Chronic Obstructive Pulmonary Disease (COPD) (cont.)
George Schiffman, MD, FCCP
Dr. Schiffman received his B.S. degree with High Honors in biology from Hobart College in 1976. He then moved to Chicago where he studied biochemistry at the University of Illinois, Chicago Circle. He attended Rush Medical College where he received his M.D. degree in 1982 and was elected to the Alpha Omega Alpha Medical Honor Society. He completed his Internal Medicine internship and residency at the University of California, Irvine.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Chronic obstructive pulmonary disease facts
- What is COPD?
- How does the normal lung work?
- What is chronic bronchitis?
- What is emphysema?
- What is chronic asthma?
- What is bronchiectasis?
- What causes COPD?
- What are the symptoms of COPD?
- How is COPD diagnosed?
- What treatment is available for COPD?
- Quitting cigarette smoking
- COPD Medications
- Bronchodilators
- Beta-agonists
- Anti-cholinergic agents
- Methylxanthines
- Corticosteroids
- Breo Ellipta
- Treatment of Alpha-1 antitrypsin deficiency
- What is the role of oxygen as therapy in COPD?
- What else is available for treating COPD?
- Future directions in COPD
- COPD (Chronic Obstructive Pulmonary Disease) FAQs
- Find a local Pulmonologist in your town
How does the normal lung work?
The lung is the organ for gas exchange; it transfers oxygen from the air into the blood and carbon dioxide (a waste product of the body) from the blood into the air. To accomplish gas exchange the lung has two components; airways and alveoli. The airways are branching, tubular passages like the branches of a tree that allow air to move in and out of the lungs. The wider segments of the airways are the trachea and the two bronchi (going to either the right or left lung). The smaller segments are called bronchioles. At the ends of the bronchioles are the alveoli, thin-walled sacs. (The airways and alveoli can be conceptualized as bunches of grapes with the airways analogous to the stems and the alveoli analogous to the grapes.) Small blood vessels (capillaries) run in the walls of the alveoli, and it is across the thin walls of the alveoli where gas exchange between air and blood takes place.
Breathing involves inspiration followed by exhalation. During inspiration, muscles of the diaphragm and the rib cage contract and expand the size of the chest (as well as the airways and alveoli) causing negative pressure within the airways and alveoli. As a result, air is sucked through the airways and into the alveoli and the chest wall is enlarged. During exhalation, the same muscles relax and the chest wall springs back to its resting positions, shrinking the chest and creating positive pressure within the airways and alveoli. As a result, air is expelled from the lungs.
The walls of the bronchioles are weak and have a tendency to collapse, especially while exhaling. Normally, the bronchioles are kept open by the elasticity of the lung. Elasticity of the lung is supplied by elastic fibers which surround the airways and line the walls of the alveoli. When lung tissue is destroyed, as it is in patients with COPD who have emphysema, there is loss of elasticity and the bronchioles can collapse and obstruct the flow of air. Normal lung tissues look a lot like a normal sponge. Emphysema often looks like an old sponge with large irregular holes and loss of the spring and elasticity.
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