Pathophysiology of infarction and ischaemia

Question 1

Explain the relationship between atheroma and ischemia.

Answer 1

if atheroma block blood vessels then blood can’t flow so tissues become ischeamic

Question 2

• Describe the consequences of ischaemia.

Answer 2

MI, Transient ischemic attack, cerebral infarction, abdominal aortic aneurysm, cardiac failure

Question 3

• Recognise the supply and demand issues affecting the heart and coronary blood flow and the relevance of these issues to ischaemic heart disease.

Answer 3

If blood/ oxygen supply fail to meet demand due to decreased supply or an increased demand or both

if atheroma in coronary artery it will cause stable angina.
Fissured plaques leads to thrombosis which leads to infarction
atheroma in aorta leads to aneurysm

Question 4

Describe the process of infarction.

Answer 4

Cessation of blood flow and causes necrosis within tissue or organ

Question 5

• Know the reparative process involved in myocardial infarction.

Answer 5

cell death leads to acute inflammation. macrophages phagocytes dead cells and granulation tissue forms, collagen depositions and scar forms

Question 6

Define ischaemia

Answer 6

relative lack of blood supply to tissue/organ leading to inadequate oxygen supply to meet needs of tissue/ organ leading to hypoxia

Question 7

define hypoxia

Answer 7

low inspired oxygen levels or normal inspired oxygen but low partial pressure of oxygen

Question 8

name 4 types of hypoxia

Answer 8

hypoxic, anaemic, stagnant, cytotoxic

Question 9

appearance of infarcts

Answer 9

24 hours- no visual inspection but swollen mitochondria on electron microscopy
24-48- play infarct in solid tissues or red in liver/ lungs
on microscopy acute inflammation initially at the edge of infarct and leads to loss of specialised cells

72 hours- pale goes to yellow and red has little change

end result- scar replaces area of tissue damage, shape depends on territory of occluded vessel