Bronchitis is the swelling of the bronchial tubes … the air passages between the nose and the lungs. It occurs when the lining of the bronchial tubes becomes inflamed or infected.
Some doctors also define bronchitis as an inflammation of the mucous membranes of the bronchi (the larger and medium-sized airways that carry airflow from the trachea into the more distal parts of the lung parenchyma).
In otherwards it is a respiratory disease in which the mucous membranes of the bronchial passages in the lungs become so inflamed. When the irritated membrane swells and grows thicker, it narrows or shuts off the airways in the lungs, resulting in coughing spells accompanied by thick phlegm and breathlessness.
Bronchitis occurs in two forms ie acute (lasting less than 6 weeks) and chronic (reoccurring frequently for more than two years).
People suffering from bronchitis breathe less air and oxygen into their lungs. And they also have heavy mucus or phlegm forming in the airways.
Bronchitis may be acute or chronic: Acute bronchitis many times is caused by viruses, especially those that cause colds and influenza.
Antibiotics don’t kill viruses, so this type of medication isn’t useful in most cases of bronchitis.