Acute Inflammtion Flashcards
Causes of acute inflammation?
Microbial infections Hypersensitivity reactions Physical agents Chemicals Tissue necrosis
What is acute inflammation?
The response of living tissue to injury, initiated to limit tissue damage.
What are the characteristic features of acute inflammation?
Redness Swelling Heat Pain Loss of function
What happens during the vascular phase? Why?
Transient vasoconstriction of arterioles - limit blood loss
Vasodilation of arterioles for increased blood flow
Increased permeability to allow exudation of protein-rich fluid into tissues and slowing of circulation
Which cells is histamine released from?
Mast cells
Basophils
Platelets
What can histamine be released in response to?
Physical damage
Immunological reactions
C3a and C5a
IL-1
What does histamine do?
Increases vascular permeability
Pain
What is Starling’s Law?
Increased hydrostatic pressure, increased fluid flow out of vessel
Increased colloid osmotic pressure of interstitium, increased fluid flow out of vessel
How does arteriolar dilation affect Starling’s Law?
It increases hydrostatic pressure in capillaries so more fluid loss
What has a higher protein content? Exudate or transudate?
Exudate
When is exudate seen?
Inflammation
When is transudate seen?
Fluid loss due to hydrostatic pressure imbalance caused by eg cardiac failure or venous outflow obstruction
What chemical mediators are involved in increasing vascular leakage?
Histamine, leukotrienes
The cytokines IL-1 and TNF
VEGF
What effect do leukotrienes have on vascular leakage?
They cause endothelial contraction
What do cytokines IL-1 and TNF do?
They rearrange the cytoskeleton of which causes gaps in the endothelium
What does VEGF do?
Increases transcytosis across endothelial cytoplasm
What are the four stages of infiltration of neutrophils?
Margination
Rolling
Adhesion
Emigration
How do neutrophils emigrate through the endothelium?
Relaxation of endothelial cells and digestion of basement membrane
What facilitates phagocytosis?
Opsonins Fc and C3b
What is the oxygen dependent killing mechanism by neutrophils?
Production of superoxide radicals and hydrogen peroxide
What are oxygen independent killing mechanisms?
Lysozymes and hydrolases
Bactericidal and permeability increasins protein (BPI)
Cationic proteins (defensins)
Local complications of AI?
Blockage of tubes Loss of fluid (burns) Compression Abscess Pain and swelling
Systemic complications of AI?
Fever Increased leukocytes Septic shock Decreased appetite Weird sleep patterns
Sequalae of AI
Chronic inflammation
Abscess
Resolution
