Overview
Definition
Chronic obstructive pulmonary disease or COPD is a group of lung diseases that reduce the ability of the lungs to oxygenate the blood. Emphysema and chronic bronchitis, which usually occur together, are the main diseases that make up COPD.
Almost 16 million Americans suffer from some form of chronic obstructive pulmonary disease. Emphysema is the most common COPD and the most deadly, ranking fourth as the leading cause of death in the United States, after heart disease, cancer and stroke.
Emphysema develops over many years. The tiny air sacs within the lungs (alveoli) are gradually destroyed, usually by cigarette smoke. As a result, the alveoli are not able to pick up enough oxygen for the lungs so sufferers become more and more short of breath.
As we breathe in air through our mouths and noses, the air travels through breathing tubules (bronchi) which get smaller and smaller. At the end of these tubules, there are air sacs (alveoli) where the oxygen from the air enters the blood.
Chronic bronchitis refers to an ongoing inflammation of the lining of the lung's breathing tubes (bronchi) caused by bacterial infection and, usually, smoke irritation. As the inflammation gets worse, the bronchi fill with mucus and grow narrower, making it harder for air to flow. This results in a chronic cough, as the body attempts to rid itself of the excess mucus that is irritating the lungs. This mucus is also known as phlegm or sputum.
More on Chronic Obstructive Pulmonary (Lung) Diseases What Is Emphysema?
COPD: Are You at Risk?
In the Encyclopedia: Cough
This article was reviewed and updated June 2007.
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