How do diseases like asthma affect the airways and gas exchange?

Asthma affects the airways and gas exchange by causing inflammation and narrowing of the bronchial tubes, reducing airflow.

Asthma is a chronic disease that affects the respiratory system, specifically the bronchial tubes which are the airways that carry air in and out of the lungs. The bronchial tubes of individuals with asthma are inflamed and swollen, which makes them highly sensitive to various triggers such as allergens, cold air, exercise, or stress. When exposed to these triggers, the bronchial tubes constrict and produce excess mucus, leading to further narrowing of the airways. This results in difficulty in breathing, wheezing, coughing, and shortness of breath, which are the typical symptoms of an asthma attack.

The narrowing of the airways due to asthma significantly affects the process of gas exchange in the lungs. Gas exchange is the process by which oxygen is absorbed from the air into the bloodstream and carbon dioxide is expelled from the bloodstream into the air. This process takes place in the alveoli, tiny air sacs in the lungs where the walls are thin enough to allow gases to pass through. When the bronchial tubes are narrowed, the amount of air reaching the alveoli is reduced, which means less oxygen is available for absorption into the bloodstream. At the same time, the expulsion of carbon dioxide from the bloodstream into the air is hindered, leading to a build-up of this waste gas in the body.

Furthermore, the inflammation and excess mucus production associated with asthma can also damage the alveoli, further impairing gas exchange. The mucus can block the airways, preventing air from reaching the alveoli, while the inflammation can thicken the walls of the alveoli, making it harder for gases to pass through. This can lead to hypoxia, a condition where there is insufficient oxygen in the body to meet its needs, and hypercapnia, a condition characterised by excessive carbon dioxide in the bloodstream. Both conditions can have serious health consequences if not managed properly.