Wound Healing Flashcards
(1i) What is the general pool of baseline cell population called?
transit-ampligying cells (can proliferate, differentiate or undergo cell death)
(2i) Regeneration or restoration of damaged or lost cells or tissue to their original state requires… (2)
- cell proliferation
- intact extra-cellular matrix (ECM scaffold)
this is characteristic of the replacement of skin cells
(1i) Repair involving a combination of regeneration and scar formation by the deposition of collagen requires… (2).
- cell proliferation (parenchyma or stem cells)
- ECM usually damaged, new ECM is deposited
good example of this is hepatocytes after toxic injury from alcohol , whereas ischemic injury to neurons would result mostly in scar formation
(1ii) Describe the events that occur in G0, G1, S, G2 and M.
G0 is quiescent stable cells
G1 growth in mass until restriction point
S chromosome duplication
G2 more cellular growth until restriction point
M Mitosis of cell (G1, S, G2= interphase)
Cells can stay in, or exit the cell cycle as permanent and quiescent cells
(1ii) What cellular molecules are involved in binding for the cell cycle to proceed?
cyclin D must be phosphorylated in order to allow CDK to be active (active kinase of G1->S transition)
cyclin D is controlled by Growth factors like EGF and PDGF as well as growth inhibitors like TFG-b, p53
phosphorylation of retinoblastoma causes the release of E2F and that allows it to be free to transcribe
(2i) Why must our body utilize such a wide variety of growth factors and cytokines in wound healing?
orchestrating populations of cells that act in a synchronous and coordinated manner in the complex process of wound healing
(2ii) What is juxtacrine signaling?
target cell binds a signaling molecule (growth factor) bound to the plasma membrane of the signaling cell
(2i) Epidermal growth factor is secreted by what cells and has what effects?
(includes both EGF and TGF-a) produced by macrophages, inflammatory cells and platelets, which targets epithelial cells and fibroblasts for cellular proliferation
(2i) Platelet derived growth factor is secreted by what cells and has what effects?
produced by platelet alpha granules, macrophages, endothelial cells and fibroblasts which targets hematopoietic cells and fibroblasts with the primary effects as a chemokine for mesenchymal cells and stimulates fibroblast
(2i) Fibroblast growth factor is secreted by what cells and has what effects?
(binding requires FGF bound to ECM) endothelial cells and macrophages target fibroblasts and endothelial cells to cause fibroblast chemotaxis and proliferation and angiogenesis
(2i) Vascular endothelial growth factor is secreted by what cells and has what effects?
produced by leukocytes and fibroblasts and targets endothelial cells for angiogenesis, endothelial cells proliferation and migration and vascular permeability
(2i) Transforming Growth factor-beta growth factor is secreted by what cells and has what effects?
(only receptor type that is serene/threonine kinase) produced by platelets, endothelial cells, fibroblasts and macrophages which targets fibroblasts and leukocytes for primarily fibrogenesis and multiple other opposing effects
(2) Name 3 cytokines important in wound healing.
interferon, interleukin-1 and tumor necrosis factor (TNF)
(2) Which two immune cells communicate via cytokines important in inflammation
T-cell to macrophage (INF gamma)
Macrophage to T-cell (TNF alpha and IL-1)
(2) What is the action of interferon gamma?
activate macrophages and inhibit fibroblasts
