pathology of atherosclerosis

Question 1

list some risk factors for atherosclerosis and explain why they are risk factors according to endothelial damage theory

Answer 1

• smoking - free radicals, nicotine, carbon monoxide
• vaping - nicotine
• old age
• hypertension - force
• poorly controlled diabetes - superoxide anions and glycosylation products
• hyperlipidaemia - direct damage

Question 2

define atherosclerosis

Answer 2

• accumulation of fibrolipid plaques in systemic arteries
• limits the blood flow to areas causing ischemia and infarction

Question 3

outline the time course of the progression of atherosclerosis

Answer 3

• birth - no atherosclerosis
• late teenage/early 20s - fatty streaks in aorta, may not
  progress to established atherosclerosis
• 30s/40s/50s - development of established atherosclerotic
  plaques
• 40s-80s - complications of atherosclerotic plaques e.g.
  thrombosis, intraplaque haemorrhage

Question 4

outline the main complictions of atherosclerosis

Answer 4

• embolism
• infarction
• ischemia
• gangrene

Question 5

what is the difference between arteriosclerosis and atherosclerosis?

Answer 5

arteriosclerosis - the hardening of arteries

atherosclerosis - lipid plaques cause arteries to become narrowed and hardened

Question 6

just read this - don’t need to know in detail - how plaques form

Answer 6

• endothelial cells become damaged, leaving gaps in the wall - damaged endothelial cells also lose their preventative functions of clotting and inflammation
• LDLs (cholesterol) get into the wall of the vessel from the lumen
• WBC then enter and oxidise the lipids, turning them into foam cells and causing an inflammatory responce
• this produces calcium salt
• the calcium salt and the LDLs then build up and start to form a plaque, especially as this is a positive feedback loop
• calcification of plaque
• a thrombus then forms on top of the plaque

Question 7

What is the role of endothelial cells in atherosclerosis?

Answer 7

Endothelial cells line the inner layer of blood vessels, maintaining vessel integrity and preventing clot formation. Injury or dysfunction of these cells is the initial event in atherosclerosis

Question 8

How do monocytes and macrophages contribute to atherosclerosis?

Answer 8

Monocytes are recruited from the bloodstream to the artery wall, where they differentiate into macrophages and ingest oxidized LDL, transforming into foam cells within the plaque.

Question 9

What are foam cells, and why are they significant in atherosclerosis?

Answer 9

Foam cells are lipid-laden macrophages that accumulate within plaques and release inflammatory molecules, promoting further plaque growth. They are a hallmark of early atherosclerosis.

Question 10

What role do smooth muscle cells (SMCs) play in atherosclerosis?

Answer 10

SMCs migrate into the intima, proliferate, and produce extracellular matrix (ECM) proteins, which help stabilize the plaque by forming a fibrous cap.

Question 11

What is the function of platelets in atherosclerosis?

Answer 11

Platelets are involved in clot formation when a plaque ruptures. They adhere to the exposed lipid core, initiating a clot that can obstruct blood flow.