Tissue Repair Flashcards
What is a labile tissue?
Tissue that continuously turns over from stem cells and proliferation of mature cells.
Skin, gut, bown, etc.
What is a stable tissue?
Tissue with minimal replication. Limited regenerative capacity
Solid organs
What is a permanent tissue?
Terminally differentiated and non proliferative. Repair with scar formation.
Most Neurons and cardiac muscle
2 important properties of stem cells
- Self renew
2. Asymmetric replication
What are the main roles of ECM?
- Mechanical support
- Control of cell proliferation
- Scaffolgd for tissue renewal
- Establish tissue microenvironments.
What percent of a liver can be removed in a living donor transplant?
40-60%
When do scars form?
- Severe or chronic injury and damages parenchymal cells and local connective tissue.
- injury of non-dividing cells.
4 steps of Scar formation
- Angiogenesis
- Mirgation and proliferation of fibroblasts.
- Deposition of CT (granulation tissue)
- Maturation and reorganization into scar tissue
What are the growth factors that promote deposition of CT in scar tissue formation?
PDGF
FGF-2
TGF-B* most important
Come from inflammatory cells (M2 macrophages)
What do MMPs do?
Matrix MetalloProteases
remodel ECM.
When do PMNs, Lymphocytes and Macrophages migrate to a damaged tissue?
PMNs (Neutrophils) during first day
Lymph, Macs: 1-2 weeks
What is first intention healing and how is it different from second intention healing?
1st: Regeneration of Epithelial cells
2nd: Complex repair involving scarring. Much larger and involves wound contraction.
What are some local factors that can influence repair of tissue?
Infection
Trauma
Persistent insult
What are some systemic factors that can influence repair of tissue?
- Nutritional (Vit C, Protein def)
- Metabolic (diabetes, steroids)
- Poor blood flow.
What cell is responsible for Growth Factor Secretion in repair?
Macrophage
