The smoke of cigarettes has two parts: the particulate phase – tiny portions of solid matter that contain the tar; and the gas phase, which contains carbon monoxide and nitrogen oxides. These toxic substances are drawn directly into the smokers’ lungs. The filters in most cigarettes reduce the amount of large particles and allow some dilution with air, but let most of the harmful chemicals into the lungs.
The tar content of cigarette smoke damages the cells in the airway of the lung. Eventually this damage can produce cells that grow uncontrollably, leading to cancer of the larynx, or voice box.
Lung cancer is the disease of the smoker, with 90% of primary lung cancers caused by smoking. Nearly one in four smokers who die prematurely will die of lung cancer. Lung cancer is the biggest cancer killer in the UK. The risk of developing lung cancer is directly related to the number of cigarettes smoked. The cancer develops from cells within the lungs, the bronchi (air passages leading to the wind pipe) or the trachea (wind pipe). There are two main types of lung cancer: small cell lung cancer and non-small cell lung cancer. They differ in the way they develop and the treatment they need. Small cell lung cancer accounts for about one in five lung cancers, and tends to grow very quickly.
Healthy Lung Cancer Infected Lung
Cigarettes contain nitrosamines and other chemicals that increase the risk of cancer. When you smoke, you always swallow some of the smoke as well as breathing it into your lungs. This is why smoking is a major risk factor for oesophageal (gullet) cancer. About 2 in 5 cases of oesophageal cancer may be related to smoking. Oesophageal cancer develops in cells that line the oesophagus; that is the hollow tube that connects the throat with the stomach, and is part of the digestive system. If undiscovered, oesophageal cancer can spread to involve the stomach, lungs and liver, as well as nearby parts of the body's lymphatic system called lymph nodes.
Every time smoke from a cigarette is inhaled, some alveoli are killed. This is where the oxygen that you breathe in is transferred into the blood. The alveoli don’t grow back, so a part of your lungs is permanently destroyed.
Smoking paralyses the cilia that line the lungs.
Cilia are little hair like structures that move back and forth to sweep particles out of your lungs. When you smoke, the cilia can’t move and can’t do their job. So dust, pollen, and other things that are inhaled sit in the lungs and build up. The mucus collects in the bronchial tubes and this results in “smoker’s cough.” If the mucus becomes infected, you may get chronic bronchitis.
As a result of “smoker’s cough,” repeated coughing may cause the walls of the alveoli to break down into air spaces. This reduces the surface area over which gas exchange can take place, so you get short of breath. This condition is called emphysema, which ultimately is a life threatening illness.
