Final answer:
When the upper respiratory passages are bypassed with a tracheotomy, the air entering the trachea may be different from air normally entering this canal and can cause problems for the patient.
Step-by-step explanation:
When the upper respiratory passages are bypassed with a tracheotomy, the air entering the trachea bypasses the normal filtration and conditioning processes that occur in the nasal cavity and pharynx. This means that the air entering the trachea may be colder, drier, and contain more particles, such as dust and pollutants. These differences in air quality can cause several problems for the patient, including dryness of the airways, increased risk of infection, and irritation of the lungs.