Which of the following structures branches off secondary bronchi?

Which of the following structures branches off secondary bronchi?

• A. Primary bronchi
• B. Tertiary bronchi
• C. Alveolar sacs
• D. Alveoli

Answer: (C)

The structure that branches off secondary bronchi is correctly identified as the tertiary bronchi. Each secondary bronchus, which serves a lobe of the lung, further divides into tertiary bronchi that supply individual bronchopulmonary segments within each lobe.

The primary bronchi are the initial branches from the trachea that lead into each lung and subsequently split into secondary bronchi. Alveolar sacs and alveoli are structures involved in gas exchange but do not branch directly from bronchi; instead, they are located at the terminal end of thebronchial tree, where the airways culminate in the respiratory zone. Therefore, tertiary bronchi clearly follow the secondary bronchi in the hierarchy of the bronchial tree, making the understanding of this branching essential for studying the anatomy of the respiratory system.