What is the term for the substance that is coughed up from the bronchi?

The term for the substance that is coughed up from the bronchi is "sputum." Sputum refers specifically to the mixture of saliva and mucus that is expelled from the respiratory tract during coughing. It often contains cellular debris, pathogens, and other substances, making it a useful diagnostic tool for evaluating respiratory illnesses.

While "phlegm," "mucus," and "saliva" are related terms, they do not accurately capture the definition of the substance in this context. Phlegm is a type of mucus but is often considered to refer to the thick, viscous secretions produced in the respiratory tract specifically during illness. Mucus is a general term for the slippery secretion produced by mucous membranes and does not specify its source or context regarding the bronchial system. Saliva, produced in the mouth, is not related to the respiratory system in the same context. Thus, sputum is the most precise term for the substance discharged from the bronchi during coughing.