Corneal Repair

Question 1

Integrins

Answer 1

connects cells and extracellular matrix
forms intercellular junctions
sense change in extracellular environment

Question 2

Cytokines

Answer 2

fascilitate cellular communication between cells and surrounding tissues
control growth of corneal cells

Question 3

Growth Factors

Answer 3

promote proliferation of corneal cells
starts migration of cells
maintains transparency

Question 4

Layers of Epithelium

Answer 4

Surface- 2
Wing- 2-3
Basal- 1

Question 5

Layer for Epithelial Cell Replication

Answer 5

Basal Layer

Question 6

How long is the cell turnover of the epithelium?

Answer 6

7 days

Question 7

Initiate repair of corneal epithelium

Answer 7

growth factors and cytokines

released from damaged cells

Question 8

Change in cytoskeleton during healing

Answer 8

cell shape changes
cells at wound edges develop membrane extensions
cells migrate to cover wound

Question 9

Cell Migration requires….

Answer 9

hemidesmosomes
cytoskeleton structure
cell to matrix adhesion
preserves integrity of epithelium

Question 10

Adhesion Molecules

Answer 10

allow for epithelium to stick to Bowman’s

pulls cells forward to cover wound

Question 11

Prevents Epithelial Hyperplasia during wound healing

Answer 11

apoptosis

Question 12

Healing time of a small lesion

Answer 12

24 - 48 hrs

Question 13

Healing time if basement membrane is damaged

Answer 13

several months

Question 14

Recurrent Corneal Erosion

Answer 14

epithelium sloughs off

from poor adhesion b/t epithelium and basement membrane or b/t BM and stroma

Question 15

Recurrent Corneal Erosion occurs when?

Answer 15

after incomplete healing of abrasion

epithelial basement membrane dystrophy

Question 16

Treating Recurrent Corneal Erosion

Answer 16

artificial tears, antibiotics, bandage

anterior stromal micropuncture, superficial or phototherapeutic keratectomy

Question 17

Bowman’s Layer

Answer 17

acellular
composed of collagen
highly resistant to damage; does not regen

Question 18

Replaces lost Bowman’s cells

Answer 18

stromal scar tissue or epithelium

Question 19

Stroma Composition

Answer 19

collagen fibrils
keratocytes
extracellular ground substance

Question 20

Why is the stroma likely to scar?

Answer 20

new collagen fibers are larger and their organization is not as precise

Question 21

Time frame to heal stroma

Answer 21

months

takes longer for new collagen to get to full strength

Question 22

Descemet’s Membrane

Answer 22

basement membrane of endothelium
made of collagen
produced constantly

Question 23

Where does Descemet’s membrane regenerate from?

Answer 23

stromal keratocytes and endothelium

Question 24

Layers to Endothelium

Answer 24

1

Question 25

Basal part of Endothelium faces.....

Answer 25

Descemet's

Question 26

Apical part of Endothelium faces....

Answer 26

anterior chamber

Question 27

Healing Endothelial Damage

Answer 27

neighboring cells enlarge and flatten to fill in space- loss of density take polyhedral shape increase # of ion pumps