AsthmaAsthma is ussually seen as a condition whose symptoms can be adequately controlled with the right medicines. Researchers point out that it is an intermittent disorder,characterized by temporary bouts of inflammation of the airways,which lead to typi

Asthma

Asthma is ussually seen as a condition whose symptoms can be adequately controlled with the right medicines. Researchers point out that it is an intermittent disorder,characterized by temporary bouts of inflammation of the airways,which lead to typical symptoms such as wheezing,coughing and shortness of breath;after each episode(often known as an attack),symptoms subside and the airways return to normal.

Asthmatics tend to be susceptible to certain triggers in the environment. These include but are not restricted to animal fur,pollen, cigarette smoke,house dust mites and perfumes. Attacks can also be brought on by exercise,emotional sters or a variety of other factors including respiratory infections such as the common cold.

During an episode of asthma, the bronchial tubes and the smaller tubes dividing off from these,known as bronchioles,become narrow or blocked and as a result air can't get in or out of the lungs easily. There are two basic causes behind bronchial narrowing: either the bronchi and bronchioles are squeezed by muscles wrapped arround them rather like elastic bands,or they become blocked by mucus and swelling inside the tubes themselves.When the bronchi are constricted ,the condition is called bronchoconstriction. Occasional squeezing of the bronchi is normal, but in asthma sufferers these muscles may react too sensitively to environmental triggers. It is also a normal function of the bronchial tubes to produce mucus and,in concert with tiny hairs called cilia, to trap inhaled irritants and remove them from the body,thus protecting the lungs. But some asthmatics produce an overabundance of mucus,and this results in blocked airways and consequent asthmatic symptoms.

Summarize the points made in the lecture you heard,explaining how they cast doubt on the points made in the reading.