what does a serevent inhaler do for asthma?

I would like to say that my life is perfect, but it is actually far from that. I suffer from asthma for a long time now and I had several severe episodes, but, fortunately, they ended well. I am taking my medications regularly, but last time I went to a doctor, he prescribed me with some different inhaler (serevent) and I would like to know what does a serevent inhaler do for the asthma?

This is a so called selective beta 2 agonist, it has a prolonged period of effect, for about 12 hours. The basic rule is that it prevents constriction of bronchi (which is the basic symptoms in asthma attack). The effect is very strong and positive with asthma. In the process, this drug is accumulated in the bronchi, which makes the period of effect much longer.