1. How Smoking Affects Your Looks & Life Slideshow
2. Tips to Quit Smoking Slideshow
3. Take the Quiz on Smoking

Medical Author:

Michael C. Fishbein, MD

Michael C. Fishbein, MD

Dr. Fishbein received his undergraduate and medical degrees from the University of Illinois. He completed a residency in anatomic and clinical pathology at Harbor General Hospital/UCLA Medical Center. He is board certified in anatomic and clinical pathology.

View Full Profile

Medical Editor:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

View Full Profile

In this Article

• Smoker's lung introduction
• What is the structure of the normal lung?
• What processes determine normal function of the lung?
• What are the abnormalities (diseases) in smoker's lung?
• What happens to the lung in emphysema?
• How does emphysema come about?
• Why does smoker's lung look black?
• What happens to the airways in chronic bronchitis?
• Are smokers with COPD predisposed to developing pneumonia?
• What about lung cancer in smokers?
• Are any of the pulmonary consequences of smoking reversible?
• From what do smokers die?
• Patient Comments: Smokers' Lung - COPD
• Smoker's Lung: Pathology Photo Essay Index

In emphysema, the walls of the air sacs (alveolar septae) are destroyed. Consequently, the individual air spaces (alveoli) become larger but irregular and decreased in number. These larger spaces are less efficient than normal sized alveoli for gas exchange. Thus, emphysema impairs diffusion of oxygen and carbon dioxide (gas exchange). The more extensive the emphysema, the poorer the gas exchange becomes. Also, in emphysema, the capillaries are destroyed with the rest of the alveolar wall. As a result, emphysema also disrupts the normal blood supply. Figure 4 contrasts the nasty appearance of a smoker's emphysematous lung with a normal lung.

Figure 4: SMOKER'S AND NON-SMOKER'S LUNGS
(Roll mouse over each image to see which is which.)

Emphysema usually starts in the upper lobes of the lung and, as depicted in this photo, is more severe in the upper lobes for complex reasons. That is, the abnormal (enlarged and irregular) air sacs (alveoli) are more prominent in the upper lobes. (The blood vessels in the lungs should not be mistaken for the abnormal air sacs.)

In someone with severe emphysema, the entire chest actually can enlarge. What probably happens is that the patient's extra (compensatory) efforts to suck in as much air as possible (to increase ventilation) contribute to enlarging the lungs and the chest. Thus, a person with severe emphysema often develops what has been described as a barrel-chest.