Atherosclerosis

Question 1

What is a atheroma

Answer 1

An accumulation of intracellular and extracellular lipid in the intima and media of large and medium sized arteries

Question 2

Atherosclerosis

Answer 2

The thickening of hardening of arterial wall as a consequence of atheroma

Question 3

Arteriosclerosis

Answer 3

The thickening of the walls of arteries
and arterioles usually as a result of
hypertension or diabetes mellitus

Question 4

Macroscopic features of a atherosclerosis

Answer 4

Fatty streak

• lipid deposits in intima
• yellow, slightly raised

Simple plaque

• raised yellow/white
• irregular outline
• enlarge and coalesce

Complicated plaque

• thrombosis
• haemorrhage
• calcification
• aneurysm

Question 5

Common sites of Atherosclerosis

Answer 5

 Aorta - especially abdominal

 Coronary arteries

 Carotid arteries

 Cerebral arteries

 Leg arteries

Question 6

Microscopic features of atherosclerosis- early changes

Answer 6

Proliferation of smooth muscle cells

Accumulation of foam Cells

Extracellular lipids

Question 7

Microscopic features of atherosclerosis- later changes

Answer 7

Fibrosis
Necrosis
Cholesterol clefts
Maybe increase in inflammatory cells

Disruption of internal elastic lamina
Damage extends into media
Ingrown of blood vessels
Plaque fissuring

Question 8

Chylomicrons

Answer 8

Transport lipid from intake to liver

Question 9

LDL

Answer 9

Rich in cholesterol

Carry cholesterol to non-liver cells

Question 10

VLDL

Answer 10

Carry cholesterol and TG from over

TG removed leaving LDL

Question 11

HDL

Answer 11

Carry cholesterol from periphery back to liver

Question 12

Physical signs of familial hyperlipidaemia

Answer 12

Genetically determined abnormalities of lipoproteins

corneal arcus
Tendon xanthomas
Xanthelasma

Question 13

Thrombogenic theory for atherosclerosis

Answer 13

Plaques formed by repeated thrombi

Lipid derived from thrombi

Overlying fibrous cap

Question 14

Insudation theory for atherosclerosis

Answer 14

Endothelial injury
Inflammation
Increased permeability to lipid from plasma

Question 15

Reaction to injury hypothesis for atherosclerosis- 1972 Ross and glomset

Answer 15

Plaques form in response to endothelial injury
Hypercholesterolaemia leads to endothelial damage
Injury increases permeability and allows platelet adhesion
Smooth muscle cells proliferate and migrate

Question 16

Reaction to injury hypothesis for atherosclerosis- 1986 Ross

Answer 16

 endothelial injury may be very subtle and be
undetectable visually
 LDL, especially oxidised, may damage
endothelium

Question 17

The monoclonal hypothesis- atherosclerosis

Answer 17

 crucial role for smooth muscle proliferation
 each plaque is monoclonal
 might represent abnormal growth control
 is each plaque a benign tumour?
 could atherosclerosis have a viral aetiology?

Question 18

What is involved in atherosclerosis

Answer 18

Thrombosis
Lipid accumulation
Production of intercellular matrix
Interactions between cell types

Question 19

How are endothelial cells involved atherosclerosis

Answer 19

Haemostasis

Altered permeability to lipoproteins

Production of collagen

Stimulation of proliferation and migration of smooth muscle cells

Question 20

How are platelets involved in atherosclerosis

Answer 20

Haemostasis

Proliferation and migration of smooth muscle cells

Question 21

How are smooth muscle cells involved in atherosclerosis

Answer 21

Take up LDL and other lipid to become foam cells

Synthesise collagen and proteoglycans

Question 22

How are macrophages involved in atherosclerosis

Answer 22

Oxidise LDL
Take up lipid and become foam cells
Secrete pro teases which modify matrix
Stimulate proliferation and migration of smooth muscle cells

Question 23

How are lymphocytes involved in atherosclerosis

Answer 23

TNF may affect lipoprotein metabolism

Stimulate proliferation and migration of smooth muscle cells

Question 24

How are neutrophils involved in atherosclerosis

Answer 24

Secrete protease leading to continued local damage and inflammation