Smoking and lung disease

Question

Why can smoking cause lung diseases?

Answer

Smoking cigarettes significantly increases the risk of contracting a lung disease (Hanania and Sharafkhaneh, 2011). The human respiratory system comprises the nose, upper airway and alveolar surface of the lungs (the point at which gas exchange occurs) (Barnes et al. 2009). During tobacco smoking, harmful toxins within the smoke are inhaled through the upper airway and reach this gas exchange surface. As the smoke moves through the respiratory tract, significant concentrations of carcinogens and toxins are delivered and deposited to these sites. The high concentrations of harmful substances which reach these areas can, over time, cause serious damage to the structure of the airways resulting in a range of lung diseases (Barnes et al. 2009).

Chronic Obstructive Pulmonary Disease (COPD) is the most abundant non-malignant respiratory disease caused by smoking and covers multiple symptoms which include emphysema, chronic bronchitis and asthma (Hanania and Sharafkhaneh, 2011). As the name suggests, COPD presents as an obstruction of the patient’s airflow, which makes breathing significantly harder, due to a range of pathology caused by the deposition and long term effects of toxic and carcinogenic substances inhaled through smoking. Emphysema causes an increase in the distal space to terminal bronchioles (the space which oxygen has to pass to enter the blood) and destruction of the cell walls leading to a lesser gas exchange surface area. Whilst Chronic Bronchitis, is characterised by a hyper production of mucus and inflammation of the bronchial tubes (the tubes which carry the oxygen to the lungs) (Barnes et al. 2009).

References

Barnes, P.J. Barnes, J. Drazen, J.M, Rennard, S.I. (2009) Asthma and COPD, 2nd Edition, London: Elsevier Limited

Hanania, N.A. Sharafkhaneh, A. (2011) COPD: A Guide to Diagnosis and Clinical Management, London: Springer