Flashcards in Tissue Repair Deck (37):
What is the Parenchyma?
Functional parts of an organ
What is the Stroma?
The structural tissue of organs
What are the causes of Tissue Damage? (6)
Physical and Chemical Agents
What is Diapedesis?
Passage of blood ells through intact walls of the capillaries
Typically accompanies inflammation
What events occur in the Haemostasis Phase?
Release of Pro-Inflammatory mediators
What events occur in the proliferation phase?
Alterations in cell-cell and cell-matrix interactions
Cross-talk between MMPs, integrins and cells
Cytokine and growth factor release
What are MMPs?
Group of enzymes responsible for the degradation of most extracellular matrix proteins
What is ECM?
Collection of extracellular molecules secreted by cells that provides structural and biochemical support to the surrounding cells
Regulates movement and growth of cells
What event occurs during the Remodelling phase?
Fibroblast to myofibroblast differentiation
ECM remodelling and degradation
What are the phases of tissue repair?
What are the fundamentals of inflammation?
Rubor - Redness
Calor - Heat
Dolor - Pain
Tumor - Swelling
Functio laesa - Loss of Function
What is a fibroblast?
Type of cell that synthesises the ECM and collagen, the stroma and plays a critical role in wound healing.
Most common cells of connective tissue
What is PDGF?
Platelet derived growth factor
What is VEGF?
Vascular endothelial growth factor
What is CXCL5?
Platelet Factor 4
Binds with high affinity to heparin
Neutralises heparin like molecules on endothelium
Inhibit local antithrombin activity to promote coagulation
Strong chemoattractant for neutrophils and fibroblasts
What is CCL5?
Chemokine ligand 5
chemotactic for T cells, eosinophils and basophils
What is bFGF?
Basic Fibroblast Growth Factor
What is TGFβ?
Transforming Growth Factor Beta
Cascade causes differentiation, chemotaxis, proliferation, activation of immune cells
What is the function of platelets in tissue repair?
What stage are they involved in?
Formation of Platelet Plug
Release pro-inflammatory mediators
What are the stages of Leukocyte Recruitment?
Integrin Activation by Chemokines
Migration through Endothelium
What is the roll of neutrophils in tissue repair?
Recruited within minutes
What is the respiratory burst?
In neutrophils and macrophages
Intracellular bleach (reactive oxygen species) released to kill engulfed bacteria
Green Enzymes - green discharge
What is the role of Macrophages in Tissue Repair?
Resident macrophages - alveolar macrophages and kupffer cells (liver)
Monocyte derived macrophages
M1 - inflammatory
M2 - removing debris
Produce Nitric Oxide
What is Granulation Tissue?
New connective tissue and microscopic blood vessels hat form on the surfaces of a wound during the healing process.
Typically grows from the base of the wound and is able to fill wounds of any size
What does the outcome of the proliferative phase depend on?
What are Labile cells?
Where are they found?
Reproduce new stem cells to replace functional cells
What are Quiescent cells?
Where are they found?
Stem cells that retain the ability to divide
Enter the cell cycle when activated
Renal tubular epithelium
What are permanent cells?
Where are they found?
Terminally differentiated cells
No proliferative capacity
Damage to these cells leads to scarring
Red blood cells
What are the different pathways for angiogenesis? (2)
Mobilisation of EPCs (endothelial progenitor cells) from bone marrow
Angiogenesis from pre-existing vessels
Driven by VEGF
What substances make up the Extracellular Matrix?
What is the role of each substance?
Collagen - tensile strength
Elastin - elastic stretch and recoil
Proteoglycans - regulate structure and permeability, moderate cell growth, bind growth factors
Adhesive glycoproteins - fibronectin and laminin - cell recognition, adhesion, migration and proliferation
Integrins - major cell surface receptors, mediating cell adhesion to ECM
What types of cels can become myofibroblasts?
What is first intention skin healing?
Focal disruption of the basement membrane and limited loss of epithelial cells
What is skin healing by second intention?
Larger injury than first intension
Edges can't be Brough together, due to tissue loss
Results in large scar and contraction
What are the local factors that delay tissue repair? (7)
Poor blood supply (atherosclerosis)
Infection (and biofilm formation)
What are the systemic factors that delay tissue repair? (9)
Nutritional deficiencies (vitC)
Genetic Disorders (marfans)
How, when and where does fibrosis occur?
Excessive deposition of ECM
During abberant wound healing there is too much collagen production
Lung, liver, cardiac, skin, kidney