Final answer:
The bronchial tree, which carries air between the trachea and the lungs, comprises the primary bronchi that subdivide into secondary and tertiary bronchi, and then into smaller bronchioles, ending in terminal bronchioles connected to alveoli. This branching system is supported by cartilage and smooth muscle and features a lining that traps and removes debris.
Step-by-step explanation:
From the trachea, air moves into the primary bronchi, which are the main passageways into the lungs. The primary bronchi further subdivide into secondary and tertiary bronchi. These then branch into smaller tubes called bronchioles. The bronchial tree is the collective term for these branches.
The bronchial tree carries air between the trachea and the lungs and ensures that inhaled air reaches the alveoli for gas exchange. The branching continues until reaching the smallest unit, the terminal bronchioles, which lead to the gas exchange structures.
Each bronchus and subsequent branches are supported by cartilage, which prevents them from collapsing, while the bronchioles rely more on elastic fibers and smooth muscle. The walls of the bronchi and bronchioles are lined with ciliated columnar epithelium and goblet cells that trap debris and pathogens, with cilia helping to move this mucus out of the respiratory system.