Gas Exchange In Humans

9.What is the role of cilia in the breathing system?

10.Which structure is the gas exchange surface in humans?

11.Which of the following is NOT a feature that makes alveoli efficient gas exchange surfaces?

12.The diagram shows the human breathing system. Which structure is the trachea?

13.In an investigation, a student breathes in and out through the apparatus shown. Boiling tube A contains limewater through which air is drawn during inhalation. Boiling tube B contains limewater through which exhaled air is blown. What is the expected result after several breaths?

14.The table shows the composition of inspired and expired air. | Gas | Inspired air / % | Expired air / % | |---|---|---| | Oxygen | 21 | 16 | | Carbon dioxide | 0.04 | 4 | | Water vapour | 0.2–4 | 1–5 | | Nitrogen | 78 | 78 | Which gas shows the largest percentage decrease from inspired to expired air?

15.During exercise, the depth of breathing increases. What is the most likely reason for this?

16.A student counts their breaths per minute at rest and then after 5 minutes of exercise. The results are shown in the graph. What is the percentage increase in breathing rate from rest to immediately after exercise? (Rest: 12 breaths/min, After exercise: 24 breaths/min)

17.Which of the following is a correct description of the action of the diaphragm during inhalation?

18.What is the function of the rings of cartilage in the trachea?

19.In a study, the number of people with COPD in cities and villages was compared. The data showed that 15% of city dwellers and 8% of village dwellers had COPD. What is the ratio of city to village COPD prevalence?

20.Which of the following is a feature of alveoli that makes them efficient for gas exchange?

21.The diagram shows a section through an alveolus and a surrounding capillary. Which structure is the site of gas exchange?

22.Which cells produce mucus in the breathing system?

23.A student measures chest expansion at rest and after exercise. At rest, the chest circumference increases by 2 cm during inhalation. After exercise, it increases by 4 cm. What does this indicate?

24.In an investigation to compare the carbon dioxide content of inhaled and exhaled air, a student uses the apparatus shown. Air is drawn through boiling tube A during inhalation and blown into boiling tube B during exhalation. Both tubes contain limewater. After several breaths, the limewater in tube B turns cloudy, while tube A remains clear. What is the correct conclusion?

25.A student investigates the effect of exercise on breathing rate. They count breaths per minute at rest (12 breaths/min) and after 5 minutes of exercise (30 breaths/min). What is the percentage increase in breathing rate?

26.In an experiment to investigate the effect of physical activity on breathing, which two measurements should be taken before and after exercise?

27.A student uses a tape measure to measure chest expansion at rest and after exercise. At rest, the chest circumference increases by 3 cm during deep inhalation. After running for 5 minutes, the chest expansion is 5 cm. Which conclusion is most valid?

28.Which of the following is a limitation of using chest expansion as a measure of breathing depth?

29.During forced exhalation, which muscles contract to pull the ribs down and in?

30.During inhalation, which of the following occurs?

31.In an experiment, a student uses a spirometer to measure lung volumes. The trace shows a tidal volume of 0.5 L and a vital capacity of 4.5 L. What is the inspiratory reserve volume if the expiratory reserve volume is 1.5 L?

32.Which of the following best explains why breathing rate increases during exercise?

33.A student measures chest expansion at rest and after exercise. At rest, the chest circumference increases by 2 cm during deep inhalation. After exercise, it increases by 4 cm. What is the percentage increase in chest expansion?

34.The table shows the composition of inspired and expired air. | Gas | Inspired air / % | Expired air / % | |---|---|---| | Oxygen | 21 | 16 | | Carbon dioxide | 0.04 | 4 | | Water vapour | 0.2–4 | 1–5 | | Nitrogen | 78 | 78 | Which gas shows the largest percentage increase from inspired to expired air?

35.During exercise, a person's breathing rate increases from 12 breaths per minute to 30 breaths per minute, and tidal volume increases from 500 cm³ to 1500 cm³. What is the total volume of air breathed in per minute after exercise?

36.A student investigates the effect of exercise on breathing by counting breaths per minute at rest (12 breaths/min) and after 5 minutes of exercise (30 breaths/min). They also measure chest expansion. Which of the following is a limitation of using chest expansion as a measure of breathing depth?

37.Which of the following is the gas exchange surface in humans?

38.The percentage of carbon dioxide in expired air is higher than in inspired air.

39.Which of the following are features of all gas exchange surfaces? (Select all that apply)

40.Arrange the following events during inhalation in the correct order: 1. Air rushes into lungs 2. Volume of thorax increases 3. External intercostal muscles contract 4. Pressure in thorax decreases 5. Diaphragm contracts and flattens

41.Match each structure with its function.

42.Match each structure of the breathing system with its correct function.

43.Arrange the following events during inhalation in the correct order starting with the first event.

44.The percentage of nitrogen in expired air is the same as in inspired air.

45.During forced exhalation, which muscles contract?

46.A student breathes into a bag and then tests the air in the bag with limewater. The limewater turns cloudy. Which gas is present in higher concentration in the bag compared to atmospheric air?

47.Complete the sentence about the composition of inspired and expired air.

48.A person at rest breathes 12 times per minute with a tidal volume of 500 cm³. What is the total volume of air breathed in per minute in cm³?

49.State two ways in which the composition of expired air differs from inspired air.

50.Complete the sentence about the composition of air.

51.A person at rest breathes 15 times per minute with a tidal volume of 400 cm³. What is the total volume of air breathed in per minute? Give your answer in cm³.

52.Explain how the breathing rate increases during exercise.

53.A person at rest breathes 12 times per minute with a tidal volume of 500 cm³. What is the total volume of air breathed in per minute in cm³?

54.A person at rest breathes 15 times per minute with a tidal volume of 400 cm³. What is the total volume of air breathed in per minute? Give your answer in cm³.