The
graph shows the pattern of breathing in a person sitting at rest.
(a) (i) What
is the name given to the volume of air labelled A?
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(1)
(ii) Explain how you would calculate the volume
of air taken into the lungs in one minute.
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(1)
One way in which hospitals test how
well the lungs are working is to measure the gas transfer factor. This is done
by measuring the uptake of carbon monoxide from a single breath of air
containing 0.3% carbon monoxide.
(b) (i) By
what process would carbon monoxide pass from the air in the alveoli to the
blood in the lung capillaries?
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(1)
(ii) Suggest why carbon monoxide is used for
this test.
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(2)
(c) Interstitial lung disease is a disease in
which the alveolar walls become thicker.
Explain why the gas transfer factor would be low in a person who had interstitial lung disease.
Explain why the gas transfer factor would be low in a person who had interstitial lung disease.
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(1)
(Total 6 marks)
Read
the following passage.
Several diseases are caused by
inhaling asbestos fibres. Most of these
diseases result from the build up of these tiny asbestos fibres in the lungs.
diseases result from the build up of these tiny asbestos fibres in the lungs.
One of these diseases is asbestosis.
The asbestos fibres are very small and
enter the bronchioles and alveoli. They cause the destruction of phagocytes
and the surrounding lung tissue becomes scarred and fibrous. The fibrous 5
tissue reduces the elasticity of the lungs and causes the alveolar walls to
thicken. One of the main symptoms of asbestosis is shortness of breath
caused by reduced gas exchange.
enter the bronchioles and alveoli. They cause the destruction of phagocytes
and the surrounding lung tissue becomes scarred and fibrous. The fibrous 5
tissue reduces the elasticity of the lungs and causes the alveolar walls to
thicken. One of the main symptoms of asbestosis is shortness of breath
caused by reduced gas exchange.
People with asbestosis are at a
greater risk of developing lung cancer. The time
between exposure to asbestos and the occurrence of lung cancer is 20–30 years. 10
between exposure to asbestos and the occurrence of lung cancer is 20–30 years. 10
Use information in the passage and
your own knowledge to answer the following questions.
(a) Destruction of phagocytes (lines 4–5)
causes the lungs to be more susceptible to infections. Explain why.
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(2)
(b) (i) The
reduced elasticity of the lungs (lines 6–7) causes breathing difficulty.
Explain how.
Explain how.
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(2)
(ii) Apart from reduced elasticity, explain how
changes to the lung tissue reduce the efficiency of gas exchange.
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(4)
(c) (i) Doctors
did not make the link between exposure to asbestos and an increased risk of
developing lung cancer for many years. Use information in the passage to
explain why.
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(1)
(ii) Give one factor, other than
asbestos, which increases the risk of developing lung cancer.
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(1)
(Total 10 marks)
Miner’s
lung is a disease caused by breathing in dust in coal mines. The dust causes
the alveolar epithelium to become thicker. People with miner’s lung have a
lower concentration of oxygen in their blood than healthy people.
(a) (i) Describe
the path by which oxygen goes from an alveolus to the blood.
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(2)
(ii) Explain why people with miner’s lung have a
lower concentration of oxygen in their blood.
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(1)
(b) In healthy lungs, a gradient is maintained
between the concentration of oxygen in the alveoli and the concentration of
oxygen in the lung capillaries.
(i) Describe how ventilation helps to maintain
this difference in oxygen concentration.
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(2)
(ii) Give one other way that helps to
maintain the difference in oxygen concentration.
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(1)
(c) Scientists investigated the number of cases
of miner’s lung reported in Britain between 1992 and 2006.
Coal mining in Britain had been
dramatically reduced by 1990.
Some scientists concluded that the
rise in reported cases of miner’s lung after 1992 shows that the disease takes
a long time to develop.
Evaluate this conclusion.
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(2)
(Total 8 marks)
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