Healing and Repair Flashcards
What is karyorrhexis?
nucleus broken up into multiple pieces (fragmentation)
What is pyknosis?
ink dot nucleus
What is karyolysis?
loss of nucleus
What are the two ways that healing can occur?
regeneration or scar formation
What is regeneration?
replacement of damaged cells by replication of the same cell type
What is scar formation?
replacement of damaged cells by connective tissue
What has to remain intact for cells to regenerate?
the connective tissue scaffolding (ECM)
What is the protein composition of ECM?
Fibrous structural proteins (elastin, collagen)
Hydrated gels (proteoglycan, hyaluronan)
Adhesive glycoproteins
What is the replication status of labile tissues? What are the lost cells replaced by in these tissues?
continuously dividing tissues, lost cells can be replaced by maturation of stem cells or proliferation of mature cells
What is the replication status of stable tissues?
Low or no replication - in G0, but can rapidly divide if stimulated
What are permanent tissues? Give two examples
Terminally differentiated, nonproliferative in postnatal life.
Brain, Heart
What are the sources of EGF?
Activated macrophages, keratinocytes, others
What are the functions of EGF?
Mitogenic for keratinocytes and fibroblasts
Stimulates keratinocyte migration
What are the sources of TGF-alpha?
Activated macrophages, keratinocytes, others
What are the functions of TGF-alpha?
stimulates proliferation of hepatocytes and other epithelial cells
What are the sources of VEGF?
Mesenchymal cells
What are the functions of VEGF?
Stimulates proliferation of endothelial cells
Increases vascular permeability
What are the sources of PDGF?
Platelets, macrophages, endothelial cells, keratinocytes, smooth muscle cells
What are the functions of PDGF?
Chemotactic
Activates and stimulates proliferation of fibroblasts and endothelial cells
Stimulates ECM protein synthesis