AQA GCSE Coronary Heart Disease (CHD) (Biology)
Coronary Heart Disease (CHD)
The coronary arteries supply the heart muscle with oxygenated blood and glucose. The heart muscle cells use the glucose and oxygen for aerobic respiration, to release energy.
In coronary heart disease layers of fatty material build up inside the coronary arteries, narrowing them. This process occurs over many years and will reduce the flow of oxygenated blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle.
If the coronary artery is partly blocked there will be reduced blood flow to the heart muscle. The heart muscle cells will need to partly respire by anaerobic respiration, producing lactic acid. Lactic acid is a mild poison causing muscle fatigue and angina pain.
If the coronary artery is completely blocked the heart muscle cells will not be able to carry out aerobic respiration to release energy and die, this is when a heart attack occurs.
The image below shows a blockage in the coronary arteries and the parts of the heart muscle that will not receive oxygenated blood.
Treatment of coronary heart disease
There are three ways that doctors treat coronary heart disease
1.Use of statin medication
2.Use of stents within blood vessels
3.Bypass surgery
Statin medication
Statins are a type of drug which is prescribed by a doctor to lower blood cholesterol levels. This medication will slow down the rate at which the fatty deposits form in the arteries.
Use of Stents
Stage 1.
The stent is inserted into a blood vessel.
Stage 2.
A balloon is inflated to open up the cage of the stent.
Stage 3.
The balloon is deflated and withdrawn. The cage of the stent will stay open, which widens the blood vessel, increasing blood flow.
Bypass Surgery
Blood is diverted around the blockage, using a vein taken from another part of the body.
This will increase oxygenated blood flow to the heart muscle.
| Coronary heart disease treatment | Advantage | Disadvantage |
|---|---|---|
| Statins | Reduces the blood cholesterol levels, which slows down the rate at which fatty deposits build up in the blood vessels. | These need to be taken on a regular basis. They often have side effects such as muscle or joint pains, they can also cause liver or kidney problems |
| Stents | Single minor treatment which can increase the lumen of the blood vessel increasing blood flow to the heart muscle. | Small risk of damage to the blood vessel. As the skin needs to be pierced to reach blood vessel, small risk of infection. |
| Bypass surgery | If the blockage is large or there are multiple blockages, then bypass surgery can offer a better long term outcome compared to the use of stents. | The person needs to undergo major surgery, there is a long recovery time and increased risk of infection |
Practice Questions
1.Describe what is meant by the term coronary heart disease
2. State 3 ways which can be used to treat coronary heart disease
3. What could happen to a person if they have untreated coronary heart disease?