BRIAN EVANS / SCIENCE PHOTO LIBRARY BRIAN EVANS / SCIENCE PHOTO LIBRARY
Asthma. Artwork of the narrowing of airways (bronchioles) in the lungs caused by asthma. Normally, oxygen is transported into the blood stream via the thin-walled alveoli (bottom left). A trigger such as an allergen can bring on an asthma attack. The airways become inflamed (cutaway section) and produce excess phlegm (not shown), making it difficult to get oxygen into the alveoli. Treatment is usually in the form of an inhaler containing bronchodilator drugs to widen the airways and steroid drugs to reduce the inflammation. Asthma is a chronic disease that usually arises in childhood and improves as the patient matures.
Model release not required. Property release not required.