inflammation Flashcards
what is inflammation
a reaction to living tissue around it, not dead tissue
why must tissue be living an vascularised for inflammation
ingredients for inflammation are in circulation
what is fibrinogen
clot protein
very useful in body, interstitial space
turns into fibrin
what does inflammation deliver
concentrated, activated defensive materials in fluid
- phagocytes
- plasma proteins (opsonins, complement)
what is exudate
delivered cells, proteins, fluid
5 cardinal signs of inflammation
swelling - universal sign
warmer
painful
redness
loss of function
signs differ depending on setting but are driven by active changes in microvasculature which delivers the exudate
how does inflammation start
small vessels and ECM respond to danger signals
- damaged matrix
- stressed/dying tissue cells
- mast cells
- pathogens
second stage of inflammation
blood fills capillary and venular bed - redness, warmth
exudate fluid leaves capillaries/venules
interstitial matrix actively hydrates - local swelling
venous outflow becomes sluggish - stasis, congestion
how do cytokines sustain inflammation in substantive injuries
perivascular mast cells degranulate and release cytokines through projections into vessels
incoming leukocytes take over
local swelling
water uptake into connective tissue matrix (hyaluronan)
relaxed compression - collagen detachment and unfolding, fibroblasts relax
hyaluronan in matrix
very hyrophilic
tends to be slightly hydrated as is compressed by surrounding cells so doesnt hold as much water as possible
vascular leak
junction breaks between endothelial cells
capillary filtration pressure
passive leak
from microvessels
usually less important
what happens to leucocytes and platelets entering venules
pushed towards the walls by haemodynamics of normal blood flow
what blocks inflammatory cells from sticking firmly to endothelium
thick glycocalyx ‘blanket’
what causes endothelium to shed glycocalyx
DAMP and cytokines (TNF, IL-1)