Question 1: Explain the main differences between arteries, veins, and capillaries in terms of structure and function.

Answer: Arteries have thick, elastic walls to withstand high pressure and carry blood away from the heart; veins have thinner walls, contain valves to prevent backflow, and carry blood towards the heart; capillaries are very thin, allowing exchange of substances between blood and tissues.

Question 2: Describe how the structure of capillaries enables their function in the circulatory system.

Answer: Capillaries are only one cell thick, which allows for efficient diffusion of gases, nutrients, and waste products between blood and tissues.

Question 1: Calculate the blood flow velocity in a capillary if the volumetric flow rate is 1.5 x 10^-9 cubic metres per second and the cross-sectional area of the capillary is 2 x 10^-8 square metres. Use the formula: velocity = flow rate / cross-sectional area.

Answer: Velocity = 0.075 m/s

Question 2: If the blood pressure in an artery is 120 mm Hg and the resistance to blood flow is 15 units, estimate the flow rate using the formula: Flow Rate = Pressure / Resistance. Express your answer in appropriate SI units.

Answer: Flow Rate ≈ 8 x 10^-3 cubic metres per second

Question 1: Design a simple experiment to investigate how blood vessel diameter affects blood flow velocity. List the variables involved and mention any safety precautions.

Answer: The experiment involves measuring blood flow velocity in vessels of different diameters using appropriate equipment such as a microscope and flow sensors. Variables include vessel diameter (independent), blood flow velocity (dependent), and blood pressure (controlled). Safety precautions involve handling blood samples safely, ensuring equipment is sterilised, and disposing of biological waste properly.

Question 1: A study reports that in individuals with hypertension, the average arterial blood pressure is 160 mm Hg, whereas in healthy individuals it is 120 mm Hg. Discuss how this difference impacts blood flow and vessel health.

Answer: Higher arterial pressure in hypertensive individuals increases the workload on blood vessels, potentially causing damage to vessel walls, leading to a higher risk of atherosclerosis, aneurysm, and impaired blood flow regulation.

Question 1: Explain how the structure of arteries is adapted for their role in high-pressure blood transport and how this differs from veins.

Answer: Arteries have thick, elastic walls with smooth muscle to withstand and maintain high pressure, and contain elastic fibres for recoil. Veins have thinner walls, less elastic tissue, and valves to prevent backflow, suitable for lower pressure and blood return to the heart.

Question 2: Identify and explain two ways in which blood vessel health can be maintained or improved in everyday life.

Answer: Maintaining a healthy diet low in saturated fats and cholesterol reduces the risk of atherosclerosis. Regular exercise helps improve blood circulation and vessel elasticity.