Lecture 19 - Ischemic Infarction

Question 1

Causes of ischemia?

Answer 1

external or internal occlusion, spasm, capillary blockage, shock, increased demand, venous obstruction

Question 2

Tissues of increasing sensitivity to ischemia?

Answer 2

fibroblasts/macrophages, skeletal muscle, myocardium, renal epithelium, neurons

Question 3

factors influencing effects of occlusion?

Answer 3

organ blood supply anatomy, vessel size, speed of onset, duration of occlusion, reperfusion, metabolic demands of tissue, adequacy of circulatory system

Question 4

Infarction definition?

Answer 4

necrosis of tissue due to ischemia

Question 5

Infarct types?

Answer 5

red in tissue with dual supply, white in tissue with single supply

Question 6

Typical infarction - 24hr?

Answer 6

acute inflammation (neutrophils) develop from viable margins

Question 7

Infarction - 1-3 days?

Answer 7

macrophages and lymphocytes appear, fibroblasts and endothelial cells appear to form granulation

Question 8

Infarction - 6-8 weeks?

Answer 8

infarct organised into fibrous scar (liver could attempt regeneration)

Question 9

Mi treatment?

Answer 9

thrombolitic agents, mechanical re-expansion/coronary artery bypass - risk of reperfusion injury

Question 10

Reperfusion injury?

Answer 10

after long periods of ischemic injury, blood flow can cause ROS production, leading to oxidative stress