wound healing

Question 1

The three phases of wound healing are:

Answer 1

1. inflammatory
2. proliferative
3. remodeling

Question 2

Inflammatory phase of wound healing starts within ____ and can last _____ long.

Answer 2

• starts within 6-8 hours

- can last 3-4 days

Question 3

What are the initial steps of the inflammatory phase of wound healing?

Answer 3

• clot formation and coagulation

Question 4

What is the first that comes to the site of a wound? And what do these do?

Answer 4

Platelets
- release various factors including chemotactics for other platelets, fibroblasts, and immune cells, and interact with fibrin

Question 5

What are the two molecules that help provide a matrix for fibroblasts to rebuild and are essential in the process of clotting and coagulation?

Answer 5

• Fibrin

- fibronectin

Question 6

Name the molecules that help to clear a clot . (THIS MUST OCCUR FOR APPROPRIATE SCAR HEALING)

Answer 6

• plasminogen/plasmin

- metalloproteinases

Question 7

Influx of neutrophils in the inflammatory phase of wound healing occurs in ____ amount of time

Answer 7

• in first 48 hours

Question 8

Inflammatory phase:

- after neutrophils, which arrive in 48 hours, _____ arrive next

Answer 8

• Macrophages (THESE ARE ABSOLUTELY REQUIRED FOR WOUND HEALING!!)

Question 9

What do macrophages do in inflammatory phase of wound healing?

Answer 9

• phagocytose/debride tissue/organisms

- set stage for proliferative stage (via secretion of growth factors–> increasing fibroblasts and ECM development

Question 10

Proliferative stage of wound healing starts _____ and can last ____ long

Answer 10

• day 5-7

- can last up to 1 month long

Question 11

Proliferative phase is initiated by_____

Answer 11

• growth factors (PDGF, TGF, FGF) released by macrophages

Question 12

Reepithelialization begins within _____ (time frame) of proliferative stage initiation:

Answer 12

• within 24 hours

Question 13

Proliferative phase:

• how do keratinocytes get to the wound?
• this leads to ______.

Answer 13

• they leapfrog over each other (lateral mobilization) due to breakdown of desmosomes—> reepithelialization

Question 14

_____ is needed for granulation tissue and is eventually replaced by collagen _____ and eventually collagen ______

Answer 14

• fibronectin
• type III collagen
• type I collagen

Question 15

Wound contraction is mediated by ______

Answer 15

• myofibroblasts

Question 16

Remodeling phase starts at _____ (timeframe) after wound occurs, and can take ______ long

Answer 16

• 1 month

- 1 year!

Question 17

What are the two main things that happen during remodeling phase?

Answer 17

• scar matrix formation

- regression of granulation tissue

Question 18

Remodeling phase:

When granulation tissue regresses, what are the first and last cell types to undergo apoptosis?

Answer 18

• first are endothelial cells

- last are macrophages

Question 19

Scar strength timeline:

Answer 19

• 1 week, 5% strength
• 3 weeks, 20% strength
• 3 months, 50 % strength
• 1 year, 80% strength