(PM3A) Inflammation Flashcards
What is inflammation?
Response to stimuli that can cause body damage
What is the function of inflammation?
Protection from danger/ damage
Promote healing
CAN lead to tissue damage
What are the cardinal signs for inflammation?
(1) Heat – calor
(2) Redness – rubor
(3) Swelling – tumor
(4) Pain –dolor
(5) Loss of function
What is the timescale of an inflammatory response?
(1) Irritant/ vaccine injection/ injury
- Production of inflammatory mediators
- Elimination of pathogen
(2) Resolution
- Removal of inflammatory stimuli
(3) Post-resolution
- Influx of adaptive immune cells
What is the innate immune response?
Largely inflammation
Non-adaptive
How is the innate immune response triggered?
Pattern recognition receptors
What is the adaptive immune response?
Triggered or recruited by innate immune response
Immunological memory
What is the summary of inflammatory events of a physical injury, e.g. a splinter?
(1) Pathogens recognised by macrophages
(2) Stimulates sentinel cells (mast cells)
(3) Signals to blood vessels to recruit other components
- Leukocytes
- Increase blood vessel dilatation
(4) Movement of fluid into affected area from blood vessel
(5) Phagocytosis of pathogen
What is pattern recognition?
The trigger of inflammatory responses
Pattern recognition receptors (PRRs) triggered by pattern-associated molecular patterns (PAMPs)
What are some examples of pattern recognition receptors?
Toll-like receptors
How can different stimuli cause a different inflammatory response?
Different pattern recognition receptors
What are sentinel cells?
Mast cells/ dendritic cells/ macrophages
Release cytokines + inflammatory mediators
Trigger inflammatory responses
What are mast cells?
Reside in most tissues
Activated by IgE + C3a + C5a proteins
Release pro-inflammatory mediators
- e.g. histamine/ prostaglandins/ platelet activating factor
What is the role of endothelial cells in the inflammatory response?
(1) Respond to pro-inflammatory mediators
(2) Release mediators that cause vasodilatation
- e.g. prostaglandins + nitric oxide
(3) Express adhesion molecules for leukocytes
- e.g. selectins
What are some inflammatory-mediating cells that reside in the tissue?
(1) Mast cells
(2) Endothelial cells (of blood vessels)
(3) Macrophages
(4) Leukocytes
(5) Platelets
What are the vascular events of the inflammatory response?
Account for rubor/ tumor/ calor
Triggered by cytokines + mediators
Causes:
(1) Vasodilatation
(2) Vascular permeability to fluid
(3) Expression of adhesion molecules on endothelial cells
What are proteolytic cascades?
Convert factor XIIa from plasma into pro-inflammatory products
These products activate the complement cascade
ø C1-C9
What are leukocytes?
Form the pus
Roll + extrude endothelial cell layer to enter inflammation site
Attracted to pathogens by chemotaxis
Engulf + kill + digest pathogens
What is leukocyte extrusion?
(1) Rolling of leukocytes down endothelial cells of blood vessel (veins ONLY) by inflammatory site
(2) Binding to selectins on endothelial membrane
(3) Extrusion of leukocytes through endothelial cells into tissue
What are some later cellular events in inflammation?
Caused by monocytes + macrophages
Secondary arrival hours after neutrophils
What is chemotaxis?
Movement of leukocytes to site of pathogen
Following chemical signals
Process in inflammatory response
How does failure of healing affect inflammation?
Causes chronic inflammation
Leads to loss of function
Can be:
(1) Hypersensitivity – e.g. asthma
(2) Infectious disease – e.g. tuberculosis
(3) Auto-immune diseases
What are some molecular hallmarks of non-resolving inflammation?
(1) TNF increasing
(2) IFNs increasing
(3) IL-6 increasing
What are some examples of acute inflammatory responses?
(1) Hayfever
(2) Contact dermatitis
(3) Acute asthma attack
(4) Uritcaria
What are some examples of chronic inflammatory responses?
(1) Asthma
(2) Rheumatoid arthritis
(3) Atherosclerosis
What is the role of chemokines and cytokines?
Mediation of inflammatory signals
What are cytokines?
Protein/ peptide signalling molecules
Modulate function of other cells in inflammation + immunity
C3a/ TNF-alpha/ IL-1 are some major pro-inflammatory cytokines
What are chemokines?
Type of cytokine
Control leukocyte migration
e.g. C3a/ C5a/ LTB4
What happens following intradermal injection of inflammation?
(1) Flush - arterial vasodilatation
(2) Oedema/ swelling (wheal)
(3) Flare –sensory nerve induced dilatation
What occurs following stimulation of H1 receptors by histamine?
(1) GIT constriction
(2) Bronchial smooth muscle constriction
(3) Dilatation of blood vessels – stimulates endothelial cells
(4) Itch – associated with wound healing
How is histamine released?
Mast cell degranulation
Caused by C3a, C5a + IgE
What are eicosanoids?
Lipid-derived mediators
What is the major component for forming lipid-derived inflammatory mediators?
Arachidonic acid
What are prostanoids?
Type of eicosanoids
Formed by the action of cyclooxygenases (COXs)
Most are termed ‘prostaglandins’