You can think of your lungs as an upside down tree, where the branches are the air tubes with ribbons of muscles surrounding them and the leaves are the balloon like structures called alveoli. As you breathe, air enters the airways and travels down to the alveoli, where oxygen enters the blood and carbon dioxide leaves the blood as a waste gas.

During an asthma attack, the muscles around the air tubes begin to tighten and the inner wall of the air tubes become swollen or inflamed such that little or no air passes through them. As a result, you begin to feel short of breath, or start coughing and wheezing. You might even feel fatigued because of the lack of oxygen reaching the blood. These are symptoms you should not ignore.