Bronchial asthma - a disease in which the airways are narrowed, because of increased sensitivity to some factors causing inflammation, narrowing of the airways is reversible.
The disease is becoming more common. From 1982 to 1992 the number of patients with asthma increased by 42%, mortality - by 35%. The disease occurs more and more difficult, more often requires hospitalization. Bronchial asthma affects about 10 million Americans. In Russia the incidence of bronchial asthma is also increasing and is at least 5-6% of the adult population.
How airways become narrow
During an attack of bronchial asthma bronchial smooth muscle spasms and tissue lining the airways, swelling due to inflammation and produce excess mucus, narrowing the airways.
1. Normal airway
2. Spasm respiratory
3. Edema of the mucous membrane
4. Mucous plugs
Causes
In bronchial asthma, the airways narrow in response to the impact of factors that the respiratory tract of healthy people are not affected. Narrowing can be caused by pollen, house dust mites, animal hair, smoke, cold air and physical exercise. During the attack of bronchial smooth muscle spasms and tissue lining the airways, swelling due to inflammation and produce excess mucus. The diameter of the airways is decreased (a condition called bronchospasm), and the man takes more effort to inhale and exhale.
Some cells in the respiratory tract, especially the so-called mast cells, play a direct role in the development of narrowing of the airways. Mast cells isolated bronchial histamine and leukotrienes - substances that cause contraction of the smooth muscle, increasing the output of mucus and the migration of certain types of leukocytes. Mast cells can produce these substances in response to a foreign agent (allergen), such as pollen, house dust mites or animal fur. However, bronchial asthma occurs, and in quite severe, many people do not suffer from allergies. When asthma patients perform physical work or inhale cold air, he had such a reaction occurs. Tension and anxiety can also provoke the selection mast cells release histamine and leukotrienes. Eozinofils - other type of cells that appear in the airways of people with asthma - also emit substances, including leukotrienes and some others that contribute to a narrowing of the airways.
