Path

Question 1

WHen is re-epithelialization triggered

Answer 1

whne injury to skin disrupts epidermis resulting in loss of KERITOCYTE-TO-KERITONCYTE contact

Question 2

What is contact inhibition in the proliferative phase of would healing

Answer 2

Keratinocytes migrate across new granulation tissue and replicate (from basale) and this continues until the keratinocytes meet each other (contact inhibition)

Question 3

Basic wound healing stages:

Answer 3

Inflammatory (up to 3 days) - platelets, Macrophages, Neutrophils - clot formation, vasoconstriction, inc. permeability,
Proliferation (3days-5wks) Fibroblasts, myofibroblasts (induced by TGF-B), endothelial cells, kertinocytes, macrophages - deposition of granulation tissue III, angiogenesis, proliferation, would contraction(myofibro)
Remodeling (wk-2yr) - fibroblasts - replacement of type III to type I collagen, inc. tensile strength

Question 4

when does repair happen vs regeneration

Answer 4

repair happens when regenerative stem cells are lost(basal layer cut) or when a tissue lacks regenerative capacity (permanent tissues such as myocardium, skeletal muscle, neurons)

Question 5

What vitmains/minerals are needed during the proliferation stage and why?
ad during the remodeling stage?

Answer 5

Vitamin C and Copper for proliferation. important in hydroxylation of proline/lysine residues
(deficiency? scurvy)

Zinc during remodeling. serves as a cofactor for collagenase converting type III collagen to type I,

Question 6

difference bw hyertrophic and keloid scar

Answer 6

hypertrophic is inc. in type III collagen in parallel fashion. its confined to the borders of original wound. no predisposition

Keloid is majorrrr increase in types I and III collagen. Very disorganized organization and extends beyond wound borders. Inc in people with darker skin