Flashcards in CH2 - Inflammation, Inflammatory Disorders, and Wound Healing Deck (213)
What does inflammation allow?
Allows inflammatory cells, plasma proteins (e.g., complement), and fluid to exit blood vessels and enter the interstitial space
Inflammation is divided into what?
Divided into acute and chronic inflammation
What is inflammation characterized by?
the presence of edema and neutrophils in tissue
Inflammation arises in response to what?
infection (to eliminate pathogen) or tissue necrosis (to clear necrotic debris)
Immediate response with limited specificity
What are the mediators of acute inflammation?
Toll-like receptors, Arachidonic acid (AA) metabolites, Mast cells, Complement, Hageman Factor
Present on cells of the innate immune system (e.g., macrophages and dendritic cells)
How are TLRs attivated?
pathogen-associated molecular patterns (PAMPs) that are commonly shared by microbes, CD14 (a TLR) on macrophages recognizes lipopolysaccharide (a PAMP) on the outer membrane of gram-negative bacteria
TLR activation results in what?
upregulation of NF-kB, a nuclear transcription factor
What does NF-kB do?
activates immune response genes leading to production of multiple immune mediators
TLRs and chronic inflammation?
They are also present on cells of adaptive immunity (e.g., lymphocytes) and play an important role in mediating chronic inflammation.
Arachidonic acid (AA) metabolites
1. AA is released from the phospholipid cell membrane by phospholipase A2 and then acted upon by cyclooxygenase or 5-lipoxygenase.
produces prostaglandins (PG) a. PGI2, PGD2 and PGE2 mediate vasodilation and increased vascular permeability. PGE2 also mediates pain.
produces leukotrienes (LT) a. LTB4 attracts and activates neutrophils. b. LTC4, LTD4 and LTE4 (slow reacting substances of anaphylaxis) mediate vasoconstriction, broncho spasm, and increased vascular permeability.
Where are Mast cells located?
1. Widely distributed throughout connective tissue
How are Mast cells activated?
(1) tissue trauma (2) complement proteins C3a and C5a (3) cross-linking of cell-surface IgE by antigen
Mast cells immediate response is?
involves the release of preformed histamine granules, which mediate vasodilation of arterioles and increased vascular permeability
Mast cells delayed response is?
involves production of arachidonic acid metabolites, particularly leukotrienes.
proinflammatory serum proteins that complement inflammation
Where is complement located?
Circulate as inactive precursors;
Activation of complement occurs via what?
Classical pathway, Alternative pathway, MBL pathway
C1 binds IgG or IgM that is bound to antigen
Microbial products directly activate complement.
Mannose binding lectin pathway
mannose binding lectin (MBL) pathway MBL binds to mannose on microorganisms and activates complement
All pathways of complement result in?
production of C3 convertase (mediates C3?>C3a and C3b, producing C5 convertase (mediates C5?>C5a and C5b)
What forms the MAC?
C5b complexes with C6-C9 to form the membrane attack complex (MAC)
C3a and C5a
(anaphylatoxins)?trigger mast cell degranulation, resulting in histamine-mediated vasodilation and increased vascular permeability
chemotactic for neutrophils
opsonin for phagocytosis