My Pink Spongy Lungs...

The lungs are certainly one of the coolest organs to look at in lab class due to their light, fluffy feeling and their ability to expand to large volumes and quickly recoil... amazing! The above image shows a normal lung before and after inflation. Part of the ability of the lungs to expand and recoil is due to the extracellular matrix of the lung tissue which contains collagen and lots of elastin protein fibers. This gives the lungs their ability to recoil after inhalation so that air is exhaled properly. The videos below show this in action...





Smoking is a health hazard for many reasons such as heart disease and cancer, but smoking also can damage the physical structure of the lung. Cigarette smoking leads to neutrophil activation and retention in the lung tissues. Cigarette smoking induces macrophages to release neutrophil chemotactic factors and elastases, thus unleashing tissue destruction. A number of neutrophil-derived and macrophage-derived enzymes known as proteinases and elastases (ie, proteolytic enzymes) can destroy various components of the extracellular matrix of the lung (e.g., elastin fibers) and cause emphysema (see eMedicine). The tissue integrity of the tiniest airways (like the alveoli and respiratory bronchioles) is destroyed over time and normal elasticity is lost. There is also destruction of the aveolar capillaries which impairs gas exchange in the lung. All of this reduces the ability of the lungs to function and this is especially noticeable when patients with emphysema are asked to expire after maximal inhalation. It takes them longer to expire air out of their lungs since exhalation requires the inherent elasticity of the lung tissues, which they have lost with emphysema.



~~BIO26~~