Question 1: Define the process of inhalation in the context of the respiratory system.

Answer: Inhalation is the process where air is drawn into the lungs as the diaphragm and intercostal muscles contract, increasing the volume of the thoracic cavity.

Question 2: Describe the role of the diaphragm during exhalation.

Answer: During exhalation, the diaphragm relaxes and moves upwards into the chest cavity, reducing lung volume and helping expel air.

Question 3: Which muscles are primarily responsible for increasing the thoracic volume during breathing?

Answer: Diaphragm and intercostal muscles

Question 4: Fill in the blank: During inhalation, the pressure inside the lungs decreases because the volume of the thoracic cavity __________.

Answer: increases

Question 5: Explain how the movement of the diaphragm affects air pressure in the lungs.

Answer: When the diaphragm contracts and moves downward, the volume of the thoracic cavity increases, causing a decrease in air pressure inside the lungs relative to the outside air, which allows air to flow in. During relaxation, the diaphragm moves upward, decreasing lung volume and increasing pressure, pushing air out.

Question 6: Calculate the volume of air inhaled if a person takes in 15 breaths per minute with an average breath volume of 0.5 litres per breath.

Answer: 7.5 litres

Question 7: Identify two factors that could affect the efficiency of gas exchange in the lungs.

Answer: Thickness of the alveolar membrane and surface area of alveoli.

Question 8: Describe one safety precaution to consider when conducting a practical experiment on measuring lung capacity.

Answer: Ensure the use of sterile equipment to prevent infections and handle all apparatus carefully to avoid breakage.

Question 9: In a scenario, a person’s vital capacity is measured at 4.8 litres. If their tidal volume is 0.5 litres, how many breaths do they take to reach vital capacity?

Answer: 9.6 breaths

Question 10: Explain how the respiratory system adapts during exercise to meet increased oxygen demand.

Answer: During exercise, the respiratory rate and tidal volume increase to allow more oxygen to enter the lungs and carbon dioxide to be expelled more rapidly. The lungs may also increase in efficiency, and the heart rate rises to transport oxygenated blood to muscles more quickly, supporting sustained activity.