Describe how the coronary arteries can become narrowed and explain how this can lead to a heart attack.

Eating a diet high in saturated fat has been linked to high levels of cholesterol in the blood.If there is too much cholesterol in the blood it can start to build up in the coronary arteries. This causes plaques to form in the artery walls. Plaques narrow the arteries and restrict the flow of blood.The coronary arteries can become narrowed through the formation of plaques.Narrowed coronary arteries can lead to a heart attack. This is because blood flow to the heart is restricted and the heart muscle receives less oxygen.A thrombosis (blood clot) may further restrict or block blood flow.If the flow of blood to the heart is completely blocked, an area of the heart will be cut off from its oxygen supply. This can cause a heart attack.