Flashcards in Exam 1 Remington- Cornea Deck (123)
What does corneal puncture do?
Stimulates BM adhesion
Epithelial replacement is _______
Where does cell division occur in the corneal epithelium?
The basal cells in the corneal epithelium is replenished from what?
Stem cells in the limbus
How do cells move in epithelial replacement?
Basal layer to wing cell layer to surface, barrier function maintained
Where are surface cells sloughed?
Into tear film
What is the cellular composition of Bowman's layer?
Dense irregular CT, acellular
Bowman's layer is considered a ______ layer
How is Bowman's layer compared to the stroma?
Smaller and less regular fibers than stroma
Bowman's layer is produced _____ and cannot be _______
What is a pterygium?
Conj invades corneal tissue, Bowman's layer is lysed
What is another name for stroma?
What is the cellular composition of stroma?
Regular dense CT, collagen fibrils, fibroblasts, ground substance
What is lamellae?
Bundles of collagen
What is the orientation of lamellae?
Fibers are parallel to surface
What is the extent of fibers for the lamellae?
Fibers extend from limbus to limbus
The _____ stroma has a higher incidence of cross liniing among collagen fibers than ______. Why?
Anterior, posterior. Creates more rigidity helping to maintain corneal curvature
What are two names (same cell) for the cells in stroma?
What junctions are fibroblasts joined by in the stroma?
Gap junctions (can get between cells quickly)
What is ground substance composed of?
Proteoglycans and glycosaminoglycans (GAGs)
What do proteoglycans so?
Increase tensile strength
What are GAGs?
Negatively charged side chains
Are GAGs hydrophilic or hydrophobic?
What do GAGs do?
Maintain component spacing
What is the theory of transparency?
Light should pass straight through the cornea, scattered light causes glare
How are fibers arranged in the theory of transparency?
Fibers arranged in a regular lattice pattern
_____ interference occurs in the theory of transparency
What is reduced in the theory of transparency due to destructive interference?
Light scattering is reduced, as long as the distance between different refractive indices is less than 1/2 wavelength of light
What is the relationship between destructive interference and light scatter?