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Flashcards in Acute inflammation 1 Deck (28)
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1

what is inflammation?

local physiological response to tissue injury

2

what does the inflammatory response affect?

-a complex reaction in vascularised connective tissue
• Reaction of blood vessels which leads to accumulation of fluid and leucocytes in extravascular tissues

3

what does inflammation serve to do?

- to destroy, dilute or wall off the injurious agent
•The inflammatory response is closely intertwined with the process of repair

4

what type of response is inflammation?

protective response

5

what would happen in the absence of inflammation?

-Wounds and injured organs would never heal
- Infections would go unchecked

6

in what ways can inflammation and repair be potentially harmful?

-Life-threatening hypersensitivity reactions
- Chronic inflammatory diseases eg rheumatoid arthritis and Crohn’s disease
-Repair by fibrosis may lead to problems such as disfiguring scars

7

what are the two types of inflammation?

-acute
-chronic

8

what is acute inflammation?

the initial rapid and often short-lived series of tissue reactions to injury

9

what is chronic inflammation?

the subsequent and often prolonged tissue reactions following the initial response

10

what are the 5 principal causes of acute inflammation?

1) Infections- viruses
2) Hypersensitivity- excessive/inappropriate immune reaction which damages tissue)
3)physical agents- trauma
4)Irritant and corrosive chemicals - acid
5) Foreign bodies- dirt

11

what are the physical characteristics of inflammation?

1) Redness (rubor)- dilation of small blood vessels
2) Heat (calor) -increased blood flow
3) Swelling - accumulation of fluid in the extravascular space
4) pain (dolor) -stretching and distortion of tissues caused by increased fluid. Various chemical mediators, including bradykinin are known to produce pain
5) Loss of function- movement is inhibited by pain

12

what are processes of involved in initial rapid reaction of tissue?

1) i) vasodilatation
ii) Increased permeability of blood vessels
2) exudative and cellular phase

13

what happens during vasodilatation?

Results in increased blood flow thus heat and redness

14

what happens during increased permeability of blood vessels?

• Small blood vessels are lined by a single layer of endothelial cells
• The walls of small vessels act as a microfilter
• Oxygen, carbon dioxide and some nutrients transfer across the wall by diffusion
• The main transfer of fluid and solutes is by ultrafiltration as described by Starling

15

what happens during increased vascular permeability -the formation of endothelial gaps in venules?

• Increased vascular permeability is brought about
by chemical mediators including histamine, bradykinin
• Leakage of fluid is confined to POST CAPILLARY VENULES • Gaps in venules are largely intercellular
• Endothelial cells contain contractile proteins, when stimulated by chemical mediators they pull open transient pores
• Endothelial cells are NOT damaged in this process

16

what are the causes of increased vascular permeability?

-Immediate transient -->chemical mediators e.g. histamine
-Immediate sustained
--> severe direct vascular injury
-delayed prolonged
--> endothelial cell injury e.g. X-rays

17

what is the net increase in extravascular fluid called?

oedema

18

what is the fluid exudate?

• Proteins including immunoglobulins, important in destruction of invading organisms
• Fibrinogen  Fibrin on contact with the extracellular matrix (ECM), hence acutely inflamed organ surfaces commonly covered by fibrin
• Exudate is continually being removed by the lymphatics and replaced by new exudate

19

what is the cellular component?

The diagnostic feature of acute inflammation is neutrophil accumulation in the extracellular space

20

what is a neutrophil?

Leukocyte - white blood cell

21

what are the functions of neutrophils?

• Kill microorganisms
• Ingest offending agents
• Degrade necrotic tissue
• Produce chemical mediators
• Produce toxic oxygen radicals
• Produce tissue damaging enzymes

22

How does a neutrophil reach the site of an inflammatory stimulus?

1. Margination-Loss of intravascular fluid and increased plasma viscosity slows flow allowing neutrophils to flow in the plasmatic zone (ONLY in venules)

2)Adhesion-Increased neutrophil adhesion results from interaction between adhesion molecules on its surface and the endothelial surface

3) Transendothelial migration- neutrophils insert pseudopodia into the junctions between endothelial cells. They then cross through the basement membrane and into the extravascular space

23

How do neutrophils find the site of the Inflammatory stimulus?

chemotaxis - locomotion orientated along a chemical gradient

24

what are compounds chemotactic for neutrophils ?

• Bacterial products
• Complement components
• Cytokines
• Products produced by neutrophils themselves

25

what are endogenous chemical mediators ?

chemicals that drive the process of inflammation and cause :
1. Vasodilatation
2. Emigration of neutrophils
3. Chemotaxis
4. Increased vascular permeability
5. Itching and pain

26

what are 3 examples of a chemical mediators?

-Histamine
-chemokines
-lysosomal compounds

27

what are the 4 enzymatic cascade systems in plasma?

1. Complement system
2. Coagulation system 3. Kinin system
4. Fibrinolytic system

28

what breaks down blood clots?

Fibrinollytic