In this short tutorial i have described the the basic concepts of inflammation and described vascular changes in Acute inflammation.. Visit http://ilovepathology.com/ for more topics in Pathology!
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Inflammation : Definition Local response of living tissue To any injurious agent
Protective response needed for survival!Can Cause tissue damage by itself!

Historical Aspects

The word inflammation from the Latin inflammare (to set on fire).
Celsus , Roman Writer 1st century AD listed the four signs of inflammation.
He said “rubor et tumor cum calore et dolore” which meant “redness and swelling with heat and pain”
The 5th Sign “Functio leasa” Loss of function Was added by Rudolf Virchow In 19th Century
John Hunter, Scottish surgeon:1793: inflammation is not a disease but just a response!
Elie Metchinkoff: 1880s; A Russian zoologist, Discovered the process of Phagocytosis

The 5 “R”sSteps of inflammatory response

RECOGNITION of the injurious agent
RECRUITMENT of inflammatory cells ( leukocytes)
REMOVAL of the injurious agent
REGULATION ( control) of the inflammatory response
RESOLUTION/REPAIR

ACUTE INFLAMMATION
Vascular Changes
There will be increase in the blood flow
To bring cells and proteins to the site of injury
By vasodilatation & increased vascular permeability

Cellular events
Recruitment of leukocytes
Activation of leukocytes leading to the process of destruction of invaders and production of mediators.
By Phagocytosis

How these stimuli are recognized by the host?
The antigen presenting cells/epithelial cells have RECEPTORS that sense these stimuli

Toll like receptors
Microbial sensors
Present in plasma membrane & endosomes.
Recognize products of bacteria, virus and other pathogens ( almost all!!)
Results in production of mediators of inflammation

Inflammasome
Multiprotein cytoplasmic complex
Recognize products of dead cells
Activation of Caspase1
Activation of IL1 which is the mediator of leukocyte recruitment.
These leukocytes phagocytose & destroy dead cells.

Increased Vascular Permeability

Hallmark of Acute inflammation
There is escape of fluid, blood cells and proteins from the blood vessels into the interstitial tissue
Mechanisms of increased vascular permeability
Contraction of endothelial cells
Direct damage to endothelium/Endothelial injury
Endothelial injury due to leukocytes
Transcytosis