3. Heart Disease

Question 1

Atheroma Formation

Answer 1

The endothelium layer is usually smooth and unbroken.

If damage occurs to the endothelium (eg because of high blood pressure), white blood cells and lipids from the blood clump together under the lining to form fatty streaks.

These streaks get bigger and form a fibrous plaque called an atheroma.

Question 2

Exam tip

Atheromas

Answer 2

Atheromas form within the wall of an artery – they do not form on the wall. Don’t write that they form in veins, capillaries or blood vessels.

Question 3

Can you think what problems an atheroma might cause?

Answer 3

They partially block the lumen of the artery and restrict the blood flow, which causes blood pressure to increase

Question 4

Aneurysm

Answer 4

Atheroma plaques damage and weaken arteries.

These weakened points swell to form a balloon like blood filled structure called an aneurysm.

These often burst, leading to haemorrhage.

Question 5

Thrombosis

Answer 5

An atheroma plaque can break through the endothelium (inner lining of the artery)
This damages the artery wall and leaves a rough surface
Platelets accumulate at the site of the damage and form a blood clot (thrombus)
This blood clot can form a complete blockage of the artery, reducing blood supply to tissues beyond it
Or, it can become dislodged, move and block another artery.

Question 6

What is atheroma and how may it cause myocardial infarction?

Answer 6

1. Cholesterol/plaque/lipoprotein/LDL/fatty material/cells;
2. In artery wall/under lining/endothelium of artery/blood vessel;
3. Atheroma linked to blood clot/thrombosis
4. (Blocks) coronary artery/artery supplying heart muscle/ tissue/cells.
5. Reduces oxygen/glucose supply (to heart muscle/tissues/cells);

6 (Heart muscle/tissue/cells) unable to respire/dies:

Question 7

Why might a doctor prescribe clot busting drugs as well as advice on diet and exercise to someone who has had a heart attack?

Answer 7

Giving up smoking, eating less fat and doing more exercise take time to have an effect. Whilst they are still at risk, patients may be given drugs to ‘thin’ the blood so that it is less likely that a clot will form and break away from the blood vessel wall to cause an arterial blockage in the heart or brain.