Atherosclerosis

Question 1

Define atherosclerosis

Answer 1

-fibrofatty lesions
-soft yellow lipid core
-hardening or thickening of arteries due to a plaque build up on the inner walls of the artery

Question 2

Why is the endothelial layer of arteries so important?

Answer 2

-forms a barrier between the blood and body organs

-stops things sticking/growing on them such as thrombus

-very vasoactive

Question 3

What does EDRF stand for?

Answer 3

endothelial derived relaxant factor

-now known at NO

-substances secreted by the endothelium allowing dilation or constriction

Question 4

What are the 4 key areas of atherosclerosis development?

Answer 4

1- endothelial cell injury
2-great migration of inflammatory cells
3-lipid accumulation and smooth muscle proliferation
4-plaque structure

Question 5

What can cause endothelial damage?

Answer 5

-smoking
-toxic or mechanical stress
-hypertension
-viral infections
-increased circulating levels of low density lipoproteins
(high density goes to the liver, low levels are released from the liver)

Question 6

How can increased levels of circulating low density lipoproteins damage endothelial cells?

Answer 6

-comes in contact with NO it provokes a response which recognises it as a foreign object.

-lipoprotein becomes oxidised- now seen as foreign, provokes the immune system to act and infultrate the endothelial to destroy foreign lipoprotein.

-once T cells, monocytes ect stick to endothelium they become macrophages, then become foamcells- foamcells cant get out of the subendothelium as they are too big

-inflammatory response, cytokins released and begin to form bridges and smooth muscle proliferation occurs

Question 7

What is smooth muscle proliferation?

Answer 7

-grow more smooth muscle than we should

-trying to build a protective core around the site of injury.

Smooth muscle is not the same phenotype as normal- here the smooth muscle is more rigid and doesn’t respond as normal

-there is a formation of a fiborous cap over the injury site

Question 8

Describe the plaque structure

Answer 8

-yellow streak comes from the trapped foamcells in the subendothelium

-lumen size decreases

-smooth muscle proliferation- trys keeping foam cells in the area of injury at the expense of lumen diameter

-occurs over decades
-if plaque ruptures then platelets arrive to try and plug the gap, very sticky- danger is the vessel will occlude, fiborous cap could embolise causeing further damage

Question 9

Where does atherosclerosis occur?

Answer 9

-medium to large arteries such as coronary artery

-more common in bification or torturous vessels- curly, kinked vessels- more prone to atherosclerosis ( for example diabetic patients have torturous vessels from femoral artery to abdomen. )

Question 10

What problems can atherosclerosis cause?

Answer 10

-stroke
-renal artery disease
-aneurysms
-CAD
-peripheral artery disease

why? - narrowing of vessels by fiborous plaque, plaque rupture, intraplaque hemorrage, peripheral emboli, weakening of vessel walls

Question 11

Name some risk factors for atherosclerosis

Answer 11

-age
-gender
-lifestyle
-BMI
-Alcohol
-smoking
-hypertension
-family history
-diabetes, cholestrol levels