2 Oral Mucosa Overview Flashcards
turnover of epithelium is impacted by what?
keratinization, stratification, and functional demands
what are the 3 types of oral epithelium
- SSNK
- SSPK
- SSK (stratified squamous orthokeretatinized meaning within oral cavity)
what primary cell type gives rise to SSK, SSPK, and SSNK?
keratinocyte
what produces keratin (cytokeratin) proteins?
keratinocyte
what provides structural support and minimizes mechanical stress?
keratin (cytokeratin) proteins
production of ___ results in eosinophilia of cytoplasm
keratin
what contains proteins that aggregate cytokeratin (intermediate filament) produced by stratum granulosum?
keratohyalin granules
what is a single layer of stem cells that self renews and gives rise to amplifying daughter cells (stratum spinosum)
stratum basale
how is stratum basal bound to basement membrane?
hemidesmosomes
stratum basal is found in which types of epithelium?
SSK, SSNK, and SSPK
how do keratinocytes mature?
upward migration and increase in size
turnover time of keratinocyte
dependent on cell proliferation and migration thru layers, ending in desquamation (shedding)
describe this interaction:
during development, the underlying lamina propria (CT) determines the type of epithelium
epithelial-mesenchyme interaction
epithelium can respond to environmental stimuli and alter phenotype resulting in:
adaptive response
what is the time to move from stratum basal to surface?
turnover rate
what are the turnover rate influencing factors?
- proliferation rate
- degree of keratinization
- stratification
- environment/external factors
is non-keratinized or keratinized slower?
keratinized is slower
what are environmental/external factors that affect turnover rate
- chemotherapeutics
- acute inflammation (increase turnover)
- severe inflammation (decrease turnover)
- frictional forces
outcomes of turnover
- desquamation (shedding, exfoliation)
- atrophy (loss of epithelium)
- hyperplasia (increased cell number)
does desquamation prevent bacterial colonization?
YES
type of epithelium and turnover (days) of:
thick skin
SSK
40-55 days
type of epithelium and turnover (days) of:
thin skin
SSK
30-40 days
type of epithelium and turnover (days) of:
hard palate
SSPK
24 days
type of epithelium and turnover (days) of:
buccal
SSNK
14 days
what percentage of each type of mucosa makes of the oral mucosa?
- Lining mucosa - 60%
- Masticatory mucosa - 30%
- Specialized mucosa - 10%
are nuclei present from basal to superficial surface in lining mucosa epithelium?
YES
what epithelium is exposed to frictional masticatory forces of varying degrees?
masticatory mucosa epithelium
do superficial cells lose their nuclei in SSPK of masticatory epithelium?
NO
are nuclei lost in stratum corneum of SSK in masticatory mucosa epithelium?
YES
specialized mucosa is found on what surface of the tongue?
dorsal surface
specialized mucosa is found on what portion of the lip?
vermillion zone
(highly vascularized, no lingual papilla, SSK, and no glands)
key histological feature of oral epithelium surface:
SSNK
- nuclei present
- surface cells appear light, vacuolated, flattened but larger in size
- karatin filaments DISPERSED
- cell layer hydrated
key histological feature of oral epithelium surface:
SSPK
- retained pyknotic nuclei and organelles
- surface appears as flattened (dehydrates)
- kertatin filamens form large BUNDLES
- color change of superficial layer
key histological feature of oral epithelium surface:
SSK (ortho)
- NO nuclei, no organelles in surface layer
- surface layer flattened, dehydrated non-vital cells called squames
- keratin filaments form large BUNDLES on surface
what are epithelium projections into underlying CT that aid in adhesion
rete ridges
what are CT that interdigitates with rete ridges
CT papilla
extent of interdigitation influences the mechanical strength of tissue helps with: ____?
indentification
contents of lamina propria
- ducts of salivary glands
- few sebaceous glands
- capillaries
cell types of lamina propria
- lymphocytes (B and T cells)
- neutrophils
- macrophages
- dendritic cells
- fibroblasts
layers of lamina propria
- papillary: superficial layer - LCT contributes to CT papilla
- reticular: deeper - DICT
submucosa in lamina propria
*may be absent
may be LCT w/ high amounts of adipose or more DICT w/ less adipose
contents of submucosa
adipose, MINOR SALIVARY GLANDS, larger blood vessels and nerve fascicles
what detemines the flexibility of a region
submucosa
what is the region where submucosa is absent and LP attaches directly to periosteum of bone
mucoperiosteum
what are regional variations of oral mucosa
- differences due to functional demands
- extent of epithelial keratinization
- degree of epithelial CT interface
- composition/structures within LP
- presence or absence of submucosa
- overall thickness of mucosa
functions of oral mucosa
- protection against mechanical forces
- physical barrier to microorganism, toxins, and antigens
- provide immunological defense via humoral and cell mediate immune respons
numerous glands are found throughout ___ within oral mucosa
submucosa
function of minor salivary glands
- keep oral mucosa moist
- provide protection
- provide lubrication and buffering capacity
function and appearance of serous glands
- secrete water/serous secretions
- stains very eosinophilic due to proteins in secretion
- aids in taste perception
location of serous glands
- anterior sulcus terminalis of tongue
- circumvallate and foliate lingual papillae
function and appearance of mucous glands
- secrete viscous (mucous) secretions
- appears pale staining with H/E due to mucin glycoproteins
location of mucous glands
- areas requiring lubrication due to functional role in bolus formation
- e.g. soft palate, posterior hard palate, posterior 1/3 of tongue
function of mixed glands
produce mixed secretions where distribution is not equal
location of mixed glands
- areas required to keep epithelium moist associated w/ lining mucosa
- e.g. ventral anterior 2/3 of tongue, labial buccal, pharyngeal, and laryngeal submucosa)
innervations to oral cavity mucosa provide what?
- general sensory (GSA)
- taste (SVA)
- secretomotor (GVE)
sensory receptors in oral mucosa
- nociceptors (pain)
- mechano receptors (touch, pressure, and vibration)
- chemoreceptors (taste)
- thermorecepors (temp)
fiber types for nociceptors
- alpha-delta: free nerve endings, lightly myelinated
- c-fibers: unmyelinated
fiber types for mechanoreceptors
alpha-beta: free or encapsulated nerve endings
fiber types for thermoreceptors
alpha-delta
what are changes in the extent of keratinization that may occur as a physiological ADAPTIVE RESPONSE due to chronic irritation or trauma?
hyperkeratosis
Can hyperkeratosis occur in non-keratinized epithelium?
YES - but often requires biopsy