How does the body defend itself from microorganisms and other harmful substances that enter the airway during the breathing process?
The epithelium of the airway is a ciliated epithelium and has mucus-secreting specialized cells. The secreted mucus covers the internal wall of the airway retaining organisms and foreign particles that then are swept by the cilia of the epithelium. In the mucous ciliated epithelium of the airway there is also intense activity of the immune system with antibodies and leukocytes inactivating and destroying foreign agents. Other defense mechanisms of the airway are the sneeze and the cough. They help the elimination of solid and semifluid particles like pathologic residuals (sputum) and accidentally aspired objects.
