Ch3 Acute Inflammation EC Flashcards
What are the cardinal signs of acute inflammation? What are their mediators?
Rubor/Calor - Histamine mediated vasodilation of arterioles
Tumor - Histamine mediated increase in venular permeability (contract endothelial cells)
Dolor - PGE2/Bradykinin
Functio laesa (loss of function)
Is edema fluid an exudate or a transudate?
Transudate (low protein and cell levels)
moves across intact BM
What is margination and what its mechanism?
PMNs pushed to periphery
~liver releases fibrinogen
~RBCs form rouleaux
~forces PMNs into periphery
Describe the rolling of PMNs
Occurs in venules
L-selectin on PMNs binds E&P selectins on endothelial cells
IL-1 and TNF stimulate expression of selectins
L-selectin
selectin ligand on Leukocytes (rolling)
E-selectin and P-selectin
selectins on endothelial cells (rolling)
Weibel-Palade bodies
“glue factory” in endothelial cells
~P-selectin
~vWF
~platelet adhesion molecules
Describe firm adhesion in PMN extravasation
Beta2 integrin activated by C5a and LTB4
Activation of ICAM by IL-1 and TNF
What substances inhibit activation of Beta-2 integrins?
Corticosteroids and Catecholamines
Reason PMN levels increase w/ corticosteroids and during MI - all in blood because they can’t stick
What substances increase activation of Beta-2 integrins?
Endotoxins
causes circulating PMN level to decrease
Delayed separation of umbilical cord
Leukocyte adhesion defect due to selectin deficiency
also see severe gingivitis, poor wound healing, peripheral blood leukocytosis
Transmigration
Movement of PMNs from venules into interstitial space (via type IV collagenase and binding of PECAM-1)
Formation of pus (dilutes toxins and provides opsonins)
Chemotactic mediators
C5a
IL-8
LTB4
Kallikrein
Opsonins
IgG and C3b
Enhance PMN ability to ingest bacteria
Bruton agammaglobinemia
Opsonization defect (lack of IgG) Cannot mature B cells
Describe neutrophil ingestion
Engulf bacteria in phagosomes
Lysosomes combine and empty hydrolytic enzymes (forming phagolysosome)