histology of the gingiva & gingival CT (lamina propria) Flashcards
3 parts of gingival epithelium
oral, sulcular, junctional
- *epithelium = surface, outer layer that covers the connective tissues (muscles, fibers, etc)
- *all 3 parts are continuous, but different
oral epithelium, strata
-faces oral cavity and extends from gingival margin to mucogingival jxn
- strata basale: contact with CT - capable of cell division
- strata spinosum: spines
* *cells shrink away from one another yet stay in contact via desmosomes - strata granulosum: keratohyalin granules
- strata corneum: keratinized, no nuclei (ortho) or nuclei/incomplete (para)
oral epithelium - connective tissue attachments
- light microscopy: see basement membrane of connective tissue
- CT of lamina propriae (papillae) interdigitates with epithelial rete pegs
- deep numerous epithelial rete pegs: increase surface area for better attachment
- comprised of HEMIDESMOSOMES, lamina lucida, lamina densa, anchoring fibrils, collagen fibers
oral epithelium - CT attachment, on elec microscope
- you see basal lamina epithelial cells and a whitish not as dense layer called lamina lucida
- then a darker line, lamina densa
- *ALL CT FIBERS CONNECT TO LAMINA DENSA
keratinized: ortho vs para
ortho: no nuclei
para: nuclei still in these flattened cells, incomplete keratinization
oral epithelium cell renewal
- *10 days**
1. lose ability to divide
2. produce increasing amounts of protein and keratin
3. lose ability to produce protein, keratin, and energy source
4. becomes dehydrated/flat, lose nuclei, become filled with keratin, maintain desmosomes
5. sloughed away into oral cavity as desmosomes degenerate
other cells of oral epithelium
- melanocytes: make melanin
- langerhans cells: macrophage like cell, regulate tissue function
- merkel cell: tactile sensory
- lymphocyte: inflammatory response
sulcular epithelium
-faces enamel from gingival margin to junctional epithelium
-non keratinized
strata:
1. basale
2. spinosum
3. intermediate - flat cells with nuclei adn organelles
4. superficial - flat cells with organelles, no nuclei, slough off cell into sulcular fluid
**probably 25-30 cells thick
sulcular epithelium - light microscopy, what do you see
- reduced rete pegs (should be smooth in health)
- relatively flat interface
- basement membrane between epithelium and CT
junctional epithelium
- collar like band of epithelium that surrounds the tooth
- attached to both tooth and CT
- few desmosomes between cells, few intercellular spaces
- *thickest at coronal part (15-30 cell layers) and tapers as you go apical
- flat cells with long axis parallel to long axis of tooth
jxnal epithelium - why so few desmosomes
- cells move super fast (4 days to get across)
- very dynamic, always moving and changing
- lots of intercellular space
where is jxnal epithelium
usually overlaps CEJ
where is junctional epithelium thickest
at most coronal part (15-30 cell layers) and tapers as it goes apical
jxnal epithelium - cell renewal
- *4 days**
- mitotic activity in all layers
- cells move towards adn along tooths surface in coronal direction
- migrate at oblique angle, not 90deg like oral epithelium
- continuously attached to tooth
JE - CT attachment
- attaches epithelium to tooth surface (cementum)
- comprised of hemidesmosomes, lamina lucida, and lamina densa
- lamina densa adjacent to tooth
- light microscopy: you see basement membrane, no rete pegs, flat interface
what does JE attach to?
either enamel or cementum — has hemidesomosomes, lamina densa, lamina lucida
(lamina densa adjacent to tooth)
NO DESMOSOMES
gingival connective tissue
- primary cell is fibroblast, which makes the primary protein, collagen
- multiple collagen fibers are long like noodles – provides support/shape of gingiva and attachment of tissue to bone/tooth
collagen
primary protein in gingival connective tissue, 60%
made by fibroblast
gingival fibers - circular, gingivodental, transseptal
- circular: maintain contour and position of marginal gingiva; encircle gingiva in ring like fashion
- gingivodental: from gingiva to tooth, provide gingival support
- transseptal: across septum, from cementum of one tooth to cementum of adjacnet tooth, maintain relationship of adjacent teeth, protects interproximal bone
circular fibers
maintain contour and position of marginal gingiva, encircles gingiva in ring link fashion
gingivodental fibers
from gingiva to tooth, provides gingival support
transseptal fibers
- across septum/interproximal space
- from cementum of one tooth to cementum of next
- maintain relationship of adjacent teeth
- protects interproximal bone
alveolo-gingival fibers
from alveolus to gingiva; attach gingiva to bone
periosteogingival fibers
attach gingiva to bone
transgingival fibers
- like circular, but all intertwined
- secure alignment of teeth in arch
interpapillary fibers
- from tissue in papilla to gingiva
- provide support for interdental gingiva
intercircular fibers
- like circle, but they skip a tooth
- secure alignment of teeth in arch
intergingival fibers
-provide support and countour of attached giingiva
how does papilla get swollen adn enlarged?
extracellular fluid, which cannot get in until collagen fibers start to break down bc they are held so tightly together
gingival crevicular fluid
-from gingival sulcus
-consists of amino acids, plasmids, plasma proteins (including Ab’s), electrolytes
^^^but in a different ratio than serum
-minimal amounts in healthy gingiva bc more structured/ impermeable sulcular epithelium
-increased amounts when inflamed
attachment level (loss)
- histological: epithelium and CT; see where jxnal epithelium ends relative to CEJ but you cannot see exactly where enamel stops
- clinical: based on measurement using fixed reference point–CEJ; distance from CEJ to base of pocket; pocket depth + distance from gingival margin to CEJ
what does it mean if you cannot find CEJ with probe
- jxnal epithelium is at or above CEJ
- this means no clinical attachment loss
lamina propria
gingival connective tissue
