Final answer:
Each bronchopulmonary segment is divided into many lobules, with bronchioles branching within these lobules leading to alveoli for gas exchange.
Step-by-step explanation:
Each bronchopulmonary segment is divided into many lobules. When the tertiary bronchi branch into smaller tubes, these are known as bronchioles, which further divide until they become the tiny terminal bronchioles. Each bronchopulmonary segment receives air from its own tertiary bronchus and is supplied with blood by its own artery. Within the lobules, the bronchioles branch into multiple smaller passageways, leading to structures of gas exchange called alveolar ducts and eventually to alveolar sacs. An interlobular septum, which is made of connective tissue, separates the lobules.