NJDS: Histology - Oral Cavity
Terms
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- What are the anatomical limits of the oral cavity?
- bordered anteriorly by lips and posteriorly by oropharynx.
- What is the oral cavity lined with?
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ORAL MUCOSA
continuous with skin at VERMILLION BORDER
continuous with GI tract at PHARYNX - What are the functions of the oral mucosa?
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1. Protection
barrier to microorgs withstands mechanical trauma.
2. Sensation
receptors for taste, touch, temp, pain, salivation, and certain neuromuscular reflexes
3. Secretion
saliva and sebum (minor)
4. Thermal Regulation
insig. in human, BIG in animals
5. Speech
allows for modification of sound
6. Respiration
conduit for inhalation and exhalation - What are the differences between the oral mucosa and integument?
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1. oral mucosa more deeply colored
2. moist surface
3. NO skin appendages
exception = Fordyce granules
4. Most of oral mucosa is smooth
exceptions = reugae, tongue papilla, linea alba, surface stippling
5. Localized variations in firmness and surface texture - What are the 4 major divisions of the oral cavity?
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1. MASTICATORY MUCOSA
2. LINING MUCOSA
3. SPECIALIZED MUCOSA
4. MUCOSAL JUNCTIONS - MASTICATORY MUCOSA
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-found on gingiva and hard palate
-thick ortho or para keratinized stratifeid SE
-over collagenized CT adhereing to PERIOSTEUM (mucoperiosteum) - LINING MUCOSA
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-found on soft palate, ventral surface of tongue, floor of mouth, lowe part of alveolus, labial and buccal mucosa
-thin, nonkeratinized Stratifed SE
-except lips (ortho or para
-attached to bone or muscle w/ loose collagenous CT
-in some areas contain minor salivary glands, Fordyce granules, adipose tissure - SPECIALIZED MUCOSA
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-thick keratinized or nonkeratinized stratified SE
-forms LINGUAL PAPILLAE
-CT richly vascularized with nerves and blood vessels
-posteriorly has minor salivary glands - What are two types of mucosal junctions?
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1. MUCOCUTANEOUS JUNCTION
2. MUCOGINGIVAL JUNCTION - MUCOCUTANEOUS JUNCTION
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-separates CIRCOCUMORAL SKIN and VERMILLION ZONE of lips
-lip epi. is thin and kertainized, contains prominent vascular RETE PEGS
-makes mucosa look red
-No skin appendages except SEBACEOUS GLANDS - MUCOGINGIVAL JUNCTION
- separates ALVEOLAR MUCOSA from attached GINGIVA
- ALVEOLAR MUCOSA
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-nonkeratinized stratified SE
-loose lamina propria w/ high elastic fiber content - ATTACHED GINGIVA
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-keratinized SSE
-lamina propria w/ many coarse collagen bundles
-attached to periosteum - What are the 5 major tissue components of oral cavity?
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1. ORAL MUCOSA
2. RETE PEGS
3. LAMINA PROPRIA
4. LYNPHOID TISSUE
5. SUBMUCOSA - What are the 4 layers of oral mucosa (from superficial to deep)?
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1. STRATUM CORNEUM
2. STRATUM GRANULOSUM
3. STRATUM SPINOSUM
4. STRATUM BASALE - STRATUM CORNEUM
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-outermost layer
-orthokeratin or parakeratin
-not present in NONkeratinized - STRATUM GRANULOSUM
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-thin layer of flattened cells
-contains keratohyaline granules
-in NONkeratinized granulosum not present - STRATUM INTERMEDIUM and STRATUM SUPERFICIALE
- replaces granuloum and corneum respectively in NONKERATINIZED epithelium
- STRATUM SPINOSUM
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-thickes portion
-cells polyhedral
-have prominent desmosomal attachments around circumference
-contains LANGERHANS CELLS - STRATUM BASALE
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-single layer of cuboidal or columnar cells
-deeply basophilic nuclei
-MITOTICALLY ACTIVE
-gives rise to cells that mature and exfoliate
-contains MELANOCYTES and MERKEL CELLS - Keratinocytes
- all cells that form keratin
- Nonkeratinocytes
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in oral cavity
-Langerhans cells
-Melanocytes
-Merkel Cells - Inflammatory Cells
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migrating leukocytes
-found w/in oral mucosa epi. - RETE PEGS
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-conical projections
-superficial CT
-interdigitate w/ epithelial ridges
-HIGH SURFACE AREA
-resistant to shearing forces
-MANY nerves, capillaries, venules, and lymphatics to supply and drain epi. - LAMINA PROPRIA
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-CT ssupportin epi. and separating it from submucosa and other structures
-very vascular - What are the 2 layers of the LAMINA PROPRIA?
