Gas Exchange in the Lungs Exam 2025–2026
Accurate Real Exam Questions and Verified
Correct Answers JUST RELEASED
Describe and explain how the lungs are adapted to allow rapid exchange of oxygen
between air in the alveoli and in the capillaries around them - answer>>>- Many alveoli
and folded walls provide a large surface area
- Many capillaries provide a large surface area
- Ventilation and circulation maintains a concentration gradient
- Alveoli and capillary walls only a single layer of epithelial/endothelial cells thick so there
is a short diffusion path
- All these factors make diffusion faster
A graph shows time on the x-axis and total volume of air breathed out on the y-axis. Curve
A shows the total volume of air breathed out before using an asthma inhaler and the
other higher curve B shows the volume after using the inhaler. Explain how you could use
the curve A to find the total volume of air the person could breathe out - answer>>>-
Extend/extrapolate curve
- Read off where the curve flattens
Explain how without an inhalor dilating bronchioles there is a lower total volume of air
breathed out in an asthma patient - answer>>>- Without an inhalor bronchioles are not
dilated
- Muscle surrounding the bronchioles contracts
- Less air is able to pass through them
Name the process by which oxygen passes from an alveolus in the lungs into the blood -
answer>>>- Diffusion
Describe two adaptations of the structure of the alveoli for efficient gas exchange -
answer>>>- Thin walls/one cell thick
- Total surface area is large
, Fire-breathers inhale mist, which can lead to fibrosis. Explain why people who have been
fire-breathers for years often find they cannot breathe out properly - answer>>>- Loss of
elastic tissue/elastin
- Scar tissue
- Less recoil
Explain how ventilation increases the rate of gas exchange in the alveoli - answer>>>-
Maintains a concentration gradient
- Faster and continuous diffusion
Describe what happens to the lungs during inspiration - answer>>>- Lungs increase in
volume and fill with air
Use Fick's law to explain how breathing results in efficient uptake of oxygen from the
lungs - answer>>>- Fick's law relates the rate of diffusion to difference in concentration
- Breathing replenishes oxygen in the lungs
- Maintains a difference in concentration
Explain two ways in which changes in the contraction of the diaphragm muscle affect
pulmonary ventilation - answer>>>- Contracts more rapidly
- Increases breathing rate
- Contracts for longer
- Increases depth of breathing and thus tidal volume
Use your knowledge of Fick's law to describe how lungs of a mammal are adapted to gas
exchange - answer>>>- Fick's law is the rate of diffusion proportional to surface area x
difference in concentration/thickness of exchange surface
- Many small alveoli
- Many capillaries
- Concentration difference maintained by ventilation
- Concentration difference maintained by circulating blood
- Short diffusion pathway between lumen and blood as red blood cells are flattened and
single layer of epithelial/endothelial cells on alveoli/capillary
Accurate Real Exam Questions and Verified
Correct Answers JUST RELEASED
Describe and explain how the lungs are adapted to allow rapid exchange of oxygen
between air in the alveoli and in the capillaries around them - answer>>>- Many alveoli
and folded walls provide a large surface area
- Many capillaries provide a large surface area
- Ventilation and circulation maintains a concentration gradient
- Alveoli and capillary walls only a single layer of epithelial/endothelial cells thick so there
is a short diffusion path
- All these factors make diffusion faster
A graph shows time on the x-axis and total volume of air breathed out on the y-axis. Curve
A shows the total volume of air breathed out before using an asthma inhaler and the
other higher curve B shows the volume after using the inhaler. Explain how you could use
the curve A to find the total volume of air the person could breathe out - answer>>>-
Extend/extrapolate curve
- Read off where the curve flattens
Explain how without an inhalor dilating bronchioles there is a lower total volume of air
breathed out in an asthma patient - answer>>>- Without an inhalor bronchioles are not
dilated
- Muscle surrounding the bronchioles contracts
- Less air is able to pass through them
Name the process by which oxygen passes from an alveolus in the lungs into the blood -
answer>>>- Diffusion
Describe two adaptations of the structure of the alveoli for efficient gas exchange -
answer>>>- Thin walls/one cell thick
- Total surface area is large
, Fire-breathers inhale mist, which can lead to fibrosis. Explain why people who have been
fire-breathers for years often find they cannot breathe out properly - answer>>>- Loss of
elastic tissue/elastin
- Scar tissue
- Less recoil
Explain how ventilation increases the rate of gas exchange in the alveoli - answer>>>-
Maintains a concentration gradient
- Faster and continuous diffusion
Describe what happens to the lungs during inspiration - answer>>>- Lungs increase in
volume and fill with air
Use Fick's law to explain how breathing results in efficient uptake of oxygen from the
lungs - answer>>>- Fick's law relates the rate of diffusion to difference in concentration
- Breathing replenishes oxygen in the lungs
- Maintains a difference in concentration
Explain two ways in which changes in the contraction of the diaphragm muscle affect
pulmonary ventilation - answer>>>- Contracts more rapidly
- Increases breathing rate
- Contracts for longer
- Increases depth of breathing and thus tidal volume
Use your knowledge of Fick's law to describe how lungs of a mammal are adapted to gas
exchange - answer>>>- Fick's law is the rate of diffusion proportional to surface area x
difference in concentration/thickness of exchange surface
- Many small alveoli
- Many capillaries
- Concentration difference maintained by ventilation
- Concentration difference maintained by circulating blood
- Short diffusion pathway between lumen and blood as red blood cells are flattened and
single layer of epithelial/endothelial cells on alveoli/capillary
