Flashcards in Acute Inflammation Deck (11):
What are the principle causes of acute inflammation?
1. Microbial infection
2. Hypersensitivity reactions
3. Physical agents
4. Chemical agents
What are physical characteristics of acute inflammation?
+ Red (rubor)
- dilation of blood vessels
+ Hot (calor)
- peripheral increase in temperature
- due to increased blood flow (hyperaemia)
+ Swollen (tumor)
- due mainly to oedema
- some contribution from inflammatory cells
+ Painful/tender (dolor)
- stimulation of nerve endings by pressure and chemical mediators
+ Loss of function
What is the vascular phase of acute inflammation?
Dilation and increased permeability of vessels
What is the exudative phase of acute inflammation?
Fluid and cells escape from permeable venules
What are the features of an exudate?
+ High protein content
+ Proteins include immunoglobulins
- may be important for destruction of invading organisms
+ Fibrinogen > fibrin
- on extravascular contact
- acutely inflamed organ surfaces commonly covered by fibrin
+ High turnover
- continuously removed via lymphatics
Describe the capillaries during acute inflammation
+ Open pre-capillary sphincter
+ Dilation of the arterioles
+ Dilation of the venules
+ Most capillaries full
+ Net flow out
What are features of increased vascular permeability?
+ Produced by chemical mediators including histamine, bradykinin
+ Involves stimulation of endothelial cell cytoskeleton by chemical mediators
+ Confined to post capillary venules
+ Transient, intercellular gaps appear
+ Endothelial cells are not damaged in this way
What are the 4 enzymatic cascade systems of
1. Complement system
2. The Kinin System
3. Coagulation factors
4. Fibrinolytic system
What are the beneficial effects of acute inflammation?
DILUTION OF TOXINS: allows them to be carried away by lymphatics
ENTRY OF ANTIBODIES: due to increased vascular permeability
FIBRIN FORMATION: impedes movement of microorganisms
TRANSPORT OF DRUGS: e.g antibiotics
DELIVERY OF NUTRIENTS AND OXYGEN: aided by increased fluid flow
STIMULATION OF IMMUNE RESPONSE: fluid exudate containing antigens reaches local lymph nodes
What are the harmful effects of acute inflammation?
+ Digestion of normal tissues
+ Swelling e.g laryngeal oedema, brain swelling
+ Inappropriate inflammatory response e.g type I hypersensitivity