Blockage of which structure prevents airflow into and out of the lungs?

Airflow into and out of the lungs is primarily facilitated by the trachea, which serves as the main airway connecting the throat (pharynx and larynx) to the bronchi that lead into each lung. If the trachea becomes blocked, airflow will be obstructed, significantly impairing the ability to breathe. This blockage can be caused by various factors, such as foreign objects, swelling, or other medical conditions.

While the bronchi also play a vital role in conducting air into the lungs, they are downstream from the trachea; thus, blockage of the trachea has a more immediate and severe impact on overall airflow. The diaphragm, a muscle situated below the lungs, facilitates breathing through its contraction and relaxation, but does not directly govern airflow pathways. The alveoli are tiny air sacs where gas exchange occurs; therefore, their blockage affects oxygen and carbon dioxide exchange rather than directly obstructing airflow.