acute inflammation Flashcards
Definition of acute inflammation
fundamental response maintaining integrity of organism
dynamic homeostatic mechanism
higher organisms
series of protective changes occurring in living tissue as a response to injury
Cardinal signs of inflammation
rubor - redness calor - heat tumor - swelling dolor - pain loss of function all of these explained by the sequence of Pathological events taking place
Causes - aetiology -
of acute inflammation
micro-organisms - bacteria, fungi, viruses, parasites
pathogenic organisms cause infection
mechanical - trauma - injury to tissue
all injuries even sterile (eg surgery)
Process of acute inflammation
series of microscopic events
localised to affected tissue
take place in the microcirculation
result in the clinical symptoms and signs of acute inflammation - the cardinal signs
What is the microcirculation?
capillary beds, fed by arterioles and drained by venules
extracellular “space” and fluid and molecules within it
lymphatic channels and drainage
Starling forces control flow (fluid flux) across membrane
Q = LpS{(Pc - Pi) - (p - i)}
dynamic balance
hydrostatic and colloid osmotic pressures
compartments and physical constants
Steps - pathogenesis -
in acute inflammation
changes in vessel radius - flow
change in the permeability of the vessel wall - exudation
movement of neutrophils from the vessel to the extravascular space
Effects of exudation
oedema formed
oedema is accumulation of fluid in the extravascular space
explains swelling of tissue in acute inflammation
swelling causes pain - reduce function
Resolution of acute inflammation - ideal outcome
inciting agent isolated & destroyed macrophages move in from blood and phagocytose debris; then leave epithelial surfaces regenerate inflammatory exudate filters away vascular changes return to normal inflammation resolves
Benefits of acute inflammation
rapid response to non-specific insult cardinal signs and loss of function transient protection of inflamed area neutrophils destroy organisms and denature antigen for macrophages plasma proteins localise process resolution and return to normal
Outcomes of acute inflammation
resolution
suppuration
organisation
chronic inflammation
what is inflammation called in the periotoneal cavity
peritonitis
what is inflammation called in the meninges
meningitis
what is inflammation called in the appendix
appendicitis
what is inflammation called in the lungs
pneumonia
what is inflammation called in the pleural cavity
pleurisy
whats the function of neutrophils
mobile phagocytes
- recognise foreign antigen
- move towards it - chemotaxis
- adhere to organism
granules possess oxidants (eg H2O2) and enzymes (eg proteases)
release granule contents
phagocytose & destroy foreign antigen
what happens when neutrophils die
they die when granule contents are released, it produces a soup fluid (pus) and can extend to tissues
whats the role of plasma proteins in inflammation
fibrinogen - coagulation factor - forms fibrin and clots exudate - localises inflammatory process
immunoglobulins in plasma specific for antigen - humoural immune response
what are the Mediators of acute inflammation
molecules on endothelial cell surface membrane
molecules released from cells
molecules in the plasma
molecules inside cells
whats the effects of mediators
vasodilatation increased permeability neutrophil adhesion chemotaxis itch and pain
where do adhesion molecules appear on?
endothelial cells
when are 5- hydroxytryptamine released?
when platelets degranulate in coagulation
why is histamine released
as a result of local injury
does histamine or 5-hydroxytryptamine cause vasodilation
histamine causes vasidilation and 5 hydro causes vasoconstriction
