Certified Respiratory Therapist Exam 2025 – 400 Free Practice Questions to Pass the Exam

Gas exchange occurs in the alveoli, which are tiny, thin-walled air sacs located at the end of the bronchial tubes within the lungs. These structures are specifically designed for the efficient exchange of oxygen and carbon dioxide between the air we breathe and the bloodstream.

The alveoli are surrounded by a network of capillaries, allowing oxygen from the inhaled air to diffuse through the alveolar walls into the blood while carbon dioxide diffuses from the blood into the alveoli to be exhaled. This exchange is critical for maintaining the body's oxygen levels and removing carbon dioxide, a waste product of metabolism.

The bronchi and trachea are part of the airway that conducts air to the alveoli but do not participate in gas exchange themselves. They serve primarily as passageways for airflow, not sites for gas diffusion. The lungs, as a larger anatomical structure, contain both the bronchi and the alveoli, but the actual exchange of gases specifically takes place within the alveoli, where the intimate contact between air and blood occurs.