What is asthma characterized by in the respiratory system?

• A. Inflammation and narrowing of the airways
• B. Infection of the alveoli
• C. Formation of excess pleural fluid
• D. Overexpansion of the lungs

Answer: (A)

Asthma is a chronic inflammatory disease of the airways. Inflammation causes swelling of the airway walls, increased mucus production, and tightening of the smooth muscle around the bronchi, all of which narrow the airways. This combination leads to episodic airflow obstruction, producing symptoms like wheezing, coughing, and shortness of breath, and it is typically reversible with treatment or spontaneously. The other options describe different problems: infection of the alveoli would be pneumonia; excess pleural fluid is a pleural effusion; overexpansion of the lungs relates to conditions with air trapping such as some forms of emphysema, not the hallmark feature of asthma.