Question 1: Describe the primary function of the heart in the cardio-respiratory system during exercise.

Answer: The primary function of the heart during exercise is to pump oxygenated blood from the lungs to the muscles and deoxygenated blood back to the lungs for oxygenation. It increases the rate and force of beats to meet the increased demand for oxygen and nutrients.

Question 2: Explain how the lungs assist in the process of respiration during physical activity.

Answer: The lungs facilitate gas exchange by taking in oxygen from the air we breathe and transferring it to the blood, while removing carbon dioxide from the blood and expelling it during exhalation. During exercise, this process speeds up to supply more oxygen to the muscles.

Question 3: Identify and describe the role of the alveoli in the respiratory system.

Answer: Alveoli are tiny air sacs within the lungs where gas exchange occurs. They allow oxygen to diffuse into the blood and carbon dioxide to diffuse out, facilitating efficient respiration during physical activity.

Question 4: Describe the pathway of oxygen from the moment you breathe in until it reaches the muscles.

Answer: Oxygen enters through the nose or mouth, passes down the trachea, into the bronchi, then into the bronchioles, reaching the alveoli. In the alveoli, oxygen diffuses into the blood in the capillaries, where it binds to haemoglobin. The oxygen-rich blood is then pumped by the heart through arteries to the muscles.

Question 5: Sketch a diagram showing the main parts of the cardio-respiratory system involved in exercise. Label the heart, lungs, alveoli, and blood vessels.

Answer: A correct sketch would depict the heart centrally, connected to lungs via pulmonary arteries and veins. The lungs should show alveoli as small sacs, with blood vessels indicating oxygen exchange. Arteries and veins should be clearly labelled.

Question 6: Explain how increased physical activity affects the rate of breathing and heart rate.

Answer: During increased physical activity, both the breathing rate and heart rate increase to supply more oxygen to the muscles and remove carbon dioxide more efficiently. This is part of the body's response to meet higher energy demands.

Question 7: What is the significance of the capillaries surrounding the alveoli?

Answer: Capillaries surrounding the alveoli facilitate gas exchange by allowing oxygen to pass from the alveoli into the blood and carbon dioxide to pass from the blood into the alveoli for exhalation. They enable efficient transfer of gases due to their thin walls.

Question 8: Describe how the cardio-respiratory system adapts over time with regular aerobic training.

Answer: With regular aerobic training, the system adapts by increasing cardiac output, improving the efficiency of oxygen exchange in the lungs, and increasing the number and size of mitochondria in muscle cells. These adaptations enhance endurance and reduce fatigue.

Question 9: Identify the main blood vessels involved in transporting oxygenated blood from the lungs to the body.

Answer: The main blood vessel involved is the pulmonary vein, which carries oxygenated blood from the lungs to the heart. From the heart, the aorta distributes oxygen-rich blood to the body via arteries.

Question 10: Draw an outline diagram of the heart, indicating the four chambers and major blood vessels connected to it.

Answer: A correct sketch would show the heart with four chambers: two atria (upper chambers) and two ventricles (lower chambers). The diagram should include the aorta, pulmonary arteries, pulmonary veins, and the vena cava, all properly labelled.