Plasma-derived mediators of inflammation

Question 1

acute inflammatory response is orchestrated by

Answer 1

plasma derived and cell derived chemical mediators

Question 2

plasma-derived mediators are produced mainly in the

Answer 2

liver

Question 3

plasma-derived mediators are present in circulation as

Answer 3

inactive precursors

Question 4

plasma contains 4 major protease cascade systems that contribute to inflammation

Answer 4

1. complement
2. kinin
3. products of coagulation
4. fibrinolysis

Question 5

what is the complement system

Answer 5

a collection of soluble proteins and membrane receptors that function mainly in host defense against microbes and in pathologic inflammatory reactions

Question 6

complement system consists of

Answer 6

more than 20 proteins, some numbered C1 through C9

Question 7

does complement function in innate or adaptive immunity

Answer 7

both

Question 8

in the process of complemetn activation, several celavage products of complement proteins are elaborated that cause

Answer 8

increased vascular permeability, chemotaxia, and opsonization

Question 9

the critical step in complement activation is the

Answer 9

proteolysis of the 3fd component (C3)

Question 10

Cleavage of C3 can occur by one of three pathways

Answer 10

classical, alternative, lectin

Question 11

classical pathway

Answer 11

triggered by fixation of C1 to antibody (IgM, or IgG) that has combined with antigen

Question 12

alternative pathway

Answer 12

can be triggered by microbial surface molecules, complex polysaccharaides, cobra venom, and other substances, in the absence of antibody

Question 13

lectin pathway

Answer 13

plasma mannose-binding lectin binds to CHO on microbes and directly activates C1

Question 14

all three pathways of complement activation lead to the formation of an active enzyme called

Answer 14

the C3 convertase

Question 15

c3 convertase

Answer 15

splits C3 into 2 functionally distinct fragments, C3a and C3b

Question 16

C3a

Answer 16

released

Question 17

C3b

Answer 17

covalently attached to the cell or molecule where complement is being activated; more binds to previously generated fragments to form C5 convertase

Question 18

c5 convertase

Answer 18

cleaves C5 to release C5a and leave C5b attached to the cell surface

Question 19

C5b

Answer 19

binds to the late components C6-C9, culminating in the formation of membrane attack complex

Question 20

MAC composed of

Answer 20

multiple C9 molecules

Question 21

MAC formation of a sufficient number of these large pores or patches causes

Answer 21

an electrolyte imbalance in the target cell, a rapid loss of cell function ensues and lytic death usually results

Question 22

the complement system has 3 main functions

Answer 22

inflamation
opsonization
cell lysis

Question 23

anaphylatoxins

Answer 23

C3a, C5a, C4a are cleavage products of the corresponding complement components that stimulate histamine release from mast cells

Question 24

C5a is also a chemotactic agent for

Answer 24

neutrophils, monocytes, eosinophils, and basophils

Question 25

C5a activates

Answer 25

lipoxygenase pathway of AA metabolism in neutrophils nd monocytes, causing further release of inflammatory mediators

Question 26

C3b and its cleavage product when fixed to a microbial cell wall, act as opsonins and promote

Answer 26

phagocytosis by neutrophils and macrophages; which bear cell surface receptors for the complement fragments

Question 27

MAC is important in

Answer 27

killing of microbes with thin cell walls

Question 28

kinin system is activated by

Answer 28

coagulation factor XII (Hageman factor)

Question 29

what are kinins

Answer 29

vasoactive peptides derived from plasma proteins (kininogens) by the action of specific proteases (kallikreins)

Question 30

the enzyme kallikrein cleaves

Answer 30

a plasma glycoprotien precursor, high-molecular-eight kinogen, to produce bradykinin

Question 31

bradykinin

Answer 31

increases vascular permeability and causes contraction of smooth muscle, dilation of blood vessels, and pain when injected into the skin

Question 32

action of bradykinin

Answer 32

short lived; quickly inactivated by an enzyme called kininase

Question 33

coagulation system is responisble for

Answer 33

conversion of soluble fibrongen into fibrin

Question 34

the ultimate goal of coag system is to

Answer 34

produce thrombin that can convert soluble fibrinogen into fibrin

Question 35

fibrin is an important component of

Answer 35

inflammatory exudates

Question 36

end product of fibrinolytic pathway is

Answer 36

plasmin

Question 37

what is plasmin

Answer 37

a potent proteolytic enzyme with a broad spectrum of activity

Question 38

plasmin is responsible for the

Answer 38

lysis of fibrin into fibrindegradation products, and plasmin acts on fibrin at over 5- sites, breaking down into tiny fibrin degradation products which can easily be removed

Question 39

plasminogen activators are found in

Answer 39

plasma and in many tissues; also present in endothelial cells