Where does expired air go after the bronchi?

After passing through the bronchi, expired air moves into the bronchioles, which are smaller air passages within the lungs. From the bronchioles, the air then travels to the alveoli, where gas exchange occurs. Once the oxygen in the air is depleted and carbon dioxide is present, the expired air travels back through the bronchioles and bronchi, eventually exiting the body through the trachea and mouth or nose.