Wound Healing Flashcards Preview

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Flashcards in Wound Healing Deck (15):
1

inflammation

~48h after injury
hypoxic with fibrin clot
abundant bacteria + platelets
attraction/activation of infiltrating cells
neutrophils - matrix phagocytosis + free radicals
monocytes/macrophages - debridement/matrix turnover

2

new tissue formation

~2-10 days
scab on surface
new blood vessels predominate
migration of epithelial cells
granulation tissue formation
re-epithelialisation

3

remodelling/migration

~1 year
disorganised collagen made by fibroblasts
wound contracted near surface
re-epithelialised wound raised

4

cell recruitment - youngest to oldest

platelets
neutrophils
macrophages
fibroblasts
lymphocytes

5

coagulation

death of some epithelial + dermal cells
damage to collagen fibres in tissue
small vessel rupture - inc vasodilation + permeability
blood released into wound + surrounding tissue
platelet deposition + aggregation
platelets de-granulate (cytokines + growth factors GF)
release PDGF, TGFb (both growth factors), fibronectin
formation of fibrin clot

6

macrophages in wound healing

remove wound debris
cell recruitment + activation
phagocytosis
angiogenesis
matrix synthesis regulation

7

keratinocytes in skin healing

migration/proliferation - integrins + adhesion molecules
ECM production
GF/cytokine production - VEGF (vascular endotheliar growth factor), TNFa, PDGF (platelet derived growth factor)
angiogenesis
release of proteases - dissolve non-viable tissue, penetrate fibrin barrier

8

migration/proliferation

single keratinocyte layer migrates under clot from wound edges across the wound to re-surface the area
during + migration, differentiation + stratification of neo-dermis occurs

9

fibrin clot

platelets + infl cells secrete re-epithelialisation factors
endothelial cell migration into wound

10

angiogenesis

starts as endothelial cell buds
move towards wound space
macrophages + keratinocytes provide angiogenic stimuli
initiated by production of GFs
new vessels start off leaky but integrity increases over time
fibrin clot degraded - proteases made by endothelial cells

11

fibroblasts

replicate in wound
dominant cell type at wound edge
synthesise + deposit ECM

12

myofibroblasts

fibroblasts differentiate into these
contractile function
effect wound closure

13

fibroblasts in connective tissue formation + remodelling

ECM production - serves as scaffold, tensile strength + resilience
GF production
angiogenesis
protease release

14

granulation tissue

established 3-5 days post-injury
fibroblasts, thin walled capillaries + loose ECM
connective tissue accumulates
eventual scar formation
exuberant granulation tissue (proud flesh) normal in the horse

15

scarring process

balance between ECM synthesis + degredation
inflammation is primary driver
prolonged scarring - fibrosis (permanent scar)