Atheroma

Question 1

Definition

Answer 1

The hardening of medium/large vessels due to plaque formation

Question 2

Differentiation between atherosclerosis and arteriosclerosis

Answer 2

Arteriosclerosis: refers to general hardening of vessel walls
Atherosclerosis: refers to hardening due to plaque formation

Question 3

Causes

Answer 3

Hypercholesteremia: Can be genetic as well as due to build up over time.
In genetic case due to lack of LDL receptors on cell membranes which leads to the build up of cholesterol in the blood
Hyperlipidemia: LDL, HDLs, triglycerides

Question 4

Risk factors

Answer 4

High:
-male
-smoker 
-hypertension 
-diabetes 
Lower:
-obesity 
-sedentary lifestyle 
-low birth weight

Question 5

Development

Answer 5

1- response to injury to endothelium lining
2-chronic inflammation response to damage
3-Advanced

damage to endothelium leads to LDLs moving under endothelium

• monocytes move into endothelium and breakdown the LDLs
• macrophages die due to apoptosis but release cytokines
• This leads to platelet aggregation
• platelets release a tissue factor which causes smooth muscle proliferation ( ICAM-1, E-selectin)
• smooth muscle proliferates from tunica media into tunica intima and releases elastic fibres and collagen to form a fibrous cap
• calcium released which adds to solidification
• if rip in fibrous cap= blood clotting which further occludes vessel
• if advanced then micro-thrombi can form on exposed plaque surfaces

Question 6

How does it resolve

Answer 6

1- progressive occlusion :
-up to 50-70% can lead to reversible ischaemia
-in very severe stenosis leads to ischaemia at rest
e.g. in coronary artery: MI and angina
in carotid: stroke
2-acute occlusion:
-rupturing of plaque into blood stream
-causes coagulation cascade
-total occlusion= irreversible ischaemia
3- embolisation: plaque becomes dislodged
4-aneurysm:
-weakening in the lining under the plaque
-gradual dilation of the vessel
-sudden rupture= haemmorage
5-hypertension:
-clot occludes renal artery
-activates renin-angiotensin-aldosterone system
-triggers hypertension

Question 7

Atheroma prone to rupturing?

Answer 7

• Large lipid core
• thin fibrous cap
• prominent inflammation

Question 8

How to prevent

Answer 8

• stop smoking
• reduce salt and sugary intake
• exercise
• cholesterol preventing drugs e.g. aspirin

Question 9

blood flow and radius size correlation

Answer 9

Q=P/R 
Q : blood flow 
R: resistance 
R is inversely proportional to radius 
If R decreases then Q will decrease

Question 10

signa for hyperlipidemia

Answer 10

• corneus archus
• tendon xantholomata
• LDLs, HDLs, triglycerides