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Flashcards in Acute Inflammation Deck (73)
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Define acute inflammation

A fundamental response to maintain the integrity of organism

A series of protective changes occurring in living tissue as a response to injury


What are the cardinal signs of inflammation

Rubor - redness
Calor - heat
Tumor - swelling
Dolor - pain
Loss of function


What are the causes of acute inflammation

Microorgansims -including bacteria, fungi, viruses, parasites
Mechanical trauma - injury to tissues even in surgery
Chemical - unstable environment e.g. upset pH or bile and urine causing irritation when in inappropriate places
Physical - extreme conditions e.g. heat, cold, ionising radiation
Dead tissue - cell necrosis irritates adjacent tissue
Hypersensitivity - causes several classes of reaction


What changes occur in acute inflammation

Changes in:
Vessel radius (flow)
The permeability of the vessel wall (exudation)
And movement of neutrophils from the vessel to the extravascular space


What are the benefits of acute inflammation

A rapid response to non-specific insult
Cardinal signs and loss of function (allowing transient protection of the inflamed area)
The neutrophils destroy organisms and denature antigens for macrophages
Plasma proteins localise the process
It can be resolved and return to normal


What is acute inflammation

Series of microscopic events occur which are localised to the affected tissue
They take place in the microcirculation
Result in the clinical symptoms and signs of acute inflammation


What happens in the process of exudation

There is a net movement of plasma from capillaries to extravascular space causing fluid to be leaked which is exudate

Exudate fluid is rich in protein and plasma and it includes Ig and fibrinogen


What can exudation cause

Oedema - the accumulation of fluid in the extravascular space

Presents as the swelling of tissue in acute inflammation which cause pain and reduce function


How are inflammation at various anatomical positions named

e.g. peritoneal cavity inflammation is peritonitis, meninges inflammation is meningitis, appendix inflammation is appendicitis.


What is an exemption to the rule of how inflammation is named

Lungs which is known as pneumonia
Pleural cavity is known as pleurisy


What is the role of neutrophils

They are mobile phagocytes
Recognise foreign antigen
Adhere to organism
Release granule contents
Phagocytose and destroy foreign antigen


What do the granules in neutrophils contain

Oxidants (e.g. H202)


What happens to the neutrophil when the granule contents are released

They die


What is produced from a neutrophil

A 'soup' of fluid
Bits of cell
Endogenous proteins

This is known as pus


What is fibrinogen

A coagulation factor which forms fibrin and colts exutade
It localises inflammatroy processes


What is the role of immunoglobulins in plasma

They are specific for the antigen
Involved in the humoural immune response


Name the type of mediators in acute inflammation

Molecules on endothelial cell surface membrane,
Molecules released from cells
Molecules in the plasma


What are the collective effects of mediators

Increased permeability
Neutrophil adhesion
Itch and pain


What are cell surface mediatiors

Adhesion molecules which appear on endothelial cells


Give example of cell surface mediatiors

ICAM-1 which help neutrophils stick
P-selectin which interact with the neutrophil surface


Give examples of the molecules released from cells

5-hydroxytryptamine (serotonin)
Prostgladins (arachidonic acid metabolites via cyclo-oxygenase pathway)
Leukotrienes (arachidonic acid metabolites via lipoxygenase pathway
Omega-3 polyunsaturated fatty acids
Platelet-activating factor (PAF)
Cytokines and chemokines (e.g. TNFα, IL-1)
Nitric oxide (NO)
Oxygen free radicals (H2O2, OH-, O2-)


Describe histamine

Preformed in mast cells beside vessels, platelets and basophils
Released due to local injury which cause IgE mediated reactions
Cause vasodilatation
Increase permeability
Act via H1 receptors on endothelial cells


Describe 5-hydroxytryptamine (serotine)

Preformed in platelets
Released when platelets degranulate in coagulation causing vasoconstriction


Describe prostglandins (arachidonic acid metabolites via cyclo-oxygenase pathway)

Formed from many cells including endothelium and leukocytes
Many of the cells promote histamine effects and inhibit inflammatory cells


Give an example of a prostglandins and its actions

Thromboxane A2
Promotes platelet aggregation and vasoconstriction

Opposite to PGD2 and PGE2
PGE determines the effectiveness of non-steroidal anti-inflammatory drugs.


Give examples of leukotrines

They are vasoactive so have a dynamic effect on vessels to increase permeability as well as constrict smooth muscle


What are prostglandins

Arachidonic acid metabolites from the cyclo-oxygenase pathway


What are leukotrines

Arachidonic acid metabolites from the lipoxygenase pathway


What do omega-3 polyunsaturated fatty acids do

Decrease the synthesis of arachidonic acid that is derived from inflammatory mediators


Where are platelet-activating factors (PAF) present

Cell membrane of activated inflammatory cells