inflammation 2 Flashcards
leukocyte extravasation
margination, rolling and adhesion
transmigration
migration
migration, rolling and adhesion
in normal blood flow endothelium does not catch cell it must be activated by cytokines to do so
blood stasis-helping leukocytes stack up periphery (against vessel wall)
rolling-leukocytes adhere transiently to endothelium, roll until becoming firmly attached to endothelium
neutrophils, monocytes, eosinophils, basophils and lymphocytes-all the same described above
adhesion molecules
selectin-initially low affinity
integrins-initially high affinity
immunoglobulin family receptor
how affinity rolling
mediated by selectin expressed on surface of endothelium and leukocytes
high affinity binding
integrin on leukocytes bind to immunoglobulin family receptor on endothelial cells
genetic-deficiencies in leukocyte adhesion
heritable deficiencies in type and amount of adhesion molecules can inhibit leukocyte transmigration and acute inflammation
this may result in poor inflammatory response to pathogens and dead tissue
causes recurrent infections
transmigration-deficiencies in leukocyte adhesion
leukocyte inserts a pseudopod into the junction between endothelial cells and squeeze through
made possible by adhesion molecules located on leukocytes and endothelial cells
chemotaxis
movement of leukocytes in tissue along a chemical gradient
exogenous products-bacteria
endogenous products-complement system component (C5a, leukotrienes B4 and cytokines)
how do cells move
by extending a filopodia that pulls the back of the cell forward
phagocytosis
recognition and attachment
engulfment
killing or degradation of ingested material
engulfment
pseudopods flow around particle to form a phagosome
phagosome fuses with lysosome in cell creating the pahgolysosome
killing and degradation
reactive oxygen species (ROS)
produced with the lysosome
respiratory burst-rapid oxidative reaction
primary mode of microbial killing
lysosomal enzymes
release of leukocyte products during killing=collateral damage
release of lysosomal enzymes and ROS into extracellular space
cytotoxic release-crystal can puncture the cell during phagocytosis and lead to leakage of enzymes and other leukocyte products
genetic defects in leukocyte function
recurrent infection
inherited defects in leukocyte adhesion (Leukocyte adhesion deficience(LAD))
inherited defects in phagolysosome fusion
inherited defects in microbicidal activity
acquired defects in leukocyte function
bone marrow suppression, decreased production of leukocytes
leukemia, radiation and chemotherapy
