Acute Inflammation Flashcards
Some causes of inflammation:
- Infection
- Hypersensitivity
- Trauma
- Chemicals
- Necrosis
Hypersensitivity:
Excess immune response due to altered state of immunological responsiveness
Cardinal signals of acute inflammation
Redness - dial action of vessels
Heat - increased blood flow
Swelling - accumulation of fluid
Pain - due to distortion of tissue (chemical mediators released e.g. prostaglandins)
Loss of function
6 stages of inflammation:
• Release of chemical mediators
•Vasodilatation
•Increased vascular permeability
•Fluid accumulation
•Cellular recruitment
•Phagocytosis
Functions of neutrophils:
They can move via:
• Contracting microtubules
• Chemotaxis
They can stick to opsonised microorganisms:
• When bacteria encounter immunoglobulins or complement components, neutrophils can bind to them
They are Phagocytes
What allows neutrophils to marginate?
- Loss of intravascular fluid
- Slowing of flow to the site
Adhesion
Neutrophils adhere to vascular endothelium
Caused by interaction between paired adhesion molecules on the neutrophil and endothelial surfaces
Emigration
When neutrophils pass between endothelial cells through basal lamina and into adventitia
Chemical agents in acute inflammation (4)
Cytokines
Complement
Histamine
Prostaglandins
Role of PAF:
Docks with corresponding receptor on neutrophil and promotes expression molecules allowing firm neutrophil adhesion to endothelial surface
Function of histamine
Causes vascular dilation and permeability
What do prostaglandins cause?
Some cause increased vacular permeability, some cause platelet aggregation
Chemokines
Family of chemicals which attract more white blood cells to site of inflammation
Eg IL-8 attracts neutrophils
Benefits of inflammation:
•Dilution of toxins
•Entry of antibodies
•Stimulation of immune response
Harmful effects of inflammation
Digestion of normal tissue
Swelling
Inappropriate inflammatory response