Asthma :: essays research papers fc

Asthma is a respiratorydisorder marked by breathing bar caused bytemporary narrowing of the bronchi, the airways branched from the trachea to the lungs. Attacksusually are brought on by allergic response toANTIGENS such as grass and tree pollens, moldspores, fungi, animal dander, and certain(a) foods but may also be caused by chemical irritants in theatmosphere or by infections of the respiratorytract. Susceptibility to an asthma oncoming is basedon hyperactivity of the bronchial muscles, whichconstrict on exposure to integrity or another of theseagents. Episodes of asthma vary widely in hard knocksand may last from a few minutes to several days.They may begin at any age but usually move on inchildhood. In children, asthma often is associatedwith eczema, a skin release that may reflectthe tendency of the child to bumphypersensitivity reactions. The attacks usually plump slight frequent and less severe over theyears and go forth in about half of all affectedchildren befo re adulthood. In one form of asthma,called intrinsic asthma, however, the attacks constrain less frequent and less severe, butrecovery between them is less complete. Thebronchi in such patients become chronicallynarrowed, causing a progressive loss of capacityfor visible exertion. The prevalence of asthma isonly about 1 or 2 percent worldwide but variesgreatly from country to country. In the unifyStates, asthma affects about 6.9 percent ofchildren. Typically, an asthma attack begins withinminutes after exposure to a triggering agent.Symptoms include a sensation of tightfistedness in thechest, coughing and wheezing, and difficulty inbreathing. Persons having attacks usually find it more(prenominal) difficult to exhale then inhale, which causesoverinflation of the chest and impaired lungfunctions. The breathing difficulty is alleviatedsomewhat by leaning forward and supporting the tree trunk with the arms on some object. Attacks thatlast several hours or more, compensate several d ays,despite treatment are called status asthmaticus.Patients with this condition discipline a rapid pulseas the heart attempts to compensate for the wishing ofoxygen in the blood by beating faster. They alsodevelop signs of exhaustion and dehydration. On along-term basis, asthma usually is managed bydetermining the agent responsible for the attacksso that the patient can negate it. When avoidance ofallergens is not feasible, patients can sometimes be