Repair and Regeneration Flashcards
What is regeneration?
- Damaged tissue returns to normal.
- Regains specialised function
What is repair?
- The damaged cells cannot be replaced, leads to fibrosis and scarring.
- Loss of specialised function.
What are liable cell populations?
Liable cell populations have:
1) high normal turnover
2) Active stem cell population
3) Excellent regenerative capacity
e.g. Epithelia
What are stable (quiescent cell populations)?
Stable (quiescent) cell populations have:
1) low turnover
2) Turnover can increase if needed
3) good regenerative capacity
e.g. Liver, renal tubules
What are permanent cell populations?
Permanent cell populations :
1) no turnover
2) minimal / no regenerative capacity
e.g. neurons, muscle cells (however research is being conducted in this area)
How is regeneration controlled?
- PROLIFERATION of stem cells covering of defect (cells at edges of defect can proliferate to COVER the injury)
- Contact INHIBITION (once a layer has formed, proliferation is switched off)
- Controlled by growth factors, cell-cell and cell-matrix interactions.
What does regeneration depend on?
- tissue cell kinetics and architecture
- stem cell survival
What is the role of myofibroblasts in granulation tissue formation?
- Myofibroblasts synthesis collagen and extracellular matrix.
- granulation tissue gains myofibrils
- has contractile ability
WOUND CONTRACTION
What are the possible effects of wound contraction - give examples?
1) Oesophageal peptic strictures - scar tissue contracts to form a narrowing of the oesophagus»_space;»swallowing problems
What local factors inhibit healing?
1) infection
2) Haematoma
3) Blood supply
4) foreign bodies
What systemic factors inhibit healing?
1) age
2) drugs
3) anaemia
4) diabetes
5) malnutrition
6) Vit C deficiency
What type of bone heals fractures
Lamellar bone
How does healing occur in the brain?
The supporting tissue in the brain is made of glial cells (not collagen + fibroblasts)
- cyst formation
- Gliosis rather than scarring
