Oral mucus membranes and pathology Flashcards
Main functions of mucous membranes
are:
- Absorption
- Excretion
- Protection
Masticatory mucosa location
keratinized
• Gingiva
• Hard palate
Lining mucosa location
non-keratinized • Alveolar mucosa • Buccal mucosa • Floor of the mouth • Ventral surface of the tongue • Soft palate
Specialized mucosa location
contains tastet buds
• Dorsal surface of the tongue
layers of the oral mucus membrane
Mucoperiosteum
Defined as a periosteum with a mucosal
surface, i.e., close approximation of mucous membrane
(epithelium and lamina propria) with the periosteum of
bone to form an apparent single layer.
label
organization of the epithelial layer of oral mucosa
Stratum Corneum Stratum Granulosum Stratum Spinosum Stratum Basale (a.k.a.) Stratum Germinativum OR Keratin Layer Granular Cell Layer Spinous Cell Layer Basal Cell Layer
label the epithelial layer
epithelial rete pegs
invagination of epithelial layer into conn tissue papilla
epithelium characterisitics rests on? attatchements of cells? vasculature? cell vs matrix abundance? polarity of cells?
Rests on a basement membrane
Exhibits one or more specialized intercellular
attachments (desmosomes, tonofilaments)
Avascular (gets all nutrients from dermis)
Exhibits a high degree of cellularity and relatively
low volume of extracellular matrix
May exhibit cellular polarity
• Cells exhibit apical, basal, and lateral borders
• Polarity is expressed in the distribution of
cytoplasmic organelles
terms for the stratum corneum regarding form
Orthokeratosis
Parakeratosis
Hyperkeratosis
Dyskeratosis
Orthokeratosis
Orthokeratosis
• Refers to normal keratin formation with clinically
normal presentation.
Parakeratosis
Retention of pyknotic nuclei in the stratum corneum
Hyperkeratosis
• Abnormal thickening of the stratum corneum. May
exhibit aberrant patterns of keratinization.
Dyskeratosis
Abnormal keratinization below the level of the stratum
corneum, i.e., keratinization within the stratum
granulosum and/or stratum spinosum.
terms of the epithelial layer
Acanthosis
Acantholysis
Metaplasia
Dysplasia
Acanthosis
Refers to hyperplasia of the epithelial layer, i.e.,
increase in the number of cells
Acantholysis
• Loss of intercellular attachments between epithelial
cells (keratinocytes)
Metaplasia
• A reversible change in which one adult cell type is replaced by another
e.g., transition of columnar to squamous epithelium in
the respiratory tract as a response to smoking.
Dysplasia
characterized by?
• Refers to a disorderly but non-neoplastic growth of tissue including the epithelial layer.
Characterized by pleomorphism, hyperchromatism, and loss of normal spatial orientation
non-keratinocytes of the oral epithelium
melanocytes
langerhans
merkels
lymphocytes
gingival dyskeratosis of the masticory mucosa could indicate what?
SCC
Melanocyte
• Dendritic morphology (long processes)
• Located in the basal cell layer
• Synthesis of melanin pigment granules
(melanosomes)
Langerhans Cell
• Dendritic morphology
• Located in the stratum spinosum
• Characteristic Langerhans granule (tennis racquet)
• Functions as an antigen trap in epithelium and transfers
antigen information to CD4 lymphocytes
Merkel’s Cell
characterisitc content?
