Wound Healing Flashcards

1
Q

When does wound healing NOT result in scarring?

A

Foetus

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2
Q

When does wound healing result in scarring?

A

Late gestation onwards

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3
Q

What cells organise new tissue?

A

Stromal cells

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4
Q

What are the three basic cellular phases of wound healing?

A

Migration, proliferation, differentiation

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5
Q

Outline the process of wound healing

A

Initial acute inflammatory response

Parenchymal functional regeneration

Re-epithelialisation and cell migration

Proliferation of parenchyma and stromal cells

Synthesis of ECM proteins

Remodelling

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6
Q

What are the three classic stages of wound regeneration?

A

Inflammation - ~48h

  • hypoxic + fibrin clot
  • neutrophils and platelets

New tissue formation - ~2-10 days

  • granulation tissue, angiogenesis
  • reepithelialisation under scab, ECM synth

Remodelling - ~1year

  • wound contracts, reepithelialised
  • increased tensile strength, decreased cellularity and vascularity
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7
Q

How does the population of cell change during wound healing?

A

Platelets
Neutrophils
Macrophages
Fibroblasts + Lymphocytes

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8
Q

What occurs in coagulation?

A

Formation of fibrin clot
- platelets and inflammatory cells

Platelet deposition and aggregation

  • platelet degranulation
  • release of PDGF (Platelet derived GF) and TGFb (transforming GF)
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9
Q

What occurs in the inflammatory phase?

A

Neutrophils - matrix phagocytosis + free radical generation to limit infection

Macrophages KEY

  • Debridement and matrix turnover
  • Stimulatory signals/factors

Lymphocytes (later)
- important in early remodelling

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10
Q

What is the role of macrophages in wound healing?

A
Removal of debris 
Cell recruitment and activation 
Phagocytosis 
Angiogenesis -VEGF
Matrix synthesis regulation - GFs, Cytokines (TNFa, IL-1, IFNy),
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11
Q

What is the difference between M1 and M2 macrophages?

A

M1 - proinflammatory, inhibitor of proliferation

M2 - anti-inflammatory, promoter of proliferation

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12
Q

What happens in first part of the the migration phase?

What happens next?

A

Single layer of Keratinocytes migrate under the fibrin clot

Differentiation and stratification of neodermis

Proliferation

Production of VEGF, TNFa (pro inflammatory) PDGF

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13
Q

What cells do you find on the surface of vessels ?

A

Pericytes

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14
Q

What conditions initiate angiogenesis?

A

Inflammation and hypoxia

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15
Q

What is the dominant cell type at the wound edge?

A

Fibroblast

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16
Q

What is the role of fibroblasts ?

A

Synthesise and deposit ECM

Major cell type in remodelling

17
Q

What do fibroblasts differentiate into?

What do they express

A

Myofiblasts and express contractile proteins

Effect wound closure

18
Q

What does excessive healing lead to?

A

Scarring