I and III collagen
What are the specialized cell attachments of the oral mucosa membrane?
-desmosome (macula adherens)
-hemidesmosome
-intermediate junction (zonula adherens)
-tight junction (zonula or macula adherens)
-gap functions (communication junction)
What are the protein components of desmosomes?
-E- cadherin
-P-cadherin
-desmoplakin 1 and 2
-evoplakin
-periplakin
-plakoglobin
What cells types are permanent or resident cell population of lamina propria?
-fibroblast
-monocyte -> histiocyte -> macrophage
-basophil -> mast cell
-plasma cell
-endothelial cell
What are the transient of labile cell populations in lamina propria?
-neutrophils
-lymphocytes
What are fibroblasts?
cells the secrete collagen and elastin
What are histiocytes?
cells that are resident precursors of functional macrophages
What are monocytes?
blood-borne precursors of functional macrophages
What are macrophages?
phagocytic cell capable of antigen processing
What are mast cells?
cells that secrete inflammatory mediators (histamine and heparin)
What are plasma cells?
cells that make immunoglobins (antibodies)
What are neutrophils?
phagocytic cells capable of neutralizing antigens or killing bacteria
What are lymphocytes?
humoral and cell mediated immune response cells
What is the endothelial?
cells that are lining blood and lymphatic vessels
What is the sulcular epithelium?
epithelial cells located in the sulcus
What is junctional epithelium?
epithelium attached to the tooth
-remanent of inner enamel epithelium
what causes the attachment loss seen in periodontal disease?
the moving of the junctional epithelium moving apically
-create a larger sulcus
Does everyone have the same amount of alveolar and attached gingiva?
no, there is a lot of anatomical variation that can occur with different amounts of alevolar and attached gingiva
What are filiform papillae?
hair like papillae
-most numerous
-highly keratinized
-found over the entire dorsal surface of the tongue
What are fungiform papillae?
-fungus like papillae
-small round, red surface projections
-may contain taste buds
-commonly found at the tip of the tongue and
What is this?
filiform papillae
What is this?
fungiform papillae
What are foliate papillae?
-leaf like papillae
-may contain taste buds
-contain lymphoid nodules with germinal centers
-forms part of waldeyer’s ring
-located on posterior lateral margin of tongue
What is this?
foliate papillae
What are circumvallate papillae?
-walled papillae
-generally 6-8 in number
-lightly keratinized
-located just anterior to the sulcus terminalis on the posterior of tongue
-papillae sulcus is cleared of taste stimuli by serous salivary glands of von Ebner
What taste stimuli are circumvallate most sensitive to ?
bitter compounds
What taste stimuli are fungiform papillae most sensitive to?
salty and sweet
What taste stimuli are foliate papillae most sensitive to?
sweet
What are taste cells?
specialized epithelial cells (neuroepithelial)
What nerve supplies taste to the anterior 2/3s of the tongue?
facial nerve via the chorda tympani
What nerve supplies taste to the posterior 1/3 of the tongue?
glossopharyngeal nerve
What nerve supplies taste to the soft palate?
facial nerve via the greater petrosal branch
What nerve supplies taste to the walls of pharnyx and epiglottis?
vagus nerve
Where do taste fibers of all three nerves converge in?
in the tractus solitarius in the brain stem
wat is this?
drug induced lichenoid reaction
what is lichen planus?
unknown etiology
-T-lymphocyte infiltrates with Langerhans cell hyperplasia are charactertistic
-cell mediated immune injury to basal cell is suspected
What is this?
lichen planus
What is this?
candidiasis
What is this?
atrophic candidiasis
What is this?
fissured tongue and possible focal epithelial hyperplasia
What is this?
hairy tongue
What is this?
geographic tongue
What is hyperkeratosis?
thickening of the stratum corneum, often with aberrant keratinization
What is leukoplakia?
white plaque of the oral mucosa membranes that cannot be removed by scraping and cannot be classified histologically as another disease entity
What should leukoplakia be considered?
precancerous until proven otherwise
what percent of all cancers is oral cancer?
3%
What group of people have the highest incidence of squamous cell carcinoma?
middle-aged african american males
What is the overall male-to-female gender ratio of occurrence of SCAA?
3:1
What is the most common site for oral SCCA?
posterior lateral border of the tongue
-floor of mouth and ventral tongue surface are also common sites
What have strong relationships with SCAA?
-tobacco smoking
-chewing tobacco
-alcohol consumption
-phenol exposure
-oncogenic viruses (HPV)
-immunosuppresion (HIV)
-oncogenes and tumor suppressor genes
what are common histopathology of SCCA?
-lesion from dysplastic surface that have nuclear pleomorphism
-invasive islands and cords of malignant squamous epithelial cells
-often strong inflammatory or immune cell responses (necrosis may be present)
-abnormal production of keratin (keratin pearls)
What is Mucosal pemphigoid?
-autoimmune disease
-epiligrin in lamina lucida
-linear accumulation of IgG and C3 along basement membrane
Who does mucosal pemphigoid affect most commonly?
older adults in the 50-60 year old range
-females more often affected than males 2:1
What can be seen in the eyes of patients with mucosal pemphigoid?
scarring in the conjuctiva
(cicatricial)
What is ectodermal dysplasia?
syndrome involving abnormal or lack of development of ectodermal structures such as hair, eyebrows, eyelashes, and teeth
What is peripheral ossifiying fibroma?
lesion that represents the maturation of pyogenic granuloma
where does peripheral ossifying fibroma mostly occur?
exclusively occurs on the gingiva
Who is mostly affected by peripheral ossifying fibroma?
teenagers and young adults with peak prevalance between ages of 10-19 years olf
-60-65% occurs in females
What does histology of peripheral ossifying fibroma appear like?
-islands of calcified material (from periosteum)
What is the recommended treatment of peripheral ossifying fibroma?
surgical excision
-lesion can occur again if excision is not extensive and complete
what is seen?
peripheral ossifying fibroma
