mistakes

• suggest a reason for the thickness of the walls of the atria and the ventricles

  Ventricles are thicker because they plump blood a further distance around entire body
• Explain how the semi-lunar valve helps to ensure a one-way flow of blood through the heart

  Valve opens when ventricle contract

  valve closes when ventricle contracts
• explain how an unbalanced diet and lack of exercise could lead to an atheroma formation

  Too much fat in diet builds up fatty deposits ; lack of exercise means fat is not used up as energy and is stored
• statin lowers blood cholesterol levels
• cardiovascular disease is caused when fatty deposits create an atheroma in the coronary arteries
• explain how an atheroma may lead to a heart attack

  coronary arteries blocked -> reduces blood flow to heart muscle -> reduces oxygen to heart muscle cells