In a person with asthma, the inside walls of the airways, known as bronchial tubes, become swollen or inflamed. This swelling or inflammation. Bronchial asthma is a medical condition which causes the airway path of the lungs to swell and narrow. Due to this swelling, the air path produces excess mucus. Bronchial asthma is a chronic, inflammatory disease of the respiratory tract, which is characterized by bronchial hyperreactivity and respiratory obstruction.