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65 Cards in this Set
- Front
- Back
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after a wound occurs a thrombus is formed. What is it formed by and what is its function?
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plasma fibrin and fibronectin form the thrombus. The thrombus is a two-way barrier: it stops things from entering and exiting the wound.
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1. what is the name of the molecule that crosslinks fibronectin? 2. benefit of crosslinked fibronectin?
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1. transglutaminases crosslink fibronectin 2. crosslinked fibronectin provides tensile strength and maintains closure.
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what is the source of early growth factors at the wound site?
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platelets
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what happens to the thrombus late in wound healing?
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the thrombus undergoes proteolysis, then it is penetrated by regenerating epithelium.
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in what sequence does repair and regeneration occur in regards to wound healing?
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repair and regeneration occurs after the inflammatory response
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1. which type of acute inflammation will leave a scar? 2. what is the molecule that lays down the scar?
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1. progressive acute inflammation (macrophage predominant inflammation) 2. collagen
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MMPs are synthesized as zymogens. what activates them?
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already activated MMPs or serine proteases
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what is the main function of neutrophils in a wound?
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neutrophils liquefy and remove necrotic tissue
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fibronectin and cellular debris release chemotactic factors to attract which two cell types?
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macrophages fibroblasts
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what regulates MMP activity?
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MMP activity is regulated by TIMPs. (a series of endogenous tissue inhibitors of metalloproteinases)
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what officially begins when macrophages appear at the site of injury?
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the repair process
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what types of things do macrophages secrete?
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1. collagenase (assists with further liquefaction) 2. growth factors for: - fibroblast proliferation - collagen secretion - neovascularization
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the reaction of vascularized living tissue to local injury is known as________?
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inflammation
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what is the provisional matrix eventually replaced by?
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granulation tissue replaces the provisional matrix
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which cell type actively coordinates the development of granulation tissue? How does it do this?
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macrophages they release cytokines and growth factors
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why is inflammation considered a protective process?
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inflammation: neutralizes the cause of injury rids the body of necrotic tissue
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in the formation of granulation tissue, what cells are myofibroblasts and fibroblasts derived from?
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mesenchymal stem cells
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in the formation of granulation tissue, what cells do capillaries form from?
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capillaries form from the division of existing vessel endothelial cells
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what are some reasons as to why granulation tissue is so highly resistant to bacterial infection?
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granulation tissue is fluid-laden. It is highly vascularized and can therefore supply antibacterial antibodies.
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acute inflammation is characterized by ______________ and lasts how long?
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neutrophils, lasts minutes to a few days
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what are the three main ingredients found in the early matrix of granulation tissue?
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1. proteoglycans 2. glycoproteins 3. type III collagen
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what change do fibroblasts undergo once activated and what do they do?
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fibroblasts change from round to bipolar upon activation. Fibroblasts form collagen and other matrix proteins (such as fibronectin).
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chronic inflammation is characterized by which cell types and lasts how long?
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characterized by macrophages and lymphocytes, lasts days to years
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what is the difference between type I and type III collagen in relation to wound healing?
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Type III collagen is formed first and is weaker. Type I collagen is formed later and has greater tensile strength.
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what is the difference between angiogenesis and vasculogenesis?
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angiogenesis - sprouting of endothelial cells from pre-existing capillary venules. vasculogenesis - blood vessels form de novo from angioblasts.
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What are BFGF (B for Beta) and VFGF and what do they do?
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BFGF and VFGF are potent angiogenic growth factors. They associate with heparan sulfate - this is a crucial feature of angiogenesis.
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how (and in which layer) does the epidermis renew itself?
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how - mitosis where - at the basal layer
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in inflammation what does the following effect have: 1. vasodilation 2. structural changes in microvasculature
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1. increased blood flow 2. allows plasma cells and leukocytes to leave the capillary.
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what is the primary source of regenerating epithelium?
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the hair follicle
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in repair and regeneration, what is the main way that the cell surface is reepithelialized?
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cellular migration is the predominant means of reepithelialization
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when inflammation first begins, what do the blood vessels do (only for a short while)
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vasoconstrict
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which specialized cell is wound contraction dependant on and where is this cell found?
