6 Inflammation Flashcards
inflammation
local response to injury or invasion by pathogenic organisms
what may inflammation be involved in
allergic reactions
what may inflammation be a prequel to
prequel to the body-wide immune response
inflammation characteristics
rubor
calor
dolor
tumor
rubor
red
calor
hot
dolor
painful
tumor
swollen
what does rubor and calor do
> Result of local vasodilation
> Increases blood flow to the affected area
what does dolor do
> Result of stimulation of nociceptive terminals by chemicals released from damaged tissue
Leads to awareness and avoidance/protection
what does tumor do
> Result of increased capillary permeability
Proteins move from blood into interstitial fluid: osmotic effect attracts water
White blood cells move into damaged tissue
Provides some physical protection
what should inflammation results be
> repair of damaged tissue
> defeat of pathogens
what are the inflammation results often
> Ineffective (infection occurs)
Extended beyond duration of cause
Inappropriate (allergy)
Chronic (e.g. arthritis)
what can help inflammation
- Relieve symptoms
- Reduce pain
what is the triple response
red reaction
flare
wheal
Red reaction effect
- initial reddening (hyperaemia)
- due to local arteriolar vasodilation
what is red reaction initiated by
> mechanical effects of injury
> histamine
flare effect
- Spreading of red area
- Due to axon reflex, via spinal cord and local branching
what is the flare response initiated by
mechanical stimulation of nociceptive C-fibres
what does flare response lead to
powerful vasodilators in skin (Substance P, CGRP)
wheal effect
Formation of raised area
Formation of exudate associated with vascular and cellular events – a very complex process…
what causes wheal
Due to accumulation of fluid (exudate) in the tissue, after increase in capillary permeability (inter-endothelial junctions)
where does exudate form
site of injury
> vascular events (factors from plasma)
> cellular events (factors from cells)
characteristics of exudate
- High specific gravity (1.02)
- High protein levels
- Cells & cell fragments
Vascular events
- Blood leaks into tissues and initiates enzyme cascades
what initiates vascular events
Initiated by the increased blood flow of the red reaction
what do vascular events cause
local haemoconcentration
what do vascular events assist
haemostasis
why does the capillary wall become leaky
- endothelial contraction
- loss of junctions
- direct injury
- local hormones
effect of leaky capillary
Plasma leaks out and is exposed to collagen, von-Willebrand factor, non-endothelial cells = enzyme cascade
kinin cascade
kallikrein
bradykinin = vasodilation and pain
eicosanoids = vasodilation and pain
fibrinolytic cascade
plasmin = fibrinolysis
aids complement cascade to form C9 which causes bacterial cell lysis
coagulation cascade
thrombin aids complement cascade
haemostasis
what does fibrinolysis aid
haemostasis to wound repair in coagulation cascade
eicosanoids
slow acting, delayed response
what does kininogen form
B1 and B2 receptors
kininogen (alpha-globulin) effects
contraction of visceral smooth muscle
relaxation of vascular smooth muscle
increase capillary permeability
stimulate pain receptors
endothelial cells effects
vasodilation
bronchospasm
pain
many other actions
Cellular events: tissue cells
Endothelial cells
Represent the site of tissue damage. Penetration of endothelium allows blood proteins to contact tissues
what do endothelial cells generate
prostaglandins
where is endothelial cells active
wound repair and angiogenesis
Cellular events: tissue cells Tissue macrophages (Histiocytes)
Consume invading bacteria, particulates, damaged tissue etc.
where are tissue macrophages (Histiocytes) active
immune response (antigen presentation) and wound repair
Cellular events: tissue cells - what do fibroblasts synthesise
extracellular matrix proteins (collagen, fibronectin, laminin etc.) and ECM-regulating enzymes during wound repair and tissue turnover
what does histamine cause
vasodilation arteriolar permeability smooth muscle contraction pain and itch allergic responses
what does IL-1 do
stimulates fibroblasts (wound repair)
what does IL-2 do
promotes T-cell proliferation (immune response)
what do polynuclear leukocytes
adhere to and migrate through endothelium (chemotactic response to complement cascade)
Drug treatments for inflammation
Steroidal: Glucocorticoids
Non-steroidal (NSAIDs)
Anti-histamines
