Phlegm is a form of respiratory mucus produced by the lungs. The airways between the larynx and the respiratory bronchioles are lined by columnar epithelium over which an airway surface liquid (ASL) ...

Mucus is more than just the sticky snot that comes from your nose. This protein-rich goop is found in many other organs, including the lungs and intestines, where it forms a protective layer that ...

Being sick with a cold or other congestion-causing illness comes with a variety of symptoms, but a particularly annoying one is the buildup of mucus in your nasal passages and throat. In addition to ...