Anatomy and Physiology II Practice Test

Which of the following structures is NOT part of the lower respiratory tract?

1. Lungs

2. Trachea

3. Bronchi

4. Nasal cavity

The correct answer is: Nasal cavity

The lower respiratory tract is defined as the portion of the respiratory system that is located below the larynx and includes structures that are directly involved in gas exchange. This encompasses the trachea, bronchi, and lungs, all of which play vital roles in transporting air to the areas where oxygen and carbon dioxide exchange occurs. The nasal cavity, on the other hand, is part of the upper respiratory tract. It is responsible for air intake, conditioning the incoming air (warming, moistening, and filtering), and providing a pathway for airflow to the lower respiratory structures through the pharynx and larynx. The distinction between upper and lower respiratory tract structures is based on their specific anatomical locations and functions in the respiratory process. In summary, the nasal cavity is not part of the lower respiratory tract because it functions primarily as an entry point for air rather than a site for gas exchange, which is the function of the structures found in the lower respiratory tract.