What does the bronchus produce?

The bronchus, which is a major air passage in the respiratory system, primarily functions to conduct air to and from the lungs. It produces mucus through its epithelial lining, which helps trap dust, pathogens, and other particles, keeping the airways clear and protecting the lungs. Additionally, the bronchial walls contain smooth muscle and cartilage, aiding in the regulation of air flow and maintaining airway structure.