Breathing for most of us is something we do without being aware of it. We pay no attention to this continuous activity as we work, play, or sleep. Our lungs are responsible for this essential natural function that gets oxygen into the bloodstream so that it can be delivered to the cells of our body.
During a normal day, we breathe nearly 25,000 times. The more than 10,000 liters of air we inhale is mostly oxygen and nitrogen. In addition, there are small amounts of other gases, floating bacteria, and viruses. It also contains the products of tobacco smoke, automobile exhaust, and other pollutants from the atmosphere in varying amounts.
Air pollutants can affect our lungs in many ways. they may simply cause irritation and discomfort. But sometimes inhaled materials can cause illness or death. The lungs have a series of built-in mechanical and biological barriers that keep harmful materials from entering the body. In addition, specific defense mechanisms can inactivate some disease-causing materials.
A little lung history...
Nearly 2,000 years ago, Claudius Galen, a Greek physician, wrote that the lung was an instrument of voice and respiration. He thought that the purpose of respiration was to cool the heart by "the substance of the air." His concept was that breathing in (inspiration) supplied a cooling substance to the heart while breathing out (expiration) removed hot material from it. At the end of the 16th century, a Dutch scientist, Fabricius, expressed the view that the function of the lungs was to prepare air for the heart.
Until the middle of the 17th century, the lungs were thought to be a solid, compact, fleshy mass. At that time Marcello Malphigi, and Italian anatomist, and Thomas Willis, and English clinician, noted independently that the lungs were a system of canals made up of membranes, air passages, and blood vessels!
For much more information about the lung, and diseases of the lung, please visit the following areas:
- Lungs, Design and Purpose
- Asthma Center
- Chronic Cough Center
- Lung Cancer Center
- Chronic Obstructive Pulmonary Disease Center
- Smoker's Lung Pathology, Photo Essay
- Smoking and Quitting Smoking Center
Portions of the above information has been provided with the kind permission of the National Heart, Lung and Blood Institute, National Institutes of Health (www.http://www.nhlbi.nih.gov/health/public/lung/index.htm).
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Last Editorial Review: 9/30/2002