What is the term for the portion of the lung supplied by a tertiary bronchus?

The term for the portion of the lung supplied by a tertiary bronchus is the bronchopulmonary segment. Each bronchopulmonary segment is an anatomical and functional unit of the lung, with each segment receiving air from its own bronchus and serving as a discrete area for gas exchange. There are typically 10 bronchopulmonary segments in the right lung and 8 to 10 in the left, each separated by connective tissue, which provides a degree of independence in terms of function and disease processes.

The other terms refer to different anatomical structures: a lobar segment refers to portions of the lung supplied by secondary (lobar) bronchi, the terminal lobule is a smaller unit that includes the respiratory bronchioles and alveoli, and an alveolar sac is a cluster of alveoli where gas exchange occurs. Understanding these distinctions aids in grasping the organization and function of the pulmonary system.