Risk factors associated with coronary heart disease: diet, blood cholesterol, cigarette smoking and high blood pressure. Candidates should be able to describe and explain data relating to the relationship between specific risk factors and the incidence of coronary heart disease

A number of factors can increase the risk of coronary heart disease:

Diet

• Salt raises blood pressure.
• Saturated fat increases blood cholesterol.

Blood cholesterol

• Low-density lipoproteins associate with white blood cells to cause atheromas.
• High-density lipoproteins help lower cholesterol.

Smoking

• Nicotine stimulates the production of adrenalin, this causes a quicker heart rate and therefore raises the blood pressure.
• Nicotine makes platelets stick together, so thrombosis is more likely.
• Carbon monoxide combines with heamaglobin so less oxygen can be carried in the blood. The heart has to pump more quickly to deliver the same amount of oxygen, so blood pressure is raised. The heart muscles may not get enough oxygen leading to a heart attack or angina (chest pain).

High blood pressure

• Arteries are put under more pressure so will form hard walls to resist the pressure- these thicker walls constrict blood flow.
• The pressure can burst open the arteries (haemorrhage).

Atheroma as the presence of fatty material within the walls of arteries. The link between atheroma and the increased risk of aneurysm and thrombosis. Myocardial infarction and its cause in terms of an interruption to the blood flow to heart muscle.

Atheroma is the name given to fatty build ups in artery walls: consisting of cholesterol, fibres, dead cells and white blood cells attached to fats.

Aneurysm
This is when an atheroma weakens an artery wall and it swells with blood making an aneurysm. If it bursts (haemorrhage) blood is lost- this can be fatal. In the brain this is what we know as a stroke.

Thrombosis
When an atheroma bursts the lining of an artery (endothelium) and obstructs blood flow. A clot (thrombus) can form here and block the vessel, or be carried around the body and block another vessel. The blocked off area doesn't receive oxygen so will die.

Myocardial infraction
This is a heart attack. A blockage stops blood getting to the heart tissue; the tissue doesn't receive enough oxygen and so gets damaged. The damage prevents the heart from pumping properly.

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