Chemical Mediators of Inflammation Flashcards
Chemical mediators of inflammation can be ________ or _______.
cell derived; plasma-protein derived
Histamine functions by ________.
dilating arterioles and contracting endothelial cells
Serotonin leads to _______.
vasoconstriction to aid in clotting (it is present in platelet granules)
Arachidonic acid is derived from _________.
membrane lipids (cleaved by phospholipase)
Arachidonic acid is catalyzed by __________, an enzyme inhibited by aspirin and other NSAIDs.
cyclooxygenase (leading to thromboxanes and prostaglandins) and lipoxygenase (resulting in leukotrienes and lipoxins)
Glucocorticords inhibit the _______ of the prostaglandin pathway.
phospholipase that produces arachidonic acid
______ stimulates the growth and function of T cells.
IL-12
What is the first enzyme in the lipoxin/leukotriene pathway?
5-lipoxygenase
Lipoxins ___________.
antagonize leukotrienes and act as anti-inflammatory molecules
Leukotrienes serve as ____________.
chemotactic agents for neutrophils and inducers of vascular permeability
Platelet-activating factor ____________.
is also derived from membranes (by phospholipases) that induces platelet aggregation, bronchoconstriction, vascular permeability, vasodilation
IL-1 and TNF, released by macrophages in acute inflammation, stimulate ________.
endothelial activation, systemic effects of inflammation (fever), and T cell activation
In addition to vasodilation, NO also antagonizes ______.
platelet activation
The initiating factor in the complement cascade is ______.
C3 convertase activation (which cleaves C3 into C3a and C3b)
Complement can be activated by ________.
1) classical (antigen-antibody complexes)
2) pathogen surfaces
3) mannose-binding lectin (lectin binds to microbial mannose)
C3b binds to C3 convertase to become ______.
C5
In the plasma protein mediator system, factor XII (the Hageman factor) activates the _____ system.
kinin (leads to increased vascular permeability)
List some anti-inflammatory factors.
lipoxins, C1 inhibitors, IL-10, and TGF-beta
Mast cells release histamine in response to __________.
IgE; mechanical or thermal trauma; neuropeptides; cytokines; IL-1 and IL-8
The two important chronic-inflammation mediators are ______.
IL-12 and IFN-gamma
NO functions in inflammation by _________.
acting as a free-radical, mediating vasodilation, antagonizing platelet aggregation, and reducing leukocyte recruitment
Alpha-1-antitrypsin inhibits _______ and alpha-2-macroglobulin inhibits __________.
elastase released by neutrophils; many proteases, including collagenase
Neuropeptides are particularly active in _______, and include ________, a polypeptide that stimulates inflammation in epithelial and immune cells.
the lungs and GI tract; Substance P
C3b binds to ______ and initiates _____.
C3 convertase; conversion of C5 to C5b (which activates the MAC) and C5a, a chemotactic and anaphylatic signal
Bradykinin leads to __________.
increased vascular permeability, dilation, and pain
Factor XII activates the __________.
clotting cascade
_____ down regulates macrophages.
IL-10
