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
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.
Use information in the passage and your own knowledge to answer the
following questions.
6 (a) Destruction of phagocytes (lines 4–5) causes the lungs to be more susceptible to
infections. Explain why