Path VI Flashcards
What causes chemotaxis, leukocyte recruitment, and activation?
TNF, IL1, chemokines, C2a, C5a, leukotriene B4,
what causes vasodilation?
prostaglandins, NO, histamines
Histamine: what releases it? what does it do?
relased by mast cells, basophils, and platelets
dilates arterioles but constricts larger arteries and bronchioles and incr. vascular permeability
What triggers histamine release?
physical or thermal truama, Ig biding of mast cells, effects of C3a, C5a, neuropeptides, IL1, and IL8
what causes incr. vascular permeability?
histamine, serotonin, C3a nad C5a, bradykinin, leukotrienes C4 D4 and E4, PAF, substance P
What are main mediators of tissue damage?
lysosomal enzymes of leukocytes
reactive oxygen species
nitric oxide
What releases serotonin? What does it do?
enterochrommafin cells and platelets
incr. vascular permability
induce platelet aggregation (less important)
vasodilation
What induces serotonin release?
PAF or trauma of enterochrommafin cells, platelet aggregation. platelet contact w/ collagen, thrombin
what are the maing mediators of fever?
IL1, TNF, IL6, prostaglandins
What factors activate C3 directly? What about C5 and C5a?
lysozome and plasmin can activate C3 directly
kallikrein can activate C5 and C5a directly
What do C3a, C4a, and C5a do?
induce histamine release from mast cells and cause vasodilation.
What does C5a do>
chemotaxin for leukocytes/ activatea arachidonic acid release and lipooxygenase path in tneurophils and macrophages to promote leukotriene production
What does C3b do?
opsonin for neutrophils and macrophages
What is kallikrein?
the active form of prekallikrein, wihch is present in plasma
it activates bradykinin, plasmin, and XIIa (Hageman factor). It also converts C5 to C5 a
What actiaves Kiallikrein?
hageman factor XIIa
What is bradykinin? In what form is it present in the plasma? What activates it?
HMWK= inactive plasma form
it causes smooth muscle contraction, vasodilation, and pain augmentation
it is activated by kallikrein
What is Hageman factor/ factor XIIa?
inactive form in plasma (factor XII)
it activates the clotting cascade/coagulation system, and the kinin system with activates the fibrinolytic system
also activates plasmin?
What factors activate hageman factor?
plasma protein activated by contact with negatively charged surfaces like the basement membranem collegen, elastin bacterial LPS proteolytic enzymes (less important)
What does thrombin do? (4 downstream effects)
converts fibrinogen to fibrin. this produces fibrinopeptides which increase vascular permeability and are chemotactic. it promotes leukocyte adhesion and stimulates fibroblast prolif.
What activates thrombin?
intrinsic and extrinsic clotting cascades
What is factor Xa? Inactive form? what does it do?
Factor X is the inactive form
it activates factor II to IIa.
it increases vasc. permeability
it promotes leukocyte transmigration and emigration
What activates factor X?
clotting cascad via intrisic (factor IX/VIIIa complex) and extrinsic cascades (factor VIIa/tissue factor complex)
What is plasmin? inactive form? what does it do?
inactive form is plasminogen
it lyses fibring clotes to make fibrin split products which increase vascular permeability
it activates C3 to C3a and C3b and activates Factor XII to factor XIIa.