CORNEA Flashcards
What are the 6 layers of the cornea
- Epithelium
- Anterior limiting lamina
- Stroma
- Dua’s layer
- Posterior limiting lamina
- Endothelium
what are the 3 cells in the epithelium
Columnar
wing
squamous
what is the anterior limiting lamina composed of?
fine collagen fibrils arranged haphazardly
what is the function of anterior limiting lamina
creates a smooth surface for basal membrane of epithelium
what is the structure of the collagen fibrils in the corneal stoma and Lammellae and why?
evenly spaced in parallel beds
Lamellae cross each other obliquely, remain parallel to surface
this keeps the surface clean
Function of corneal stroma
Mechanical strength and stability
protection from internal structures
How does cornea maintain transparency
regular arrangement of lamellae act as diffraction gratings
Is Duas layer cellular or acellular and what does that mean
acellular - no cells just collagen
about posterior limiting lamina
can be reformed if damaged
ends at the edge of limbus and marks the poster corneo-limbal function
what is function of posterior limiting lamina
be the basement membrane for the endothelium
what is the function of having endothelium cells have zonular occlusions a their apical edges
prevents passage of fluids between fluids
can cells in endothelium regenerate? what happens?
once damaged they cannot replace themselves
the other cells spread out, to fill gap.
older you get = thinner
about corneal transparency
- Avascular - no swchann cells
- Smooth anterior surface
- corneal hydration is strictly regulated
- Stromal lamellae act as diffraction gratings
Might swchann cells impair transparency of cornea
yes thats why there is none
this will mean the cell is avascular
because cornea is avascular, where does its nutrients come from?
from limbal arcades, the aqueous and tears film
