Kaplan Nursing Entrance Practice Exam

What are alveoli primarily responsible for in the respiratory system?

1. Filtering air particles

2. Transporting air

3. Gas exchange

4. Vocalization

The correct answer is: Gas exchange

The primary function of alveoli in the respiratory system is gas exchange. Alveoli are tiny air sacs located at the end of the bronchioles in the lungs, and they provide a large surface area for the exchange of oxygen and carbon dioxide between the air and the blood. When air reaches the alveoli, oxygen from the air diffuses across the thin walls of these sacs and into the bloodstream, where it is transported to cells throughout the body. Concurrently, carbon dioxide, which is a waste product of metabolism, diffuses from the blood into the alveoli to be exhaled. This process is essential for maintaining the body’s acid-base balance and ensuring that tissues receive the oxygen they need for cellular functions. While filtering air particles, transporting air, and vocalization are important aspects of the respiratory system, they do not occur within the alveoli. Filtering air particles is primarily carried out by structures in the nasal passages and upper airways. Transporting air is associated with the bronchi and bronchioles, which direct air to the alveoli. Vocalization involves the larynx and vocal cords, not the alveoli. Thus, the correct answer highlights the critical role of alveoli specifically in gas exchange, which is vital