Final answer:
Gas exchange does not occur in the bronchioles; it occurs in the alveoli. Bronchioles guide air to the alveoli but are not directly involved in the exchange of oxygen and carbon dioxide.
Step-by-step explanation:
Gas exchange occurs in all of the following locations except Bronchioles. The alveoli are the primary sites for gas exchange, where oxygen is absorbed into the blood and carbon dioxide is released from the blood. Alveolar ducts connect to alveolar sacs, which in turn are surrounded by numerous alveoli where this gas exchange takes place. Air travels from the pharynx to the trachea, then to the bronchi, and subsequently to the bronchioles.
While the bronchioles play a crucial role in the respiratory system by guiding air to the alveoli, they are not themselves sites of gas exchange. The conducting zone, comprising the bronchioles, serves primarily to direct airflow. In contrast, the alveoli which are part of the respiratory zone are where actual gas exchange occurs due to simple diffusion across their thin one-cell-thick membranes that are in direct contact with blood capillaries.