Corneal Repair Flashcards
What are the roles of corneal integrins?
- facilitates interactions between cells and extracelluar matrix
- matrix assembly
- impact cell adhesion and formation of junctions
- senses changes in the extracelluar environment
- communicated to the cell nucleus by an alteration in the cytoskeleton
What are cytokines?
Signaling molecules.
They are released in health and damaged corneas
What are the 2 roles of cytokines?
- communicates between cells and surrounding tissues
- controls the growth of corneal cells
What are the 3 roles of growth factors?
- promotes proliferation of corneal cells
- induces migration of cells
- maintains corneal transparency
What are the 3 wound healing biomolecules?
- integrins
- cytokines
- growth factors
In which epithelial layer can cells divide?
Basal (through mitosis)
Name the 3 epithelial layers?
And how thick are they?
- basal layer: 1 cell thick
- wing layer:2-3
- surface layer: 2
What is the process of epithelial replacement
Stem cells in the peripheral cornea divide–>new cells move toward the center to become basal cells–>BC move up and become wing cells–>WC move up and become surface cells–>SC shed into tear film–>turn over in 7 days
When there’s a corneal injury what happens to mitosis?
It stops
What’s released if the cornea is damaged?
Growth factors and cytokines
The process of wound healing
- mitosis stops
- growth factors and cytokines are released
- hemidesmosomes dissemble along the wound edge
- this changes the cytoskeleton which causes cells to migrate and cover the wound
- you get adhesion molecules
- –epithelial sheet adheres to basement membrane
- the defect is covered by a single layer of cells and junctions are formed between the neighboring cell
- mitosis resumes and normal cell density is reached
- hemidesmosomes replace biochemical bonds holding basal cells
Cell migration requires control of what 3 things
And what do these preserve
- hemidesmosomes
- cytoskeleton structure
- cell-matrix adhesion
The structural integrity of epithelial sheet
How long does it take small lesions of the epithelium to heal?
24-48 hours
How long does it take if the basement membrane of the epithelium is damaged?
Several months for normal hemidesmosomes
T/F: the epithelium is usually scar free
True
During recurrent corneal erosion the corneal epithelium sloughs off either ___ or ___
Continually or periodically