In addition to their respiratory function, the lungs serve in a number of different capacities. The organs, for example, act as a soft, protective layer around the heart, helping protect it from physical harm, and are capable of filtering small clots out of the blood. Damage to the lungs can inhibit these functions as well as their more important role in the breathing process. Asthma, pneumonia, pleurisy, pulmonary hypertension, tuberculosis, respiratory syncytial virus, sarcoidosis, and cancer are just a few of the many diseases and conditions that can affect the lungs. Lung cancer and a number of other pulmonary maladies are often closely linked with smoking. More American men and women die from cancer of the lungs than any other type of cancer.

In the digital image above, a sample of rat lung tissue is presented that was labeled with the fluorophore Oregon Green 488 conjugated to wheat germ agglutinin, a fluorescent lectin that selectively binds to sialic acid residues. Wheat germ agglutinin conjugates are often used as probes for the Golgi network in mammalian tissues and cells. The sample was also stained with Alexa Fluor 568 conjugated to phalloidin and Hoechst 33342, which target the cytoskeletal filamentous actin network and nuclear DNA, respectively. Images were recorded in grayscale with a 12-bit digital camera coupled to a Nikon Eclipse 80i microscope equipped with bandpass emission fluorescence filter optical blocks. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.