When a person breathes, air travels down the windpipe through a series of tubes called bronchi, which gradually get smaller. At the end of these tubes are bunches of air sacs called alveoli.
In healthy lungs, the alveoli fill up with air and pass oxygen through to the blood vessels that run along them. At the same time, the blood passes carbon dioxide back to the alveoli for exhalation.
In obstructive lung disease, less air flows in and out of the alveoli and fewer gas exchanges can happen. This can happen for many reasons, depending on which type of obstructive lung disease a person has.
Types of obstructive lung disease include:
chronic obstructive pulmonary disease (COPD) emphysema asthma cystic fibrosis