An allergy refers to a misguided reaction by our immune system in response to bodily contact with certain foreign substances. When these allergens come in contact with the body, it causes the immune system to develop an allergic reaction in people who are allergic to it. It is estimated that 50 million North Americans are affected by allergic conditions. The parts of the body that are prone to react to allergies include the eyes, nose, lungs, skin, and stomach. Common allergic disorders include hay fever, asthma, allergic eyes, allergic eczema, hives, and allergic shock.
The lungs are primarily responsible for the exchange of oxygen and carbon dioxide between the air we breathe and the blood. Eliminating carbon dioxide from the blood is important, because as it builds up in the blood, headaches, drowsiness, coma, and eventually death may occur. The air we breathe in (inhalation) is warmed, humidified, and cleaned by the nose and the lungs.