Merkel’s Cell
• Rounded morphology
• Located in the basal cell layer
• Contain characteristic “dense core” granules
• Possibly has tactile sensory functions
Lymphocytes
Lymphocytes
• Rounded morphology
• Found in basal and spinous cell layers
• Associated with immune surveillance and antigen
message processing
• Associated with inflammation – both humoral and
cellular response
organization of the basement membrane
composed of basal lamina (lamina lucida+densa) and lamina reticularis
lamina lucida composition/contents
Bullous Pemphigoid antigen
Type VII collagen (anchoring fibrils)
lamina densa compostion
• Type IV collagen
• Type VII collagen (anchoring fibrils)
fibronectin-can induce cellular polarity
lamina reticularis composition
- Reticulin connective tissue
- Type I collagen
- Type III collagen
- Elastin connective tissue
Relationships of Cytoskeletal Components to the Basal Lamina (attachments)
Cytoplasm of Cell
“tonofilaments”
Hemidesmosome
Bullous Pemphigoid Antigen 1 (BPAG1)
Bullous Pemphigoid Antigen 2 (BPAG2)
Lamina Lucida
BPAG1 & BPAG2
Type VII collagen (Anchoring Fibrils )
Lamina Densa
Type IV Collagen
Type VII Collagen (Anchoring Fibrils )
Fibronectin
Lamina Reticularis of the Lamina Propria Type I Collagen Type III Collagen Reticulin (precursor of elastin) Elastin
how the kinds of attachments work toghether
work to dissipate forces, reduce trauma to a single area
specialized cell attachments found at the mucus mem
Desmosome (Macula Adherens)
Hemidesmosome
Intermediate Junction (Zonula Adherens)
Tight Junction (Zonula or Macula Adherens)
Gap Junction (Communication Junction)
Protein components of desmosomes:
Desmoplakin I & II Evoplakin Periplakin Plakoglobin E-cadherin (Desmoglein) P-cadherin (Desmocolin)
cellular attachments and inflam
can be lost due to inflam
lamina propia cell populations (permanent and transient)
Permanent or Resident Cell Population • Fibroblast • Monocyte>Histiocyte>Macrophage • Basophil>Mast Cell • Plasma Cell • Endothelial Cell Transient or Labile Cell Population • Neutrophils • Lymphocytes
• Fibroblast function at lamina propria
Secrets collagen and elastin
• Histiocyte function at lamina propria
Resident precursor of functional macrophage
Monocyte function at lamina propria
Blood-borne precursor of functional macrophage
Macrophage function at lamina propria
Phagocytic cell capable of antigen processing
Mast Cell function at lamina propria
Secretes inflammatory mediators, e.g., histamine,
heparin
Plasma Cell function at lamina propria
Synthesis of immunoglobulins (antibodies)
Neutrophil function at lamina propria
Phagocytic cell capable of neutralizing antigens and
killing bacteria.
Lymphocyte function at lamina propria
Humoral and cell-mediated immune response
Endothelial function at lamina propria
Lining of blood and lymphatic vessels
epithelium found at the ginigval sulucus
sulcular (gingival), junctional, and keratinized (masticory)
sulcular and junctional separated by the free gingival groove
bottom of pocket=junctional epithelium
junctional epi derived from?
remnant of the primary cuticle
junctional epi in perio disease
calculus and plaque can cause attachment loss and apical migration
label
gingival pigmentation
varies depending on activity of melanocytes
size of the attached gingiva
also variable among pts
lips histology
parakeratinized
capillary loops present
mucus secreting glands
Filiform Papillae
• “Hair-like” papillae • Most numerous • Highly keratinized • Found over the entire dorsal surface of the tongue
Fungiform Papillae
• “Fungus-like” papillae • Small round, red surface projections (color is due to a highly vascular connective tissue core) • May contain taste buds • Commonly found at the tip of the tongue
Foliate Papillae, additional function?
“Leaf-like” papillae
• May contain taste buds
• Contains lymphoid nodules with germinal centers
• Forms part of Waldeyer’s Ring
• Located on the posterior lateral margins of the
tongue
Circumvallate Papillae
• “Walled” papillae • Generally 6-8 in number • Lightly keratinized • Located just anterior to the sulcus terminalis on the posterior dorsal tongue surface • Papillae sulcus is cleared of taste stimuli by serous salivary glands of von Ebner
papillae responses to different tastes
The different papillae respond to all types of taste stimuli
but display bias in their sensitivity:
• Circumvallate papillae tend to be more sensitive to
bitter compounds
• Fungiform papillae respond best to salt and sweet
stimuli
• Foliate papillae show a bias for sweet
von ebners glands
wash away stimuli from the taste cells, located at the base of the papilla
tatse buds
line all papilla except filiform
contain taste cells of neuroepithelial origin
what are taste cells
specialized epithelial cell, i.e.,
neuroepithelial
Nerve supply for taste:
• Anterior 2/3 of tongue: Facial nerve (C-VII) via the
chorda tympani branch
• Posterior 1/3 of tongue: Glossopharyngeal (C-IX)
• Soft Palate: Facial nerve (C-VII) via the greater
petrosal branch
• Walls of the pharynx & epiglottis: Vagus nerve (C-X)
• Taste fibers from all three nerves converge in the
tractus solitarius in the brain ste
coffee coated tongue
due to coffee coating the papillae
lichenoid rxns of the tongue
ulcerative and hypertrophic
many possible stimuli such as drug induced
Lichen Planus etiology? cells involved? result? induced by? treatment?
unknown etiology,
T-lymphocyte infiltrates with Langerhans cell hyperplasia are characteristic.
