1. Wound Healing and Repair
Susan and Allison

2. Define the following cell types, give examples:
Labile
Stable
Permanent
Continuously dividing
Epithelia e.g. Skin, GI, cervix, urinary tract
Infrequent divisions but rapid if needed:
Liver, kidney, fibroblasts, smooth muscle cells, endothelial cells, chondrocytes, osteocytes
Never divide in adult life
Cardiac muscle cells, nerve cells, skeletal muscle cells

3. What are the 3 main outcomes following tissue injury?
Regeneration
Scarring
What do we mean by each of the terms?
Restitution of the normal structure and function
Loss of function but structural stability restored

4. Difference between scar and fibrosis is exposure to stimuli (short term vs long term)

5. Regeneration Definition: Restoration of normal structure and function
Can be restored as long as there is minimal damage to tissue architecture and parenchyma cells can proliferate from residual stem cells
2 possible outcomes of regeneration...

6. Regeneration 2 possible outcomes of regeneration: Resolution
Restoration of normal structure and function
Need intact parenchyma or ability to produce parenchymal cells
Labile cells
Compensatory growth
Compensatory growth of cells to restore normal tissue function
Need intact architecture or ability to produce parenchymal cells
Stable cells

7. Fibrous repair
Definition: Healing by deposition of connective tissue (scar)
Occurs when the parenchyma AND stroma are damaged in labile or stable tissues
Associated with loss of function of tissues
What is the main problem with scar tissue?
It does not have the same tensile strength that normal tissue has

8. What 3 main processes are involved fibrosis repair?
Inflammation
Macrophages clear out dead tissue
Granulation tissue
Angiogenesis,
Fibroblasts proliferate/migrate
Scar formation
Connective tissue remodeling
Recovery of tensile strength

9. Free chapter online :

10. What are the 7 steps in cutaneous wound healing?
Formation of a blood clot
Formation of granulation tissue
Cell proliferation and collagen deposition
Scar formation
Wound contraction
Connective tissue remodeling
Recovery of tensile strength

11. What important factors are involved?
Formation of a blood clot (day 1)
Formation of granulation tissue (day 3-5)
Angiogenesis
Cell proliferation and collagen deposition (day 3-10)
Scar formation
Wound contraction
Connective tissue remodeling (day 15+)
Recovery of tensile strength (3 months)
VEGF
TGF-β
PDGF and
MMPs

12. What are the features of granulation tissue?
Hallmarks:
Angiogenesis
Fibroblast proliferation
Other features:
Inflammatory cells
Oedema

13. Types of healing Primary intention: Secondary intention:
Wound is artificially closed e.g. stitches, graft
Secondary intention:
Wound is not closed (spontaneous healing)

14. What are the differences between primary and secondary intention healing? [6]
Initial contraction
Eschar forms
Epidermis regenerates at base
Granulation tissue bed
More contraction
More scarring
Takes longer than primary

15. Local Factors Systemic Factors Infection prolongs inflammatory stage
Mechanical factors
Foreign bodies impairs fibrous repair
Size of wound
Location of wound
Type of wound
Systemic Factors
Metabolic Status
Nutritional Status
Hormones
Circulatory status
What local factors influence wound repair? [6]
What systemic factors influence wound repair? [4]

16. What 3 main things can go wrong with repair?
Inadequate formation
Rupture
Ulceration
Excessive formation
Keloid – scar spreads outside the boundary of the lines
Hypertrophic – excessive scar within boundaries of wound
Proud flesh (granulation tissue)
Formation of contracture
Secondary intention healing may result in excessive contracture