Repair 1: Introduction Flashcards
describe the 2 types of repair
Regeneration:
* replacement of Damaged tissue with new cells of same type
* With connective tissue and infrastructure (ECM) intact
* surviving cells must have the capacity to regenrate
Healing by fibrosis (scar):
* Replacement of damaged tissue by granulation tissue —> scar tissue
* due to sever damge of parynchymal organ/ infrastructure + surviving cells are non-dividing
examples of Regenration
- damage to epithelium
- minimal damage affecting only hepatocytes of liver
general factors influencing repair
- Age (- elderly)
- Malnutrition: - ptn & Vit. C –> -collagen synthesis
- Circulatory status (atherosclerosis)
- Drugs: glucocorticoid (cortisol) –> -TGFbeta
- DM & Anemia –
- hormones: Steroids -TGFbeta
Local factors influencing repair
- Extent of tissue damage
- Blood supply to site
- infection & foreign bodies
- site
- Mechanics (torsion & pressure)
- type of tissue
cells that continously prolifrate
Liable cells
Cells that prolifrate only under certain conditions
Stable cells
cells that do not prolifrate
permanent cells
examples of liable cells
- surface epithelium
- Lymphoid cells
- Hemopoeitic cells of bone marrow
Examples of Stable cells
Parenchymal:
* Liver
* kidney
* Pancreas
Mesenchymal:
* endothelium
* fibroblast
* osteoblast
* smooth muscles
examples of Permanent cells
- Skeletal muscles = heal by fibrosis (done by fibrobasts)
- Nerve cells= heal by gliosis (done by astrocytes/glial cells)
Mechanism of repair of Liable cells
regenration
Mechanism of repair of Stable cells
regenration or fibrosis
Stable cells have limited capacity to regenerate except for ____
Hepatocytes (liver)
Mechanism of repair of permanent cells
Fibrosis (skeltal muscle) & Gliosis (nerve cells)
Power of regeneration of liable cells
Short G0
High power
Power of regeneration of stable cells
Long G0, but can enter Mitosis when stimulated by growth factor
Moderate power
Power of regeneration of permanent cells
no regeneration in postnatal life
