Inflammation and the Acute Inflammatory Response Flashcards Preview

Foundations Test 4 > Inflammation and the Acute Inflammatory Response > Flashcards

Flashcards in Inflammation and the Acute Inflammatory Response Deck (38):
1

Inflammation is basically

Rxn of vascularized tissue to injury

2

Types of edema

Exudate - inflammatory edema...high protein content, specific gravity > 1.020...from increase in blood vessel permeability that is characteristic of inflammation ****contains cellular and chemical mediators critical to inflammation

Transudate - low protein content and specfic gravity < 1.012...filtrate of plasma caused by increase in hydrostatic pressure or decrease in plasma oncotic pressure...no association with vascular permeability

3

Vascular flow change - acute inflammation

Vasodilation...increased blood flow to affected tissue

4

Vascular permeability - acute inflammation

Increases in microvasculature...escape of exudate to injured tissue...blood remaining in vessels is concentrated and moves slows

5

2 mechanisms to increase vascular permeability

Endothelial cell contraction (retraction)
Leukocyte mediated endothelial injury

6

Retraction

Mainly in venules
Endothelial cells shorten, leading to widening of junctions...exudate through gaps
Rapid
Mediated by lots of chemical mediators

7

Leukocyte mediated endothelial injury

Mostly in venules
Leukocytes adhere to endothelial cells and become activate...release toxic substances that cause endothelial injury and detachment of cells from inner wall of blood vessels

Delayed onset

8

Adhesion

When stasis occurs, leukocytes within blood stream move toward inner wall of blood vessels (margination)

Rolling leads to adhesion

Adhesion molecules are mediators that bind...selectins involved in rolling, integrins promote firm adhesion

Modulation of adhesion molecules necessary to promote binding to one another

9

Redistribtuion of adhesion molecules from within cytoplasm to cell surface where they are available for binding example

P-selectin normally bound to Weibel-Palade bodies in endothelial cytoplasm...chemical mediators cause migration to endothelial membrane

10

Induction of adhesion molecule synthesis example

E-selectin...not found within endothelial cells unless induced by chemical mediator of inflammation...not immediately available

11

Increase in binding affinity of adhesion molecules example

LFA-1/ICAm-1 interaction...leukocyte activation leads to conformational changes of adhesion molecules

12

Transmigration across endothelium

Diapedesis

Leuko squeezes through gaps and into tissues...homophilic adhesion to PECAM-1 ...****neutrophil is predominant cell that transmigrates in acute

13

Two types of chemoattractants

Exogenous - from bacteria
Endogenous - produced by injured host

14

Mechanism of chemotractant inducement of movement

Chemoattractant binds receptor on leukocyte membrane...activates intracellular phospholipase C which triggers series of events increased intracellular calcium...causes cross linked of actin...forms pseudopod and moves in direction of density gradient...process of pseudopod formation occurs repeatedly until it reaches sources

15

Phagocytosis steps

Recognition and attachment
Engulfment
Killing

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Recognition - phago

Enhanced by coating of object with opsonins (fragment of IgG and compllement C3b)...opsonins bind to leukocyte

17

Engulfment - phago

FOrms phagosome...lysosomes fuse to form phagolysosome

18

Killing and degradation options

Oxygen dependent killing - consumption of oxygen in phagolysosome causes oxidative burst...involves peroxide-myeloperoxidase-halide system which is covalent insertion of halide into bacterial molecules

Oxygen independent killing - involves other substances in lysosomes that don't need oxygen (BPI, lysozyme, lactoferrin)

Acid hydrolases degrade

19

Vasoactive amines

Histamine and serotonin

20

Histamine

Preformed and immediately available
Found in mast cells
Dilations of arterioles, increase vascular permeability, redistribute P-selectin
Causes some tissue damage

21

Serotonin

Found iwhtin platelet granules...preformed and similar to histamine

22

Complement system

Lyses microorganisms by generating membrane attack complex
C3a and C5a cause vasodilation and increase permeability...also help release histamine from mast cells
C5a - potent chemoattactant and stimulates movement of leukocytes
C3b - opsonin

23

Kinin system

When factor 12 (Hageman factor) of clotting system comes in contact with injured tissue, becomes activated and activates cascade

Bradykinin- increases vascular permeability...contributor to pain
Kallikrein - activates Hageman factor and produces more brady kinin...also chemoattractant

24

Clotting system

Triggered by factor 12

Produces thrombin...binds to protease activated receptors (PARs) on membranes of cells...redistribtuing of P-selectin and production of prostaglandins

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AA metabolites

Phospholipases that have been activated will release AA into cells...metabolized by 1 of 2 pathways

26

Cyclooxygenase pathway

Produces prostaglandins

27

Prostacyclin

PGI2

Vasodilation...inhibits aggregation

28

Thromboxane A

Vasoconstriction and promotes aggregation

29

PGD2 and PGE2

Vasodilation and increased permeability of post-cap venules...PGD2 is chemoattractant for neutrophils

30

Prostaglandins can cause

Pain ad fever

31

Lipooxygenase pathway

Produces leukotrienes and lipoxins

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Leukotriene B4

Chemoattractant

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Leukotriends C4,D4, and E4

Increase permeability
Vasoconstriction
Bronchospasm

34

Lipoxins A4 and B4

INhibit neutrophil chemotaxis and ability of neutrophil to adher to endothelium...terminates

35

Cytokines

Synthesizes by activated leukocytes

36

Interluekin 1

Similar to TNF

Promote leukocyte adhesion
Promote synthesis of prostaglandins and others
Cause fever, loss of app, increased sleep

37

Interleukin 8

Member of chemokines (powerful chemo attractant)...chemotaxis for neutrophils

38

Nitric oxide

SOluble gas released by endothelial and macrophages

Vasodilator
Interacts with Oxygen free rads to produce antimic substances

Inhiits some of cellular events of inflammation and keeps response under control