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1. PAPILLARY LAYER
2. RETICULAR LAYER - Papillary Layer
- found among epithelial ridges
- Reticular Layer
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-many irregularly oriented collagen bundles
-more dense than papillary layer
-NO RETICULAR CT - LYMPHOID TISSUE
- scattered lymphocytes and plasma cells in subepi. CT
- SUBMUCOSA
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-in lips, cheeks, and portions of palate
-less dense collagen bundles than in Lamina Propria
-many nerve and vascualr tissue
-minor salivary glands and fat - What are the 5 forms of specialized oral mucosa of the dorsum of the tongue?
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1. TERMINAL SULCUS
2. FILIFORM PAPILLAE
3. FUNGIFORM PAPILLAE
4. FOLIATE PAPILLAE
5. CIRCUMVALLATE PAPILLAE - TERMINAL SULCUS
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-V-shaped groove
-separates body of tongue from tongue base - FILIFORM PAPILLAE
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-many elongated structures at anterior of tongue
-thin CT core with overlying SSE
-tall spire of parakeratin
-NO TASTE BUDS - FUNGIFORM PAPILLAE
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-dome shaped scattered among filiform papillae on anterior of tongue
-thin nonkeratinized SSE
-contains taste buds
-overlies thick CT core
-Partly responsible for SWEET and SALTY tastes - FOLIATE PAPILLAE
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-posterolateral portions of tongue
-not prominent in humans
-prallel array of mucosal ridges
-taste buds found on ridge inclines - CIRCUMVALLATE PAPILLAE
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-8-12
-LARGE
-abut anterior aspect of terminal sulcus
-encircled by deep groove
-glands of von Ebner empty into grooves
-superior aspect lined by keratinized SSE, lateral walls are nonkeratinized SSE
-many tsatebuds on lateral portion
-acid/sour tastes - TASTE BUDS
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-chemoreceptors
-present on tongue, palate, pharynx, and epiglottis
-encompass entire thickness of epi.
-ovoid shape
-use circular taste pore to communicate with oral/pharyngeal cavity - What are the three cells that constitute the taste buds?
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1. Basal Cell
2. Gustatory Cell
3. Sustentacular (supporting) cell - BASAL CELL
- precursor cells
- GUSTATORY CELL
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-TASTE RECEPTOR
-lightly staining - SUSTENTACULAR CELL
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-Supports Gustatory cells
-acts as taste receptor
-dark staining - Which two cells are associated with unmyelinated nerve endings?
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Gustatory and sustentacular cells
-gustatory has stronger relationship with nerve endings - What do gustatory and sustentacular cells have?
- apical microvilli protruding into taste pore
- WALDEYER'S RING
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Lymphoid tissue concentrated in palatine, lingual, and pharyngeal tonsils.
-Forms irregular ring surrounding entrance to oropharynx - What are the 10 age changes in the oral mucosa?
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1. Thinner epithelium
2. Flattening of epithelial ridges
3. Smoother surface
4. Decreased number of filiform papillae
5. Decreased number of Langerhans cells
6. Vascular changes
-lingual varices
7. Increased number of Fordyce granules
8. Decreased cellularity/increased collagen content of LAMINA PROPRIA
9. Salivary gland atrophy
-alteration in taste
-xerostomia
-burning sensation
10. Loss of definition in VERMILLION BORDER