Question 1: Coronary Heart Disease (CHD) occurs when the coronary arteries become narrowed or blocked, reducing blood flow to the heart muscle. This can lead to chest pain, heart attacks, and other complications. The primary cause is a build-up of fatty deposits called plaque.

Answer: Coronary Heart Disease is a condition where the coronary arteries are narrowed or blocked by plaque, reducing blood flow to the heart.

Question 1: Define atherosclerosis and explain its role in CHD.

Answer: Atherosclerosis is the build-up of fatty deposits (plaque) inside the arteries, which narrows the arteries and can lead to CHD.

Question 2: Describe how lifestyle factors such as diet and exercise influence the risk of developing CHD.

Answer: A healthy diet and regular exercise reduce risk factors like high blood cholesterol and hypertension, thus lowering the risk of CHD.

Question 1: Calculate the Body Mass Index (BMI) for a person weighing 70 kg and with a height of 1.75 m. Use the formula: BMI = weight (kg) / height² (m²).

Answer: BMI = 70 / (1.75)^2 = 22.86

Question 2: A patient has a total cholesterol level of 6.5 mmol/L. If the recommended maximum level is 5 mmol/L, calculate the excess cholesterol in mmol/L.

Answer: Excess = 6.5 - 5 = 1.5 mmol/L

Question 3: If a person’s blood pressure reading is 140/90 mmHg, what is the mean arterial pressure (MAP)? Use the formula: MAP = diastolic + 1/3(systolic - diastolic).

Answer: MAP = 90 + 1/3(140 - 90) = 90 + 16.67 = 106.67 mmHg

Question 1: Design a simple experiment to test the effect of a high-fat diet on blood cholesterol levels in rats. Include variables and safety precautions.

Answer: The experiment involves dividing rats into two groups: one fed a high-fat diet and the other a normal diet. The independent variable is diet type; the dependent variable is blood cholesterol level. Control variables include age and weight of rats. Safety precautions include handling of animals ethically, proper disposal of animal waste, and avoiding contamination of samples.

Question 1: A study reports that individuals with a BMI over 30 have a 2.5 times higher risk of developing CHD than those with a BMI under 25. Explain what this suggests about the relationship between BMI and CHD risk.

Answer: It suggests that higher BMI levels are associated with an increased risk of CHD, indicating that obesity is a significant risk factor.

Question 1: Explain how the build-up of plaque in coronary arteries leads to reduced blood flow and increases the risk of heart attack. (6 marks)

Answer: Plaque accumulation narrows the coronary arteries, reducing blood flow to the heart muscle. This limits oxygen and nutrient supply, which can cause angina. If a plaque ruptures, a blood clot may form, completely blocking the artery, leading to a heart attack.

Question 1: Describe how advancements in medical technology, such as stent placement, help in managing CHD.

Answer: Stents are inserted into blocked arteries to widen them and restore blood flow, reducing the risk of heart attack and improving patient outcomes.