In Emphysema the tiny, delicate air sacs (alveoli) in your lungs are damaged. The walls of the damaged air sacs become stretched out and your lungs actually get bigger, making it harder to move your air in and out. Old air gets trapped inside the alveoli so there is little or no room for new air to go. In emphysema it is harder to get oxygen in and carbon dioxide (the waste product of your breathing) out.
Chronic bronchitis is an inflammation of the breathing tubes (bronchial airways) inside your lungs. Tiny hair-like structures (cilia) line your airways and sweep mucus up, keeping your airways clean. When cilia are damaged, they can’t do this, and it becomes harder for you to cough up mucus. This can make your airways swollen and clogged. These changes limit airflow in and out of your lungs, making it hard to breathe.
Refractory (non-reversible) asthma is a type of asthma that does not respond to usual asthma medications. In an asthma attack, bronchial airways tighten up and swell. Medications can usually reverse this, opening up the airways and returning them to how they were before the asthma attack. In refractory asthma, medications cannot reverse the tightening and swelling of the airways.