As you breathe, air is drawn into the nose and/or mouth then passes through the back of your throat and into the windpipe (trachea). The trachea then divides into two bronchi, which are like branches, and these lead to the left and right lungs.

Air passes down the bronchi, which divide into even further branches and into smaller airways called bronchioles. At the end of these are tiny air sacs called alveoli, where oxygen and carbon dioxide pass to and from the bloodstream through tiny blood vessels.

The left lung has two lobes, the upper and lower lobes, and the right lung has three lobes, the upper, middle and lower lobes.

What are the most common types of lung disease?

  • Asthma is a temporary narrowing of the airways (bronchi) that causes sudden shortness of breath, wheezing and a tight feeling in the chest.
  • Bronchitis is a condition where the bronchi are inflamed and an excessive amount of mucus is produced, causing increased coughing. The bronchi may also become narrower, making it harder for air to get in and out of the lungs and leading to breathlessness.
  • Cancer is a disease of the cells that make up the organs and tissue of the body. Some common symptoms of lung cancer are a persistent cough, a chest infection that does not get better and shortness of breath. A chest X-ray may show abnormalities in the lung and pleura (lining of the lung and chest wall) but a doctor may request further tests to make a diagnosis of lung cancer.
  • Emphysema is caused by an over-stretching of the alveoli in the lungs and results in the lungs not working as well as they should. Cigarette smoking is the most common cause of emphysema. However, industrial pollutants can also be responsible.
  • Fibrosing alveolitis occurs when the alveoli become inflamed and scarred. The condition leads to shortness of breath. Treatment is usually a combination of steroids and immunosuppressants (medication which suppresses the body's defence mechanism) and physiotherapy.
  • Sarcoidosis is a condition that most commonly affects the lungs, skin and eyes. It can cause breathlessness, a dry cough in the lungs, or fever and joint pains throughout the body. Symptoms often clear up after a few weeks and treatment is usually with steroids. Only a small proportion of people will need long-term treatment.

What causes lung disease?

The causes of some lung diseases are not yet fully understood. However, we do know that cigarette smoking and some industrial products cause lung and heart disease.


Cigarette smoking is known to be the major cause of almost all heart and lung disease, including cancer.

The risk of developing heart or lung disease increases with the amount and the length of time that you smoke. Low tar cigarettes, cigars and pipes are harmful too - there is no such thing as safe smoking. If you smoked before your operation, this is likely to have contributed to your illness.

Your stay with us will give you a valuable opportunity to stop smoking. If you stop smoking your risk of developing heart or lung disease is reduced. After fifteen years as a non-smoker, your risk of getting lung cancer is the same as that of a person who has never smoked.

Passive smoking (inhaling smoke from other people’s cigarettes) is also now recognised as a factor that contributes to the development of heart and lung disease. After any chest surgery, your long-term recovery will be influenced by whether or not you smoke cigarettes and whether people around you smoke.

If members of your family smoke, please ask them to support you and improve their own health by stopping too. If people smoke in your home you may wish to consider making part or all of it a no-smoking environment.

For advice about stopping smoking talk to your pharmacist or GP. Our hospital also has a smoking cessation clinic to help patients quit. To join it patients need to be referred by their medical team or in some cases a GP.  Ask your team, or read our information for referring doctors.

Industrial causes

Many industrial processes and products, especially asbestos, are now recognised as causes of lung disease. However, the damage caused may take many years to become obvious. 

Read more about occupational lung disease

Lung function tests

We have a number of tests that we use to look at lung function, and how your lungs are functioning in aspects of your breathing and exercise. 

Lung function unit

Fulham wing/South block, Fulham Road

Tel: +44 (0)20 7351 8910
Fax: +44 (0)20 7351 8080