Session 6

Question 1

Define atherosclerosis

Answer 1

Accumulation of the intracellular and extracellular lipid in the intima and media of large and medium sized arteries.

Question 2

What is an alternative definition of atherosclerosis?

Answer 2

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

Question 3

Define arteriosclerosis

Answer 3

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

Question 4

What is the main different between arteriosclerosis and atherosclerosis?

Answer 4

Arteriosclerosis is due to something else, NOT atheroma

Question 5

What are the macroscopic features of atherosclerosis?

Answer 5

Fatty streak, simple plaque and complicated plaque

Question 6

What are fatty streaks?

Answer 6

Lipids deposited in the intima. Yellow and slightly raised.

Question 7

What is simple plaque?

Answer 7

Raised yellow/white. Irregular outline. Widely distributed. Gradually enlarge and coalesce.

Question 8

What is complicated plaque?

Answer 8

This is where something has happened to the atherosclerosis.

Question 9

What causes complicated plaque?

Answer 9

thrombosis, haemorrhage into plaque, calcification or aneurysm formation

Question 10

Why can you get haemorrhage into plaque?

Answer 10

When small new blood vessel forming in the plaque rupture and bleed.

Question 11

What are the common sites of atherosclerosis?

Answer 11

Aorta, coronary arteries, coracoid arteries, cerebral arteries and leg arteries.

Question 12

What is the normal arterial structure?

Answer 12

Endothelium, subendothelial CT, internal elastic lamina, muscular media, external elastic lamina and adventita CT.

Question 13

What is the media in the arteries made up of?

Answer 13

Mainly muscle by there is some elastic tissue as well.

Question 14

What are the early microscopic features of atherosclerosis?

Answer 14

Proliferation of smooth muscle cells, accumulation of foam cells and extracellular lipid.

Question 15

What are the later microscopic features of atherosclerosis?

Answer 15

Fibrosis, necrosis, cholesterol clefts and +/- inflammatory cells. Disruption of internal elastic lamina, media. Ingrowth of blood vessels and plaque fissuring.

Question 16

What are the clinical effects of atherosclerosis?

Answer 16

MI, angina, arrhythmias, cardiac failure

Question 17

What affects can cerebral ischaemia have?

Answer 17

Transient ischaemic attack (mini-stroke), cerebral infarction (stroke) or multi-infarct dementia

Question 18

What effects can mesenteric ischaemia have?

Answer 18

Ischaemic colitis, malabsorption or intestinal infarction

Question 19

What causes peripheral vascular disease?

Answer 19

Atherosclerosis affecting the blood supply of the legs

Question 20

What effects does peripheral vascular disease have?

Answer 20

Intermittent claudication, leriche syndrome (pain in buttocks), ischaemic rest pain and gangrene

Question 21

What are some risk factors of atherosclerosis?

Answer 21

Age, gender, hyperlipidaemia, smoking, hypertension, diabetes, alcohol and infection.

Question 22

How does age affect risk of getting atherosclerosis?

Answer 22

Risk increases with age

Question 23

How does gender affect risk of getting atherosclerosis?

Answer 23

Women relatively protected before menopause due to hormones.

Question 24

How does hyperlipidaemia affect risk of getting atherosclerosis?

Answer 24

High plasma cholesterol associated with atherosclerosis. LDL more significant and HDL is protective.

Question 25

What are chylomicrons?

Answer 25

Transport lipid from intestine to liver

Question 26

What is VLDL?

Answer 26

Carry cholesterol and TG from liver. TG removed leaving LDL.

Question 27

What is LDL?

Answer 27

Rich in cholesterol. Carry cholesterol to non-liver cells.

Question 28

What is HDL?

Answer 28

Carry cholesterol from periphery back to the liver

Question 29

What is apolipoprotein?

Answer 29

Found in the chylomicron. Transport lipid in the blood.

Question 30

What are genetic variations in Apo E associated with?

