Plasma Derived Mediators of Inflammation Flashcards
What are chemical mediators of inflammation?
Substances which act to initiate and/or enhance an inflammatory reaction
Activate cells by binding specific receptors, recruit cells to sites of injury, stimulate the release of additional mediators
Ie. Bradykinin, thrombin, fibrin, nitric oxide, serotonin, histamine
Chemical mediators are __________ lived and are a ______________ phenomenon
Short, controlled
Redundancy of chemical mediators provides ___________________
Amplification
How are chemical mediators turned off?
Intrinsic mechanisms within the mediators themselves
What is the most important and potent chemical mediator in the kinin family?
Bradykinin
What are the two types of chemical mediators of inflammation?
Plasma- or cell-derived
What are some examples of cell-derived and plasma derived molecules that increase the adherence of WBCs to a vascular wall?
- Plasma Derived = Thrombin
- Cell Derived = LTB4, IL-1, PAF
What are opsonins?
Naturally occurring proteins which coat bacterium for destruction by phagocytes
Ie. C3B and IgG
What are examples of opsonins?
IgG and C3b
What is clotting factor XII also known as?
Hageman Factor
What plasma derived system of inflammation activates bradykinin?
Coagulation system (Hageman Factor XII)
What activates clotting factor XII in the kinin system of inflammation?
Bumping into collagen, basement membrane, tissue protein, negatively charged surfaces (things that shouldn’t be in blood)
What plasma-derived systems of inflammatory mediation does clotting factor XII (Hageman factor) stimulate?
Bradykinin (kinin system) and prothrombin (coagulation cascade)
What does bradykinin stimulate and bind to?
Nociceptors for pain and binds to endothelium to increase vasodilation and increase vascular permeability
Which plasma derived mediator of inflammation is chiefly responsible for a pain response?
Bradykinin
What are three examples of plasma mediated systems of inflammation?
Kinin system, complement system, and coagulation system
What three ways is the complement system of inflammation activated?
Classic pathway (Antigen/Antibody interaction)
Alternative pathway (Lipopolysaccharide/Lipid A of gram negative bacteria)
Mannose pathway (Increased mannose on microbial surfaces)
What is the classic pathway of plasma mediated inflammation?
Antigen-antibody interaction
What is the alternative pathway of plasma mediated inflammation?
Lipopolysaccharide and lipid A are recognized on gram negative bacteria and indicate infection
What is the mannose binding pathway of plasma mediated inflammation?
Increased levels of mannose on microbial surfaces are detected
What are the four main plasma-derived chemical mediators of inflammation procured by the complement system of inflammation?
C3a
C5a
C3b
C5b-C9
What is the function of C3a?
Vasodilation and increased vascular permeability
What is the function of C5a?
Vasodilation and increased vascular permeability
Plasma-derived chemotactic agent and activation of arachidonic acid metabolism
What is the function of C3b?
Opsoninization for phagocytes
What is the function of C5b-C9?
Membrane attack complex to punch holes in bacteria
What molecules produced by the complement system are anaphylatoxins implicated in type I hypersensitivity reactions?
C3a, C5a
What does the coagulation cascade result in?
Blood-clot formation
What is the proenzyme of thrombin?
Prothrombin
What enzyme activates fibrinogen ——> fibrin?
Thrombin
What enzyme activates plasminogen ——> plasmin?
TPA (Tissue plasminogen activator)
What enzyme breaks down fibrin clots?
Plasmin
What protein is involved in creating clots?
Fibrin
What is the function of thrombin?
Activates fibrinogen to fibrin
Increases vascular permeability
Increases WBC adherence to endothelium (for clot formation)
Increases fibroblast proliferation (for clot formation)
What is the function of fibrin split products?
Increased vascular permeability
What is the function of plasmin?
Breaks down fibrin blood clots
Cleaves C3 to form C3a and C3b to turn on the compliment system
What plasma-mediated system of inflammation is turned on by plasmin from the coagulation cascade?
Complement system
What can be given to help clear a blood clot causing an ischemic stroke?
TPA injection
