Biology STAAR (State of Texas Assessments of Academic Readiness) Practice Test

What is the function of the trachea in the respiratory system?

1. Filtering the blood

2. Transporting air to the lungs

3. Exchanging gases

4. Regulating lung capacity

The correct answer is: Transporting air to the lungs

The trachea, commonly known as the windpipe, serves a vital role in the respiratory system by transporting air from the larynx down to the lungs. This structure is a tubular passageway lined with ciliated mucosa that not only allows air to flow but also helps to filter, warm, and moisten the air as it travels. The trachea is integral in maintaining the pathway for oxygen to enter the lungs and for carbon dioxide to exit, making it essential for efficient respiration. In the context of the other options, filtering the blood is a function associated with the kidneys, not the trachea. Gas exchange occurs in the alveoli of the lungs, not in the trachea itself. Additionally, regulating lung capacity pertains to the diaphragm and other muscles involved in breathing, rather than the tracheal function. Thus, the primary role of the trachea is indeed transporting air to the lungs.