Flashcards in Wound healing Deck (41)
Loading flashcards...
1
What are the stages of wound healing?
Acute inflammation
Parenchymal regeneration (resident funcitonal, not stroma)
Re-epithelialisation and cell migration
Proliferation of parenchyma and stromal cells
ECM protein synthesis
Remodelling (restores function and strength)
2
What are the 3 classic stages of wound healing?
Inflammation (-->48 hours after injury)
New tissue formation (2-10 days)
Remodelling/maturation (1 year +)
3
What is present in the inflammatory phase?
hypoxia +fibrin clot
bacteria
neutrophils
platelets
macrophages
4
What is present during the new tissue formation stage?
surface scab
few inflammatory cells now
new BVs predminate
epithelial migration under scab
5
What is present in the remodelling/maturation phase?
disorganised collagen from fibroblasts
wund contraction near suface
re-epithelialised wound raised
healed region: no appendages
6
What are the 2 main things that occur during new tissue formation?
GT formation
Re-epithelialisation
7
Outline what happens in inflammation
Bleeding
coagulation
platelet activation
complement activation
granulocytes and phagocytes
macrophages and cytokines
8
What are the processes in new tissue formation?
fibroplasia
angiogenesis
re-epithelialisation
ECM synthesis
9
What happens in ECM remodelling?
increased tensile strength
decreased cellularity
decreased vascularity
10
Which cells are present during migration/proliferation stages?
macrophages
lymphocytes
fibroblasts
epithelial cells
endothelial cells
11
What is the main cell involved during remodelling?
fibroblasts
12
Outline the order of cell recruitment
Platelets --> neutrophils --> macrophages --> fibroblasts --> lymphocytes
13
What happens leading up to coagulation?
death of some epithelial and ermal cells
damage to collagenous fibres in tissue
small vessel rupture
release of blood into wound and surrounding tissue
voagulation
14
What happens in coagulation?
platelet deposition and aggregation
platelet degranulation
release PDGF, TGFb, fibronectin
Formation of a fibrin clot
15
When are lympocytes present?
late inflammation (recruited later)
important in early remodelling phase
16
What role do macrophages have in wound healing?
removal of wound debris
cell recruitment and activation
phagocytosis
angiogenesis
matrix synthesis regulation
17
What happens in the initial stage of skin re-epithelialisatin?
Single keratinocyte layer migrates under fibrin clot, from wound edges across wound to re-surface the wound are. During and after migration, differentiation and stratificaion of neo-dermis occurs
18
What do keratinocytes do in wound healing?
migration/proliferation
ECM production
growth factor/cytokine production
angiogenesis
protease release
19
What are some important factors during the migration/proliferation phase?
fribrin
growth factors and cytokines
proteases/MMPs
20
Outline angiogenesis
begin as endothelial cells buds
move toward wound space (along gradients - O2 and VEGF)
macrophages and keratinocytes (epithelial cells) provide the angiogenic stimuli
21
Which are the 2 most important factors for vascular development?
VEGF and PDGF
22
What are pericytes?
contractile cells that wrap around the endothelial cells of capillaries and venules
23
T/F: granulation tissue is usually oedematous.
True
24
Why are fibroblasts important during migration/proliferation?
migrate into wound and replicate
dominant cell type at wound edge
major cell type in remodelling
synthesise and deposit ECM
25
Do fibroblasts differentiate?
Yes --> myofibroblasts and express contractile proteins --> these cells effect wound closure
26
Why are fibroblasts important in CT formation and remodelling? 5
ECM production
GF and cytokine production
Angiogenesis
Protease release
Migration/proliferation
27
When is GT established?
What does it look like?
What does it contain?
within 3-5 days post-injury.
APPEARANCE: Pink, soft granular tissue first appears beneath scab.
CONTAINS fibroblasts, thin walled capillaries and loose ECM.
28
Is proud flesh a normal part of wound healing in the horse?
Yes
29
Outline the phases of remodelling.
Changes in matrix composition over time:
ECM--> collagen --> scar --> fibrosis
30
