Acute Inflammation Flashcards
Aidan
What are the causes of acute inflammation?
- Microbial infections.
- Hypersensitivity reactions.
- Physical agents.
- Chemical agents.
What are hypersensitivity reactions?
Allergies.
How to recognise (acute) inflammation?
- Redness.
- Heat.
- Swollen.
- Painful/Tender.
- Loss of function.
What causes the characteristic redness of Acute inflammation?
Dilation of blood vessels.
What causes the characteristic heat of Acute inflammation?
- Peripheral inc. in temperature.
- Due to increased blood flow (hyperaemia).
What causes the characteristic swelling of Acute inflammation?
- Due mainly to oedema.
- Some contribution from inflammatory cells.
What causes the characteristic pain/tenderness of Acute inflammation?
-Stimulation of nerve endings by pressure and chemical mediators.
What is oedema?
Influx of fluid into a tissue that doesn’t normally have as much fluid in it.
What are the phases of acute inflammation?
-Vascular and Exudative phases.
What is the characteristic cell of Acute inflammation?
Neutrophil polymorphs.
What happens in the vascular phase?
Dilation and increased permeability.
What happens in the exudative phase?
Fluid and cells escape from permeable venules.
What is the net flow in a normal blood vessel compared to a blood vessel affected by acute inflammation.
In a normal vessel there is no net flow as fluid leaks in or out.
in acute inflammation there is net flow out as the vessel has increased permeability
What are the features of exudate?
- High protein content.
- Proteins may include immunoglobulins.
- Fibrinogen turns into fibrin.
- High turnover.
Why are immunoglobulins important?
They may be important for the destruction of invading organisms.
When does fibrinogen turn into fibrin and what does this cause?
It changes on extravascular contact and acutely inflamed organ surfaces are commonly covered by fibrin.
What causes the high turnover of exudate?
It is continuously removed by lymphatics.
Differences between exudate and transudate?
- Exudate; net flow out, inc. vascular permeability and high protein content.
- Transudate; Net flow out, normal vasc permeability and low protein content.
What happens with increased vascular permeability?
Stimulation of endothelial cell cytoskeletons causes them to change shape and transient intracellular gaps appear.
What happens to endothelial cells after inflammation has been dealt with?
They return to normal shape after and are not damaged by the process.
How is increased vascular permeability caused?
caused by chemical mediators including; histamine and bradykinin.
What happens to the lymphatic system in inflammation?
- Lymphatics dilated
- Drain fluid from exudate
- Antigens carried to lymph notes + recognised by lymphocytes.
What is the number of lymph nodes in the body?
Varies from person to person but average is 250-300.
What is Lymphangitis?
Inflammation of the lymphatic vessels.
What is Lymphadentis?
Inflammation of the lymph nodes.
What do neutrophils have to do with diagnosing acute inflammation?
Neutrophil accumulation in the extracellular space is the diagnostic feature of acute inflammation.
What do neutrophils do?
- Kill organisms.
- Degrade necrotic tissue.
- Ingest offending agents.
- Produce chemical mediators, toxic oxygen radicals and tissue damaging enzymes.
What are the stages of neutrophils leaving vessels?
1-Magination (beginning to stick).
2-Pavementing (flattening out).
3-Pass between endothelial cells.