When you have asthma, airway inflammation and swelling cause the airways to be overly sensitive or “twitchy.” This twitchiness causes the narrowing and blockage of the airways. As the inflammation increases, the airways become more sensitive and overactive.
During an asthma episode, the mucus-producing cells within the airway increase their output and mucus plugs the airway. The combination of airway narrowing, mucus plugging, and airway inflammation can block portions of the airway entirely. Air becomes trapped in the alveoli (air sacs at the end of the bronchioles). This trapped air cannot provide for the proper exchange of oxygen and carbon dioxide. Trapped air leads to hypoxia (low oxygen content) in the body.
This is what a normal pair of lungs looks like >>
Air trying to pass through the narrowed tubes filled with mucus may produce wheezing. Wheezing is a high-pitched whistling sound, often associated with asthma. Other symptoms of asthma include a persistent cough, chest tightness, shortness of breath, or decreased endurance. Coughing is usually the most common and may be the only symptom.
Severe effects of asthma may include loss of elasticity of the lungs due to air trapping and low oxygen; this is called “airway remodeling”. Children may not grow as well due to long-term trapped air and low oxygen content in the body, and asthma may cause irritability and fatigue for all ages.