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65 Cards in this Set

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