Final answer:
The Pseudoglandular period of lung development, which occurs from weeks 6 to 16, sees the formation of bronchial buds, segmental bronchi, and respiratory bronchioles, all critical structures involved in the airway.
Step-by-step explanation:
During the Pseudoglandular period, which is from the 6th to the 16th week of fetal development, several critical structures of the lungs are formed. This stage is characterized by the branching of bronchial buds into segmental bronchi, which takes place until all segmental bronchi have been established. By the 13th week, the lumens of the bronchi expand in diameter.
By the end of the Pseudoglandular period, around the 16th week, the respiratory bronchioles have formed, marking the presence of all major lung structures involved in the airway and preparing the fetus for subsequent phases of lung development that will continue to adulthood.