This site states this specific description directly: MedlinePlus has a plain-language overview of lung diseases.
Worth reading this as this site deliberately pointing toward an accessible, non-technical government resource — useful if you're trying to understand a symptom without wading through clinical terminology.
This site places this link directly alongside its own "if breathing problems are worrying you, see a doctor" instruction — worth reading both together as a practical next step, not just a citation.
Backed by a 60-day money-back guarantee.
See The Current BreathiZen Offer