Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
46 Cards in this Set
- Front
- Back
|
what is a biochemical mediator?
|
chemical originating either from plasma or cells in response to an injury which acts on targeted cells to initiate a particular response
|
|
|
what inflammatory mediators are circulating in the bloodstream?
|
plasma, cells
|
|
|
what biochemical mediators are from plasma?
|
kinins, complement, activation of clotting system, activation of fibrinolysis
|
|
|
what biochemical mediators are from cells?
|
platelets, tissue mast cells and basophils, inflammatory cells, endothelial cells
|
|
|
what are the four interrelated mediator-producing system activated by Hageman Factor (XII)?
|
Kinin system, complement system, clotting system, fibrinolytic system
|
|
|
Kinin system, complement system, clotting system, fibrinolytic system are activated by what?
|
Hageman factor (XII)
|
|
|
what does the kinin system produce?
|
bradykinin
|
|
|
what is bradykinin?
|
rapidly inactivated by kinases, a potent inflammatory mediator (slow contraction of smooth muscles, dilate systemic vasculature, increase vascular permeability, pain)
|
|
|
what does the kinin system produce from fragments of kininogen?
|
kinin-like peptides from fragments of kiniogen also generated by action of cationic proteases released from neutrophils which may sustain increase in vascular permeability after histamine effect is gone
|
|
|
what do kinin-like peptides do?
|
may sustain increase in vascular permeability after histamine effect is gone
|
|
|
what is the enzyme activator of bradykinin?
|
kallikrein
|
|
|
what is kallikrein?
|
an enzyme activator of bradykinin that is a potent activator of Hageman factor (amplification), chemotactic for neutrophils and macrophages, and converts C5-C5a (activates plasminogen)
|
|
|
what inactivates kinins?
|
enzymes on endothelial cells in lungs (very quickly; seconds) and by proteases (kinases) such as plasma carboxypeptidase N
|
|
|
what are the pathways of the complement system?
|
classical pathway and alternative pathway
|
|
|
what is the classical pathway of the compelemt system?
|
9 serum proteins (components), activated by ICs, some proteases, urate crystals, and polynucleotides (sequential activation)
|
|
|
what is the alternative pathway of the coplement system?
|
5 proteins, activation does not require antibodies, initiated by altered membrane surfaces, collagen, endotoxins, pathogen cell walls, etc
|
|
|
briefly describe the classical pathway of the complement system?
|
antigen-antibody complexes
|
|
|
briefly describe the alternative pathway of the complement system?
|
microbial surfaces (endotoxins) polysaccharides
|
|
|
what else can activate C3 and C5?
|
proteolytic enzymes (plasmin; lysosomal enzymes) in inflammatory exudates
|
|
|
proteolytic enzymes (plasmin; lysosomal enzymes) in inflammatory exudates activate what?
|
C3 and C5
|
|
|
what are C3a and C5a?
|
anaphylotoxins which increase vascular pereability and cause vasodilation mainly by releasing histamine from mast cells
|
|
|
what is C5a?
|
a powerful chemotactic agent for neutrophils, monocytes, eosinophils and basophils, it promotes adhesion of leukocytes to endothelial surfaces
|
|
|
how can C3 be directly converted to C3a?
|
by plasmin, trypsin, bacterial and cellular (neutrophilic) proteases
|
|
|
what does C5a increase expression of?
|
adhesion molecules on leukocytes
|
|
|
C5 can be cleaved to C5a by what?
|
enzymes in neutrophils and platelets
|
|
|
what are the most important complement mediators?
|
C3b, C5-9
|
|
|
what does C3b do?
|
opsonize bacteria and promotes phagocytsosis
|
|
|
what does C5-9 do?
|
promotes cell lysis by forming holes in cell membranes
|
|
|
what is another term for C5-9?
|
Membrane attack complex
|
|
|
what complement mediator opsonizes bacteria and promotes phagocytsosis?
|
C3b
|
|
|
what complement mediator promotes cell lysis by forming holes in cell membranes?
|
C5-9
|
|
|
what forms the membrane attack complex?
|
C5-9
|
|
|
how is the complement system regulated?
|
spontaneous decay of complement complexes, degradation by plasma proteolytic inhibitors (factor 1, carboxypeptidase N), inactivation by binding to specific plasma inhibitors (C1 esterase inhibitor)
|
|
|
what are opsonization reactions in the complement system?
|
opsonins are immunoglobulins or complement fragments adhere to bacteria or inert particles, promote phagocytosis by neutrophils or MPs or C3b binds to bacteria which binds to C3b receptor on phagocytic cells
|
|
|
how does cell lysis occur via the complement system?
|
membrane attack complex (C5b-9) cause holes in membranes causing cell lysis
|
|
|
what happens with complement deficiencies?
|
C3 (Brittany Spaniels), 5, 6, 7, 8 deficiencies result in recurrent infections
|
|
|
what is the clotting system activated by?
|
Hageman factor
|
|
|
what does fibrin do in the clotting system?
|
contains inflammation
|
|
|
what do fibrinopeptides do in the clotting system?
|
increase vascular permeability, chemotactic for neutrophils
|
|
|
where do fibrinopeptides come from in the clotting system?
|
relesed during conversion of fibrinogen to fibrin
|
|
|
what occurs in the fibrinolytic system?
|
plasmin enzymatically splits fibrin (fibrinolysis) and releases fibrin-split products
|
|
|
what do fibrin-split products do?
|
increase vascular permeability, chemotactic for neutrophils
|
|
|
what plasma chemical mediators increase vascular permeability?
|
bradykinin, C3a, C5a, fibrinopeptides, fibrin split products
|
|
|
what plasma chemical mediators cause vasodilation?
|
bradykinin, C3a, C5a, fibrinopeptides, fibrin split products
|
|
|
what plasma chemical mediators cause leukocytes chemotaxis?
|
C3b
|
|
|
what plasma chemical mediators cause cell lysis?
|
C5-9
|
