Asthma has two components: constriction and inflammation of the air tubes. Using a tree as a metaphor, one can think of the lung air tubes as branches in a tree. The trunk of the tree carries the air in and then the air moves out to smaller branches and the twigs in the tree. The smallest branches, are called “bronchioles” and those have a band of muscle around them – that’s smooth muscle and that can constrict.
Smooth muscle can act like a rubber band around a straw. If that rubber band squeezes then the straw gets tighter on the inside and it’s more difficult for air to move in and out of the straw. This is essentially what happens during an asthma attack and the person affected feels as though he can’t get enough air in or out. The good news is that there are medicines and technologies that are really helpful in reversing constricting.
The other component of asthma is inflammation, which may be easier to understand as “swelling”. The straw in the example represents a bronchiole, which is the tiny tube carrying the air. Imagine it swelling. If it swells so much that the inside diameter of the straw actually gets really tight, then it’s possible to have trouble moving air in and out. And that also happens with asthma.
Different people have different amounts of inflammation or different amounts of constriction. Since this happens in tubes called the “bronchioles”, medical professionals refer to these issues as “bronchoconstriction” and “bronchio-inflammation”. There are medicines that are used routinely in asthma to improve both. There are also medical technologies that are used when the medicines are not helpful.