Allergen
A substance that causes inflammation in the lungs. Allergens include pollen, animal dander, dust mites and mold. Not everyone is bothered by allergens. You should try to avoid any that cause you problems. Your doctor will help you learn which ones these are.
Alveoli
Clusters of balloon-like air sacs at the ends of the airways in the lungs.
Asthma
A condition in which the lungs are very sensitive. The lungs can become inflamed and the airways get very small. This makes breathing harder.
Asthma flare-up
Also called an "asthma attack." Airways become so narrowed that you have trouble breathing. Rescue medications should be taken when this happens.
Bronchial tubes
Branching airways in the lungs. The smallest of these are called bronchioles.
Bronchiectasis
A condition in which the small airways become enlarged and cilia are destroyed. Mucus builds up and the lungs are more likely to become infected.
Bronchospasm
When the muscle surrounding the airways goes into spasm. This occurs when you have asthma.
Capillaries
Blood vessels surrounding the air sacs. Oxygen and carbon dioxide gases pass through capillaries on the way into and out of the lungs.
Carbon dioxide (CO2)
A waste gas that must be exhaled out of the body. When you can't exhale well, carbon dioxide may build up in the body and cause damage.
Chronic broncitis
A long-term condition in which the airways produce more mucus than they should. This keeps air from flowing normally.
Cilia
Tiny hairs that line the airways. These sweep mucus up and out of the lungs. Cigarette smoke can damage and paralyze cilia.
COPD (Chronic Obstructive Pulmonary Disease)
A category of diseases in which obstructions (blockages) in the lungs make breathing harder. COPD includes chronic bronchitis, emphysema, bronchiectasis, and chronic asthma.
Cystic fibrosis
An inherited condition in which thick mucus clogs the lungs.
Dyspnea
The medical word for shortness of breath, or feeling breathless.
Emphysema
A condition in which the air sacs (alveoli) are damaged and become loose and baggy. Some are destroyed. Air can't travel into and out of the lungs as easily.
Exacerbation
A period of worsened symptoms, usually due to a respiratory infection.
Gas exchange
When oxygen passes from the air sacs into the bloodstream and carbon dioxide passes from the bloodstream into the air sacs.
Inhaler
A device that delivers medication through the mouth and into the lungs. Common types of inhalers include metered dose inhalers (MDIs) and dry-powder inhalers (DPIs).
Irritants
Substances containing particles that irritate the airways, such as smoke, smog, aerosols sprays, and perfume. The lungs respond to irritants by swelling and making more mucus. People with chronic lung disease should avoid irritants when possible.
Mucus
A secretion in the lining of the airways. It traps dust, smoke and other particles that are inhaled. Mucus, along with the harmful particles, is coughed up or swallowed. This helps keep the lungs clean.
Nebulizer
A machine that changes medication into a fine mist that can be inhaled.
Oxygen (O2)
A gas your body needs in order to function.
Oxygen saturation
A measure of the amount of oxygen in the blood.
Pulmonary
Having to do with the lungs.
Pulse oximetry
A test that shows the amount of oxygen in the blood.
Respiratory
Having to do with breathing (respiration).
Restrictive lung disease
A condition in which air sacs in the lungs are scarred and become stiff. Air can't get into the scarred air sacs as easily, making it harder to take a deep breath. Also referred to as "interstitial lung disease."
Spacer
A plastic tube often used with metered dose inhalers (MDIs), which helps to ensure that most of the medication is inhaled.
Trapped air
Air that gets trapped in the air sacs and can't get out of the lungs. Trapped air flattens the diaphragm and makes breathing more difficult.
