Acute Inflammation

Question 1

What is the definition of inflammation?

Answer 1

Protective response of vascularised tissue to injury
eradicate cause + consequence of injury
linked to repair + healing

Question 2

Key features of acute inflammation

Answer 2

blood components, chemical mediators, blood vessels, endothelium, cellular and extracellular connective tissue

Question 3

describe the features of acute inflammation that distinguish it from chronic inflammation

Answer 3

early response, lasts from minutes-days
involves mostly neutrophils but also macrophages, vasodilators, exudate, fibrin
is non specific

Question 4

describe the features of chronic inflammation that distinguish it from acute inflammation

Answer 4

later response, lasting weeks - years
macrophages, lymphocytes, plasma cells, fibrosis
specific or nonspecific

Question 5

what are the causes of acute inflammation?

Answer 5

infection, trauma, burns, infarction

Question 6

what are the aims of acute inflammation

Answer 6

deliver nutrients and defence cells
destroy infective agents
remove debris

Question 7

Describe the clinical signs of acute inflammation

Answer 7

redness (vasodilation + hyperaemia) 
heat
pain (nerve endings + chemicals)
swelling (exudate + hyperaemia)
loss function bc of trauma + combined effects of above

Question 8

what are the sources of chemical mediators

Answer 8

cell derived or plasma derived circulating around and activated at inflammatory site

Question 9

histamine source + effects

Answer 9

mast + basophils

vasodilation

Question 10

prostaglandins source + effect

Answer 10

mast + leuk

pain + fever

Question 11

leukotrienes source + effect

Answer 11

mast + leuk

increase vessel permeability, chemotaxis + leukocyte activation

Question 12

PAF sources + effects

Answer 12

platelet activation factor = mast + leuks

increases vasodilation + permeability, chemotaxis, degranulation

Question 13

ROS sources = effect

Answer 13

reactive oxygen species = leuk

kill microbes + tissue damage

Question 14

NO sources + effects

Answer 14

endothelium + macrophages

vascular smooth muscle relaxation + kill microbes

Question 15

cytokines sources + effects

Answer 15

1L-1, TNF etc
macrophages + endo + mast
endo activation, fever, pain, anorexia, hypotension, shock

Question 16

systemic effects of acute inflammation

Answer 16

malaise, myalgia, arthralgia, decreased appetite

Question 17

steps to fever

Answer 17

exogenous toxins stim prod of endogenous pyrogens (cytokines)
these stim prostaglandin synthesis within vascular and perivascular cells of hypothalamus
prostaglandins stim neurotransmitters to increase body temp

Question 18

What is the vascular response to a.inflam?

Answer 18

initial increased dilation + blood flow, which then slows

vessels become permeable to h2O, proteins, cells from plasma towards damaged area (exudation)

Question 19

What is exudate?

Answer 19

fluid with proteins + cells

escapes blood vessels and goes towards the injured site

Question 20

Functions of exudate

Answer 20

mediate local defences
destroy active agent
break down + remove damaged tissue

Question 21

Components of exudate

Answer 21

Fibrin = prevents migration of microorganisms to assist passage of wbcs
fluid = nutrients, mediators, immunoglobuins, circulates vessels
neutrophils = ingest/kills offenders
macrophages = phagocytose bacteria (more so in chronic)
lymphocytes (more so chronic)

Question 22

Types of exudate

Answer 22

purulent/suppurative = pus (neutrophils, necrotic cells + oedema), has abscesses caused by pyrogenic bacteria, localised tissue necrosis and can be walled by fibrosis (in chronic)
fibrinous -> increased fibrin, common in membrane lined cavities
serous -> absence of prominant cellular response = outpouring thin fluid (low plasma proteins + cells) and happens with blisters + burns
haemorrhagic = increased rbcs from damaged and ruptures bvs

Question 23

general cellular response

Answer 23

circulating neutrophils are attracted to damage
margination = neuts adhere to swollen endothelial cells
migration = macrophages + lymphocytes migrate

Question 24

describe neutrophilia

Answer 24

increased neut count in blood
cytokines IL1 + TNF
released from masts + neuts
cytokines stim increase in neut release + production in bone marrow

Question 25

what are neutrophils and how long do they live

Answer 25

polymorphonuclear leukocytes => varied lobe numbers | cirulate blood for under 16hrs and live 1-2 days

Question 26

what are neutrophils equipped with

Answer 26

lysosomes (enzymes, complement, but also release free radicals) glycogen - anaerobic respiration pseudopodia - amoeboid movement from vessels to tissues microtubules - intracellular movement

Question 27

What is the response of neutrophils to tissue injury

Answer 27

- endothelial cells release chemokines => inc expression integrin adhesion molecules on neuts - neuts bind to endo cells - mast cells release hisatmine => open intercellular junctions between endothelial cells

Question 28

what is diapedesis

Answer 28

- neuts extend pseudopdia through gaps in capillary walls | amoeboid movement driven by chemoattractant molecules from damaged tissue

Question 29

Describe neutrophil phagocytosis

Answer 29

at the site of abnormality, neuts unleash destructive mechanisms - can die in process - becomes part of exudate

Question 30

Describe monocytes and macrophages

Answer 30

in blood they're monocytes, in tissues they're macrophages eg osteoclasts, dust cells, microglia monos leave circulation @ injured site, phagocytose tissue debris + pathogens, and initiate immune response macrophages live + last longer

Question 31

describe the 3 outcomes of acute inflammation

Answer 31

depending on the tissue type, extent of damage + type/duration of injury resolution => normalcy, replaced cells, phagocytes cleared debris, exudate removed via lymphatics -variable regeneration eg myocardial inflammation chronic inflammation