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AQA GCSE Biology · 8461
AQA 8461 · 4.2.2.4 Coronary Heart Disease Check the specification (PDF) (opens in a new tab)
Explain the pathology of coronary heart disease and its effect on blood flow.
Evaluate the advantages and disadvantages of treating cardiovascular diseases with drugs, mechanical devices, or transplants.
Describe the use of stents and statins.
Explain the consequences and treatments for faulty heart valves.
Discuss heart transplants and the use of artificial hearts.
The heart pumps blood to the lungs and around the body, but its muscle cells also need a supply of oxygen and glucose. They receive these through the coronary arteries, blood vessels that run over the heart. Oxygen enables the muscle cells to release energy by respiration so that the heart can keep contracting.
In coronary heart disease (CHD), layers of fatty material build up inside the coronary arteries. The space available for blood to pass through becomes narrower, so less blood flows to the heart muscle. Its cells then receive less oxygen. If the blood supply becomes severely restricted or blocked, heart muscle can be damaged in a heart attack. CHD is non-communicable: it cannot be passed from one person to another.
Fatty material narrows a coronary artery and restricts blood flow. A stent holds the narrowed artery open so more blood can reach the heart muscle.
A stent is a small tube inserted into a narrowed coronary artery. It holds the artery open, improving blood flow so that more oxygen can reach the heart muscle. This lowers the risk of a heart attack. A stent acts directly on the narrowed artery; it does not lower the cholesterol level in the blood. Insertion also carries risks, including infection or a blood clot forming at the stent.
Statins are drugs that lower blood cholesterol. High blood cholesterol is linked to fatty deposits in arteries, so lowering it slows the rate at which fatty material is deposited. This reduces the risk of coronary heart disease. Unlike a stent, a statin does not immediately hold a narrowed artery open: it is generally taken regularly over a long period. Statins can cause unwanted side effects in some people. These different actions explain why the benefits and risks of the two treatments need to be considered separately.
Fatty material builds up inside coronary arteries → arteries narrow → blood flow falls → heart muscle receives less oxygen. Severe restriction or blockage can cause a heart attack. CHD is non-communicable.
Trace the full chain: fatty material builds up → coronary artery narrows → less blood flows → heart muscle receives less oxygen.
Do not say that stents lower blood cholesterol. Stents hold an artery open; statins lower blood cholesterol.
When comparing treatments, link each benefit or risk to the treatment rather than listing unrelated facts.
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Coronary heart disease
A disease in which fatty material builds up inside the coronary arteries, narrowing them and reducing blood flow to the heart muscle.
Coronary arteries
Blood vessels that supply the heart muscle itself with oxygenated blood.
Stent
A small tube inserted into an artery to hold it open and allow blood to flow through.
Statin
A type of drug used to lower blood cholesterol, slowing the build-up of fatty material in arteries.
Put your knowledge into practice — try past paper questions for Biology
Coronary heart disease
A disease in which fatty material builds up inside the coronary arteries, narrowing them and reducing blood flow to the heart muscle.
Coronary arteries
Blood vessels that supply the heart muscle itself with oxygenated blood.
Stent
A small tube inserted into an artery to hold it open and allow blood to flow through.
Statin
A type of drug used to lower blood cholesterol, slowing the build-up of fatty material in arteries.