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wound contraction is dependant on the myofibroblast - it is found in granulation tissue
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what is the timeframe for myofibroblast appearance at the wound site?
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myofibroblasts are first seen around day 3 of wound healing. they dissappear as repair progresses and wound has contracted.
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Why is there slowing and stasis in the microvasculature during inflammation?
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because of the increased vascular permeability
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how do myofibroblasts exert their contractile effects?
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by forming tight junctions between myofibroblasts, this binds the cells together in a unit.
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what is the difference between the structure of myofibroblasts and fibroblasts?
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myofibroblasts bind together in a unit, fibroblasts are solitary cells
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what cell types can myofibroblasts be derived from? (3)
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1. pericyte 2. fibroblast 3. stem cell
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1. what is exudate? 2. what does it commonly cause?
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1. protein rich fluid that leaks out of vascular system during inflammation 2. swelling is often due to exudate
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what is the decrease in the size of a wound dependant on?
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the presence of myofibroblasts
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healed wounds have what percentage of the strength of the original unwounded site?
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75% takes about 1 yr to gain this much function.
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approximately what percentage of the original strength is present in a 2 week old wound?
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20%
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what do platelets release when they are activated and what does this molecule facilitate?
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platelets release PDGF, which facilitates adhesion, coagulation, vasoconstriction, repair and clot reabsorption.
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What is the cell? arrives at wound site early and migrates rapidly using small focal adhesions...
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leukocyte
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What is the cell? is rapidly recruited from the bone marrow and invades the wound site within the 1st day...
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neutrophil
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what forms the gaps in the microvasculature?
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CONTRACTION or RETRACTION of endothelial cells
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What is the cell? invades wound site within 1st day, releases granule contents resulting in degradation and destruction of non-viable tissue
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neutrophil
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where do these gaps in microvasculature most commonly occur? (which type of vessel)
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venules
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arrive shortly after neutrophils but persist longer.
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macrophage
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What is the cell? invades wound site within 1st day, releases granule contents resulting in degradation and destruction of non-viable tissue
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neutrophil
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arrive shortly after neutrophils but persist longer.
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macrophage
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What are the two main macrophage actions:
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1. phagocytose debris 2. orchestrate developing granulation tissue by release of cytokines and chemoattractants
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when do the fibroblasts, myofibroblasts, pericytes and smooth muscle cells arrive on the scene? what recruits these cells?
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day 3 to 4. recruited by growth factors and matrix degradation products.
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what is: 1. lamellipodia 2. where are these seen 3. function?
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1. broad, wavelike membrane extensions 2. leukocytes 3. locomotion for migrating leukocytes
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what are: 1. filopodia 2. where seen
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1. narrower and slower than lamellipodia, fingerlike extensions. 2. fibroblasts, smooth muscle cells
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during cell movement the leading edge of the cell interacts with what molecule?
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integrin
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what are the 4 components of the ECM?
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1. collagen fibers 2. elastin fibers 3. ground substance 4. fibronectin
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what is important about fibronectin?
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it can associate with the integrin receptor on the surface of the cell.
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define: basement membrane
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thin, well-defined layers of specialized ECM that separate the cells that synthesize it from the connective tissue.
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what cell types produce basement membranes?
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1. epithelium 2. endothelium 3. adipocytes 4. muscle cells 5. Schwann cells
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which type of collagen is found in the basement membrane?
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collagen type IV
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besides collagen, what is the other predominant ECM molecule that is found in the basement membrane?
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laminin
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what happens when: 1. the equilibrium between collagen deposition and degradation has been restored 2. capillary formation is complete 3. inflammatory cells are diminished
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remodeling begins
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what two things does the leukocyte do in order to increase the avidity of binding in adhesion?
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1. redistributes adhesion molecules to cell surface 2. induces adhesion molecules on endothelium
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what is the class of main digestive enzymes during remodeling?
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metalloproteinases (MMP)- function in matrix degradation during remodeling
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what is the reason for digesting matrix proteins during remodeling?
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degradation allows cellular migration through the stroma
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