Introduction

Emphysema (one of the diseases of chronic obstructive pulmonary disease,COPD) is a progressive lung disease in which the delicate air sacs called alveoli in the lungs become irreversibly damaged, which results in shortness of breath. Alveoli in lungs of people with emphysema are larger, fewer and over-inflated with gaping holes in their inner wall.  

Reduced number of alveoli affects the lung’s ability to expel air

The reduction in surface area of the lung limits the amount of oxygen in a patient’s bloodstream, while the enlarged alveoli cannot maintain their functional shape upon exhalation. Unlike the lungs of a healthy individual, the alveoli in a patient with emphysema lose elasticity, and are unable to expand and recoil efficiently to remove air, which leads to the expansion and rupture of the alveoli.

                                Illustration of healthy and damaged alveoli

A patient with emphysema would have the difficulty to exhale since the alveoli cannot deflate completely. Hence, the next breath is started with more air in the lungs. The trapped air occupies space, so the alveoli are unable to fill with enough fresh air to supply the body with needed oxygen. Over time, the lungs slowly enlarge, and breathing requires more effort. As a result, a person with emphysema may experience breathlessness, even if they are at rest.

References

• http://en.wikipedia.org/wiki/Emphysema

• http://medical-dictionary.thefreedictionary.com/alveolar+emphysema