Mechanisms

Atheroma

1. Stress on media intima due to ↑ risk factors

2. Damage to endothelial wall

3. Increased permeability to LDL

4. LDL diffuse through the damaged endothelium and oxidise into lipids

5. Chronic inflammation occurs

6. Monocytes migrate into vessel wall and differentiate into macrophages

7. LDL phagocytosed

8. foam cells form

9. fatty cells accumulate in the intimacy forming lipid core

10. Atheroma develops

11. Atheroma can calcify and can further enlarge

Atherosclerosis (unstable angina)

1. Narrowing of lumen

2. part of plaque ruptures

3. Platelet aggression and thrombus formation

4. Partial occlusion of involved artery

Atherosclerosis (MI)

1. Narrowing of lumen

2. Decrease volume of blood reaching the myocardium

3. Decrease oxygen reaching myocardium

4. Ischemia of the myocardium

5. Cells switch from aerobic to anaerobic metablism

6. increased lactic acid build up

7. increased amount of H+ in ECF

8. Long period of exposure to H+

9. Necrosis of myocardium

Atherosclerosis (Stable angina)

1. Narrowing of lumen

2. Decrease volume of blood reaching the myocardium

3. Decrease oxygen reaching myocardium

4. Ischemia of the myocardium

5. Cells switch from aerobic to anaerobic metablism

6. increased lactic acid build up

7. increased amount of H+ in ECF

8. Irritation of nociceptors in pericardium

9. Impulse carried by C-fibres to T1-T4

10. Information sent to thalamus via spinothalamic tract

11. brin canot differentiate between visceral and somatic pain