What are the three basic defense mechanisms of the respiratory system?

The three basic defense mechanisms of the respiratory system involve essential processes that protect the lungs and airways from harmful substances, pathogens, and irritants. The correct choice outlines these mechanisms accurately.

First, the respiratory system filters, warms, and humidifies the air that is inhaled. This initial step is crucial in maintaining optimal conditions for gas exchange and in reducing the risk of damage to the delicate tissues of the lungs from cold, dry air or pollutants. The filtering aspect helps in trapping large particles and microorganisms, preventing them from entering the lower respiratory tract.

The second mechanism involves the cough and sneeze reflexes. These reflexes are protective responses that expel irritants and excess mucus from the airways rapidly. This helps clear the respiratory passages of any potentially harmful substances and contributes to maintaining airway cleanliness.

Third, the mucociliary mechanism combines the action of mucus and cilia. Mucus traps dust, pathogens, and other particles that could harm the respiratory lining, while tiny hair-like structures called cilia move the mucus upwards towards the throat, where it can be swallowed or expelled. This mechanism plays a significant role in keeping the airways clear and protecting the lungs from infection.

Understanding these defense mechanisms is essential for recognizing how the respiratory system functions