Answer 30

Changed in LDL levels

Question 31

What is familial hyperlipidaemia?

Answer 31

Genetically determined abnormality of lipoprotein. Leads to early development of atherosclerosis.

Question 32

What are the physical signs of familial hyperlipidaemia?

Answer 32

- Corneal arcus - fat around cornea - Tendon xanthomas - accumulations of macrophages filled with fat - Xanthelasma - fat deposits around eyelids

Question 33

How does cigarette smoking affect risk of getting atherosclerosis?

Answer 33

- Affects the coagulation system - Reduced PGI2 (prostaglandins) - increased platelet aggregation

Question 34

How does hypertension affect risk of getting atherosclerosis?

Answer 34

Causes endothelial damage because of raised pressure.

Question 35

How does diabetes mellitus affect risk of getting atherosclerosis?

Answer 35

Related to hyperlipidaemia and hypertension

Question 36

How does alcohol consumption affect risk of getting atherosclerosis?

Answer 36

Often associated with other risk factors such as smoking and high BP but still an independent risk factor.

Question 37

Give examples of infections that may increase risk of atherosclerosis?

Answer 37

Chlamydia pneumoniae, helicobacter pylori and cytomegalovirus.

Question 38

What was the first theory of atherosclerosis formation?

Answer 38

Thrombogenic theory - plaques formed by repeated thrombi and lipid derived from thrombi

Question 39

What was the second theory of atherosclerosis?

Answer 39

Insulation theory - endothelial injury and inc permeability to lipid from plasma

Question 40

What was the third theory of atherosclerosis?

Answer 40

Reaction to injury - plaque form in response to endothelial injury

Question 41

What was the fourth theory of atherosclerosis?

Answer 41

Monoclonal hypothesis - each plaque is benign tumor because they are due to smooth muscle cells multiplying

Question 42

What does the atherosclerosis process involve?

Answer 42

Thrombosis, lipid accumulation, production of intracellular matrix and interactions between cell types.

Question 43

What cell are involved in atherosclerosis?

Answer 43

Endothelial cells, platelets, smooth muscle cells, macrophages, lymphocytes and neutrophils.

Question 44

What role do endothelial cell splay in atherosclerosis?

Answer 44

Increase permeability to lipoproteins and stimulate proliferation and migration of smooth muscle cells.

Question 45

What role do platelets play in atherosclerosis?

Answer 45

Stimulate proliferation and migration of smooth muscle cells

Question 46

What role do smooth muscle cells play in atherosclerosis?

Answer 46

Take up lDL and other lipid to become foam cells. Also synthesis collagen and proteoglycans.

Question 47

What role do macrophages play in atherosclerosis?

Answer 47

Oxides LDL. Take up lipids to become foam cells. Secrete proteases which modify matrix and stimulate the proliferation and migration of smooth muscle cells.

Question 48

What role do lymphocytes play in atherosclerosis?

Answer 48

TNF and other cytokines may affect lipoprotein metabolism. Stimulate proliferation and migration of smooth muscle cells.

Question 49

What affect do neutrophils have on atherosclerosis?

Answer 49

Secrete proteases leading to continued local damage and inflammation

Question 50

What is endothelial injury due to?

Answer 50

Raised LDL, 'toxins' (smoking), hypertension and haemodynamic stress.

Question 51

What does endothelial injury cause?

Answer 51

Platelet adhesion, PDGF release, SMC proliferation adn migration. Insudation of lipid, LDL oxidation, uptake of lipid SMC and macrophages. Migration of monocytes into intima.

Question 52

How do you prevent atherosclerosis?

Answer 52

No smoking, reduce fat intake, treat hypertension, not too much alcohol, regular exercise.

Question 53

If someone has atherosclerosis, what can you do to help?

Answer 53

Stop smoking, modify diet, treat hypertension, treat diabetes and lipid lowering drugs.