9 - Pathogenesis of Fibrosis Flashcards
1
Q
Two processes by which repair of injured tissue occurs
A
- Regeneration
- Scarring
2
Q
Regeneration
A
- Growth of cells and tissues to replace lost/damaged structures
- Restoration of normal cells and cell function
3
Q
Scarring
A
- Occurs in response to a wound, inflammation, necrosis
- Organs not able to regenerate
- Deposition of connective tissue
- ECM framework damaged
4
Q
What are factors influencing repair of injured tissue based on
A
- Intrinsic capacity of cells within a tissue to proliferate (or presence of stem cells)
- Labile, stable or permanent tissue
5
Q
Labile
A
- Continuously dividing cells
- e.g. Columnar epithelium GI
tract or hematopoietic cells in bone marrow
6
Q
Stable tissue
A
- Quiescent cells (G0) that proliferate following damage
- e.g. parenchymal cells in liver
7
Q
Permanent tissue
A
- Terminally differentiated cells
- eg. Cardiac myocytes in heart
8
Q
Examples of factors influencing repair of injured tissue
A
- Extent of tissue damage
- Location of injury damage
- Duration of injurious agent
- Infection (delays healing, prolongs inflammation)
- Poor perfusion
- Mechanical stress
9
Q
Requirements of regeneration
A
- Intact tissue scaffold
- Approptiate stem cells to be intact
10
Q
Aberrant wound healing response
A
Fibrosis
11
Q
Fibrosis
A
- Formation of excessive fibrous tissue
- Can adversely affect functional capacity
- eg. fibrosis following MI - compromised contractile function
12
Q
Regulation of healing and repair
A
- Controlled by biochemical factors released in response to cell injury, death or trauma
- Cell responses regulated by intracellular signalling
13
Q
Function of biochemical factors released in response to cell injury cell death, or mechanical trauma
A
- inducing resting cells to enter
cell cycle - Balance of stimulatory or inhibitory factors (determines overall effect)
- Shorten cell cycle
- Decrease rate of cell loss
14
Q
Autocrine
A
Targets self
15
Q
Paracrine
A
Targets nearby
16
Q
Endocrine
A
Targets distant