Smoking and health

Attitudes to smoking

Over the last few decades, people's attitudes to smoking have changed. -Fewer people are smoking. -People are more aware of the effects of passive smoking. -Smoking bans have been introduced in public places. -Cigarette packets carry health warnings. -The age limit for buying cigarettes has been raised from 16 to 18. -Products and support groups exist to help people to stop smoking. -Pregnant women now rarely smoke - they are aware of possible damage to their babies.

How smoking causes disease

Smoking causes lung cancer and emphysema because: -Tobacco smoke contains many chemicals that are carcinogens (they cause cancer). This provides a clear link with lung cancer. -Tobacco smoke damages the cilia that line the lungs, paralysing them and causing them to eventually die off. The lungs become clogged by mucus and irritated by the particles trapped in the mucus. This explains the development of emphysema. -Tobacco smoke contains tar which clogs up the lungs and makes it more difficult to breathe, which again can lead to emphysema. The vast majority of scientists are now certain that smoking is potentially very harmful to the smoker, and also to people in the vicinity who breathe in the smoke (passive smoking). The evidence is mainly disputed by groups with an obvious bias (e.g. studies paid for by the tobacco industry). The reasons we can be confident that smoking is linked with lung disease are: -Many studies have shown the link - the data has been reproducible. -These studies have been peer reviewed - other scientists have checked the methods and the results.

Lung cancer and emphysema

Smoking cigarettes or other tobacco products is a major cause of lung cancer and emphysema. -Lung cancer is a disease that is difficult to treat and often causes death. Tumours grow in the lungs and may spread to other parts of the body via the blood stream, as the lungs have a very good blood supply. -Emphysema is caused by inflammation and scarring of lung tissue, and same to the alveoli. A person with emphysema has a persistent cough and finds it difficult to breathe.

Smoking and the lungs

The lining of the respiratory system produces sticky mucus. This traps dust and bacteria from the air breathed in. The cells lining the trachea and bronciholes have delicate hair-like structures called cilia, which move, constantly shifting the mucus to the top of the trachea, whereit is swallowed. Inhalation of smoke causes paralysis of the cilia. The mucus and trapped paricles will the. Sink into the lungs, causing irritation, damaging the lung tissue and increasing the risk of disease.