How many tertiary (segmental) bronchi are there in the left lung?

The left lung contains a total of eight tertiary (segmental) bronchi. This is because the left lung is divided into two lobes—the upper and the lower lobes. The upper lobe has four bronchopulmonary segments, while the lower lobe has five segments. Each segment corresponds to its own tertiary bronchus, resulting in the total of eight bronchi in the left lung.

This division is important as each segment can be independently ventilated and supplied with blood. Understanding the segmentation of the lungs is crucial for procedures such as surgery or for diagnosing and treating lung diseases.