acute inflammation (W11) Flashcards
tissue requirements for inflammation
living, vascularised
inflammation functions
remove cause (if possible)
prevent infection
engage process of repair
what is the name for the fluid, proteins and cells which leave the circulation and go into the interstitial space in inflammation
inflammatory exudate
examples of danger signals that small blood vessels and the extracellular matrix respond to?
damaged matrix
stressed/dying tissue cells
mast cells
pathogens
what do mast cells produce?
histamine
what sustains inflammation in substantive injury
cytokines
what is a major factor in burns? important treatment?
large surface area inflamed therefore lots of exudate being delivered. important to start rapid fluid replacement quickly.
what type of process is exudate leak and tissue swelling? why can this be a problem?
active process, therefore if there is sufficient signalling for inflammation, fluid will continue to be delivered from the circulation and this can occur until your heart fails as circulation no longer supported
when does passive leaking occur -example
sunburn (endothelial cell damage, apoptosis, spaces in blood vessels)
where are white blood cells present when circulating
pushed towards walls due to haemodynamics of normal blood flow
what occurs in the circulation when fluid is lost in exudate
red blood cells clump together into rouleux physically pushing white blood cells to the edge
what stops inflammatory cells from sticking to healthy endothelium
glycocalyx ‘lawn’
what breaks down locally in response to danger signals and why
glycocalyx - allows cells (neutrophils in acute inflammation) to touch endothelium and adhesion molecules
what danger signals cause endothelium to shed glycocalyx
DAMP and cytokines (TNF, IL-1)
platelets role in neutrophils exiting tissue?
bind to and boost endothelial activation
where do white blood cells leave in nearly all tissues
venuoles
where do white blood cells leave in nearly all tissues? exception?
venules
lungs are an exception
what do neutrophils use to travel
matrix - fibrin scaffold
why are swollen tissues that aren’t inflammatory immunocompromised?
gaps between connective tissue and no fibrin scaffold for neutrophils to crawl over
what covers up small damage from neutrophils and why
resident macrophages in tissue will cover up small damage as don’t want area to become inflamed - eg minor skeletal muscle damage after physical exercise
what does the lead neutrophil in inflammation do if the level of danger is high enough?
lead neutrophil will explode and leave a pool of high inflammatory material that activates further neutrophils
what do neutrophils leave behind them after they exit the blood vessels? why?
trail of granule proteins that monocytes can sense and follow
what do monocytes mature to
macrophages
types of exudate?
pus (neutrophil, enzymes, yellow/green)
fibrinous (fibrin>cells, greyish)
serous (fluid>cells)
haemorrhagic (vascular destruction)
what occurs to lymphatics in inflammation
tissue swelling causes vessels to open up, capacity to allow fluid through increases
what additionally passes through lymphatics in inflammation
exudate (so contents can be sampled in lymph nodes)
pain and inflammation?
not all inflammation is painful - eg no pain sensation inside lung (but if pleura is inflamed then pain related to breathing occurs)
