Final answer:
The laryngotracheal bud, which forms from the lung bud during week 4 of embryonic development, differentiates into the trachea and bronchial buds. These bronchial buds further develop into the bronchi, bronchial tree, and respiratory bronchioles, comprising the major airway structures of the lungs.
Step-by-step explanation:
The structures that develop from the laryngotracheal bud are crucial to the respiratory system. During embryonic development around week 4, the laryngotracheal bud forms from the lung bud. Initially, it comprises a tracheal end and distal bulbous bronchial buds. Eventually, the part of the laryngotracheal bud nearest to the pharynx differentiates into the trachea. Simultaneously, the distal end bulges and branches out to form bronchial buds. These bronchial buds are the primordial structures that give rise to the lungs' bronchi and all other lower respiratory system components including the bronchial tree and respiratory bronchioles.
By week 7 to 16, these bronchial buds continue to develop and branch extensively until all segmental bronchi are formed. Around week 16, the respiratory bronchioles also develop, denoting the formation of all major airway structures in the lungs. The primary bronchi enter the lungs at the hilum and branch into a bronchial tree, which functions as a passageway for air to enter and leave the lungs.