Inflammation

Question 1

what are the main roles of acute inflammation

Answer 1

• destroy the invading pathogen
• induce local blood clotting to reduce the spread of infection through the bloodstream
• repair injured tissue

Question 2

what are the main components of acute inflammation

Answer 2

vascular
cellular

Question 3

what do pattern recognition receptors detect

Answer 3

PAMPs
DAMPs

Question 4

what are PAMPs

Answer 4

pathogen associated molecular patterns
exogenous molecules

Question 5

what are DAMPs

Answer 5

damage associated molecular patterns
endogenous molecules

Question 6

what do activated macrophages do when there is an infection

Answer 6

they release lipid mediators to vasodilate and increase the volume of blood, as well as slowing blood flow

Question 7

what are the lipid mediators produced from macrophages that act to vasodilate

Answer 7

leukotrienes
prostaglandins
nitric oxide
platelet activating factor

Question 8

why is slowed blood flow from vasodilation useful when there is infection or damage

Answer 8

slows the spread of the pathogen through the circulation and gives more time for other cells to enter the tissue

Question 9

function of nitric oxide produced from macrophages in response to infection or damage

Answer 9

promotes permeability of blood vessels to allow fluid leakage to cause swelling
this allows local influx of fluid and plasma proteins like complement and antibodies to help concentrate the proteins in the infected tissue

Question 10

function of complement

Answer 10

clear infectious microbes

Question 11

function of kinin system

Answer 11

protease cascade involving proteins cleaving and activating other proteins
production of bradykinin

Question 12

function of bradykinin

Answer 12

increase vascular permeability and pain sensation by sensitisation of sensory nerve endings

Question 13

what is the function of the coagulation system

Answer 13

produce fibrin clot
clot stops bleeding and prevents spread of the pathogen in the stream
some pathogens are trapped inside clots

Question 14

how do endothelial cells behave during inflammation

Answer 14

they increase expression of P and E selectin, which allows the vascular component to interact with the cellular component to allow entry into tissues.

Question 15

what is P selectin released in response to

Answer 15

TNF alpha
leukotriene B4
histamine
C5a

Question 16

what do the selectins expressed from activated endothelial cells allow to happen

Answer 16

they bind to glycoproteins on the surface of immune cells like neutrophils and monocytes
they will roll along the vessel wall until they completely stick
CXCL8 increases during inflammation to strengthen this interaction
after sticking the immune cells can enter the tissue and follow chemotactic gradients to the infected site

Question 17

how is resolution of infection brought about

Answer 17

regulatory molecules come in and control the inflammatory response

Question 18

how is the inflammatory response paused

Answer 18

it is not self limiting and must be regulated by mediators and mechanisms to decrease the response

Question 19

provide examples of how the inflammatory response is decreased

Answer 19

• neutrophils have a short half life and will undergo apoptosis after a few days, and are then removed through efferocytosis with macrophages
• macrophages are reprogrammed through the efferocytosis to make them proresolving and begin to remove dead cells, and release cytokines to promote healing
• resolution mediator release to stimulate efferocytosis, and decrease of neutrophil chemotaxis, adhesion molecule expression and permeability.
• angiogenesis occurs
• epithelial cells proliferate
• collagen deposited to return the cell to normal function