Consequently, cell-mediated immune injury to basal cells is suspected.
possibly stress induced, treat with steroids to reduce immune response
candidasis
white appearence
fungal infection of the tongue, treat with a anti-fungal agent
can be wiped off but leaves a red spot
usually asymptomatic
fissured tongue/focal hyperplasia
thickened tongue, unknown etiology
connected with xerostomia
hairy tongue
filiform papillae abnormal growth pattern, delayed sheddding of the keratinized layer
can be removed with tongue scrape
geogrpahic tongue
Not considered a patholgy
benign inflammation and degranulation
Hyperkeratosis, precancerous?
Thickening of the stratum corneum, often with aberrant keratinization, is considered precancerous
Leukoplakia
A white plaque of the oral mucous membranes that cannot be removed by scraping and cannot be classified histologically as another disease entity.
Until proven otherwise, leukoplakia should be considered precancerous.
Squamous Cell Carcinoma (SCCA)
Oral cancer accounts for about 3% of all cancers
The highest incidence of SCCA is in middle aged
African-American males
The overall male-to-female gender ratio of occurrence
is 3:1
The most common site for oral SCCA is the posterior
lateral border of the tongue. The floor of the mouth
and ventral tongue surface are also common sites.
Strong relationships exist between SCCA and:
- Tobacco smoking
- Chewing tobacco
- Alcohol consumption
- Phenol exposure
- Oncogenic viruses (Human Papilloma Virus or HPV)
- Immunosuppression (e.g., AIDS)
- Oncogenes and tumor suppressor genes
Histopathology of SCCA is characterized by: arises from? lesions exhibit? what kind of responses occur? pearls?
• The lesion arises from dysplastic surface epithelium
alterations in size, shape, and organization of the cellular components, including nuclear pleomorphism.
• Lesion exhibits invasive islands and cords of malignant squamous epithelial cells.
• There is often a strong inflammatory or immune cell
response to the invading epithelium, and focal areas of necrosis may be present.
• Abnormal production of keratin in the form of “keratin pearls” (i.e., a round focus of concentrically layered keratinized cells) is a frequent finding.
Mucosal Pemphigoid (a.k.a. Benign Mucous Membrane
Pemphigoid or BMMP, or Cicatricial Pemphigoid):
kind of disorder?
Ag?
characterized by?
age group/sex?
additional effect outside the mouth?
- Autoimmune disease=destroys adhesion of epithelim
- Antigen is the adhesin protein epiligrin found in the lamina lucida
- Characterized by linear accumulations of IgG and C3 along the basement membrane
- Affects older adults in the 50-60 year old range
- Females affected more often than males by a ratio of 2:1
- Cicatricial: BMMP involvement of the conjunctiva of the eye results in scarring (symblepharon). eye scarring
Ectodermal Dysplasia:
sweat/salivary glands?
A syndrome involving abnormal or lack of development of ectodermal structures such as hair, eyebrows, eye lashes, and teeth.
hypohydrosis=no sweat glands
lack of salivary glands=xerostomia
Peripheral Ossifying Fibroma cancerous/arises from? occurs where? age group? sex bias? histology? treatment?
Considered to be reactive rather than neoplastic in nature (NOT CANCEROUS). The lesion is thought to represent the maturation of a pyogenic granuloma.
Occurs exclusively on the gingiva.
Predominantly a lesion of teenagers and young adults with peak prevalence between the ages of 10 and 19 yrs.
60% to 65% of cases occur in females.
Histology reveals a gingival mass with islands of calcified material (derived from periosteum).
Recommended treatment is surgical excision
Lesion is likely to recur if excision is not extensive and complete
