What Causes Coronary Heart Disease?
Learn what causes coronary heart disease, how fatty deposits narrow coronary arteries, and how smoking, diet and exercise increase the risk at GCSE.
Coronary heart disease is caused by layers of fatty material building up inside the coronary arteries. This narrows the arteries, reducing blood flow and therefore the supply of oxygen to the heart muscle.
How coronary heart disease develops
The coronary arteries are blood vessels that supply the heart muscle with oxygenated blood. In coronary heart disease:
- Fatty material builds up inside a coronary artery.
- The space inside the artery becomes narrower.
- Less blood can flow to the heart muscle.
- The heart muscle receives less oxygen.
- Less aerobic respiration can take place, so less energy is transferred for contraction.
If the blood supply becomes severely restricted or blocked, part of the heart muscle may be damaged. This can cause a heart attack.
What increases the risk?
A risk factor is something linked to an increased chance of developing a disease. Risk factors for cardiovascular diseases such as coronary heart disease include:
- Smoking, which damages blood vessels and increases the risk of fatty material building up.
- A poor diet, particularly one that contributes to high blood cholesterol levels.
- Lack of exercise, which can contribute to obesity and cardiovascular disease.
- Genetic factors, which can make some people more likely to develop the disease.
Having a risk factor does not guarantee that someone will develop coronary heart disease. It increases the probability.
Exam mistake to avoid
Do not simply write that coronary heart disease is caused by “fat”. State the complete biological chain:
Fatty material builds up in the coronary arteries, narrowing them and reducing the supply of oxygenated blood to the heart muscle.
This answer assumes AQA GCSE Biology, Higher tier, separate science. The key content here is also assessed at Foundation tier and is shared with Combined Science.
