How does the trachea protect lungs from pathogens?

The trachea defends the lungs through a multi-layered protection system. First, the mucociliary escalator traps pathogens in sticky mucus produced by goblet cells. Cilia then sweep this mucus upward to the throat, where it’s swallowed or expelled.

Second, the epithelial cells secrete antimicrobial peptides and enzymes like lysozyme that destroy bacteria. Third, immune cells such as macrophages and dendritic cells patrol beneath the tracheal lining, detecting and responding to invading microbes.

The trachea’s shape and cartilage rings also maintain open airflow, preventing mucus buildup that could harbor pathogens. When pathogens attempt to infect, reflexes like coughing and sneezing act as mechanical defenses, expelling irritants.

Together, these mechanisms keep harmful substances out of the delicate alveoli, where gas exchange occurs. In short, the trachea is the body’s first respiratory defense checkpoint, filtering, neutralizing, and removing potential threats before they reach the lungs.