AS biology King Alfred's Academy : November 2013

Lung disease and ventilation questions- due Tuesday 19th

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.

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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.

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.

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

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.

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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)

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)

Other lung function acronyms:

TLC	Total lung capacity: the volume in the lungs at maximal inflation
RV	Residual volume: the volume of air remaining in the lungs after a maximal exhalation
ERV	Expiratory reserve volume: the maximal volume of air that can be exhaled from the end-expiratory position
IRV	Inspiratory reserve volume: the maximal volume that can be inhaled from the end-inspiratory level
IC	Inspiratory capacity: the sum of IRV and TV
IVC	Inspiratory vital capacity: the maximum volume of air inhaled from the point of maximum expiration
VC	Vital capacity: the volume equal to TLC − R
VT	Tidal volume: that volume of air moved into or out of the lungs during quiet breathing (VT indicates a subdivision of the lung; when tidal volume is precisely measured, as in gas exchange calculation, the symbol VT or VT is used.)
FRC	Functional residual capacity: the volume in the lungs at the end-expiratory position
RV/TLC%	Residual volume expressed as percent of TLC
VA	Alveolar gas volume
VL	Actual volume of the lung including the volume of the conducting airway.
FVC	Forced vital capacity: the determination of the vital capacity from a maximally forced expiratory effort
FEV1	Volume that has been exhaled at the end of the first second of forced expiration
FEFx	Forced expiratory flow related to some portion of the FVC curve; modifiers refer to amount of FVC already exhaled
FEFmax	The maximum instantaneous flow achieved during a FVC maneuver
FIF	Forced inspiratory flow: (Specific measurement of the forced inspiratory curve is denoted by nomenclature analogous to that for the forced expiratory curve. For example, maximum inspiratory flow is denoted FIFmax. Unless otherwise specified, volume qualifiers indicate the volume inspired from RV at the point of measurement.)
PEF	The highest forced expiratory flow measured with a peak flow meter
MVV	Maximal voluntary ventilation: volume of air expired in a specified period during repetitive maximal effort