To understand what happens to the airways and lungs of people with chronic bronchitis and emphysema it is useful to know how healthy lungs work.

Each time you breathe, air is drawn, via the nose and mouth, into the windpipe or trachea. The windpipe is a tube about 10-12 centimetres long in adults and splits into two smaller tubes that go to the left and right lungs. Each of these tubes is called a bronchus. They divide into smaller and smaller airways, and together they are called bronchi. The air passes down the bronchi in each lung, dividing another 15-25 times into smaller and smaller airways called bronchioles. The smallest airways end in tiny air sacs called alveoli. It is here that the oxygen from the air is absorbed into tiny blood vessels called capillaries which criss cross the walls of the alveoli.

Once it passes into the blood stream, oxygen is carried all around the body, and at the same time a waste product, called carbon dioxide, comes out of the capillaries back into the alveoli ready to be breathed out.

If you could look inside your lungs, you would see a mass of fine tubes and air pockets, all looking rather like a giant sponge.

What happens in emphysema?

In emphysema, the alveoli or airsacs in the lungs are gradually destroyed so people have difficulty absorbing enough oxygen. The bronchi becomes floppy and narrow so that it becomes harder to breathe in and out.

These days, the most common cause of emphysema is cigarette smoking. Industrial pollutants may also cause emphysema. 

What happens in chronic bronchitis? 

Bronchitis means inflammation of the bronchi. As a result mucus which is normally made in the airways to keep them moist, is produced in excessive amounts. This leads to cough and sputum production. The bronchi may also become narrow and floppy (making them narrower) and therefore it is harder for air to get in and out of the lungs. Breathlessness results.

Most adults have a bout of 'acute' or short-term bronchitis at some time in their lives, lasting a week or two at the most. In chronic bronchitis, however, people produce a lot of mucus, sometimes called phlegm and they cough and are breathless for months or even years.

How do people feel?

In mild forms of these diseases, breathlessness may occur walking up hills or stairs, but in severe cases, breathlessness can occur walking slowly along flat ground. Normally daily activities become more difficult as the disease gets worse.

It is not surprising that people with chronic bronchitis and emphysema may become frustrated, anxious and depressed, making breathing problems worse. People who feel more positively toward life tend to do better.

Adapting to the limitations placed on lifestyle, together with the care and support of family and friends, can do a lot to relieve anxiety and lift depression.

Other problems

People with chronic bronchitis and emphysema are more prone to chest infections and pneumonia and occasionally require admission to hospital for intensive treatment of their disease. During these episodes they may have a low oxygen level in the blood and develop swollen ankles because of inadequacy of the pumping action of the heart.

Content updated October 21, 2010