Question 1: Define coronary heart disease and describe the main cause of this condition.

Answer: Coronary heart disease is a condition where the coronary arteries become narrowed or blocked, primarily due to atherosclerosis caused by the build-up of fatty deposits, cholesterol, and plaque.

Question 2: Explain how the build-up of fatty deposits in the coronary arteries affects blood flow to the heart muscle.

Answer: The build-up of fatty deposits narrows the arteries, reducing blood flow, which limits oxygen and nutrient supply to the heart muscle, increasing the risk of a heart attack.

Question 3: What is atherosclerosis and how does it relate to coronary heart disease?

Answer: Atherosclerosis is the build-up of fatty deposits, cholesterol, and plaque within the artery walls, which causes narrowing and hardening of the arteries, leading to coronary heart disease.

Question 4: Calculate the reduction in blood flow if the diameter of a coronary artery decreases from 4 mm to 2 mm due to plaque build-up. (Hint: use the relationship that flow is proportional to the fourth power of the radius).

Answer: Flow reduction factor = (radius after / radius before)^4 = (1 mm / 2 mm)^4 = (0.5)^4 = 0.0625. Therefore, blood flow is reduced to 6.25% of its original flow.

Question 5: List three lifestyle factors that can increase the risk of developing coronary heart disease.

Answer: Poor diet high in saturated fats, lack of physical activity, smoking, and excessive alcohol consumption.

Question 6: Identify and explain two common treatments used to manage coronary heart disease.

Answer: Treatments include the use of statins to lower cholesterol levels and coronary artery bypass surgery to improve blood flow by creating new pathways around blocked arteries.

Question 1: A study shows that individuals with a total cholesterol level above 6 mmol/L are twice as likely to develop coronary heart disease compared to those with levels below 5 mmol/L. Explain how high cholesterol contributes to the development of coronary heart disease.

Answer: High cholesterol levels lead to the accumulation of fatty deposits in the coronary arteries, forming plaques that narrow the arteries and restrict blood flow. This increases the risk of plaque rupture and blood clots, which can cause heart attacks.

Question 1: Describe a simple experimental procedure to investigate the effect of a high-fat diet on cholesterol levels in rats. Include variables to control and safety precautions.

Answer: The experiment involves dividing rats into two groups: one fed a normal diet and the other a high-fat diet. Variables include diet type (independent), cholesterol level (dependent), and environmental conditions (controlled). Safety precautions include handling animals ethically, ensuring proper housing, and avoiding overfeeding or stress.

Question 1: Explain how statins work to reduce the risk of coronary heart disease and discuss one potential side effect.

Answer: Statins inhibit the enzyme responsible for producing cholesterol in the liver, thereby lowering blood cholesterol levels. A potential side effect is muscle pain or damage.

Question 2: Discuss how public health campaigns can help reduce the incidence of coronary heart disease.

Answer: Public health campaigns can promote healthy lifestyles by encouraging balanced diets low in saturated fats, increased physical activity, smoking cessation, and regular health screenings, which help in early detection and prevention.