Asthma: A Lung Disease

(Mayo Clinic, 2014).
             Pathogenesis of Asthma.
             While asthma is considered an inflammatory disorder of the conducting airways, it is becoming increasingly apparent that the disease is heterogeneous with respect to immunopathology, clinical phenotypes, response to therapies, and natural history. Once considered purely an allergic disorder dominated by Th2-type lymphocytes, IgE, mast cells, eosinophils, macrophages, and cytokines, the disease also involves local epithelial, mesenchymal, vascular and neurologic events that are involved in directing the Th2 phenotype to the lung and through aberrant injury-repair mechanisms to remodeling of the airway wall. Structural cells provide the necessary "soil" upon which the "seeds" of the inflammatory response are able to take root and maintain a chronic phenotype and upon which are superimposed acute and subacute episodes usually driven by environmental factors such as exposure to allergens, microorganisms, pollutants or caused by inadequate anti-inflammatory treatment. Greater consideration of additional immunologic and inflammatory pathways are revealing new ways of intervening in the prevention and treatment of the disease. Thus increased focus on environmental factors beyond allergic exposure (such as virus infection, air pollution, and diet) are identifying targets in structural as well as immune and inflammatory cells at which to direct new interventions. (PubMed, 2008) .
             Normal Functioning of the Respiratory System.
             The respiratory system is the group of tissues and organs in your body that enable you to breathe. This system includes your airways, your lungs and the blood vessels and muscles attached to them that work together so you can breathe. The respiratory system's primary function is to supply oxygen to all the parts of your body. It accomplishes this through breathing: inhaling oxygen-rich air and exhaling air filled with carbon dioxide, which is a waste gas.