Anatomy and Physiology II Practice Test

What structures make up the lower respiratory tract?

1. Trachea, lungs, and bronchial tree

2. Bronchi, alveoli, and diaphragm

3. Larynx, trachea, and bronchi

4. Pharynx, bronchioles, and nasal cavity

The correct answer is: Trachea, lungs, and bronchial tree

The lower respiratory tract consists of structures that are primarily responsible for the conduction of air to and from the lungs, as well as the sites of gas exchange. The trachea is a vital airway that transports air down into the lungs. Once inside the lungs, the trachea bifurcates into the bronchi, which further divide into smaller branches known as the bronchial tree. Within these branches lie the alveoli, where the actual exchange of oxygen and carbon dioxide occurs. This definition aligns with the correct choice, which identifies the trachea, lungs, and bronchial tree as constituents of the lower respiratory tract. Each of these components plays a crucial role in ensuring that air is delivered to the sites of gas exchange in the lungs effectively. The other options focus on various structures but either include parts of the upper respiratory tract or do not encompass the full range of lower respiratory components. For instance, the larynx and pharynx are part of the upper respiratory system, while the diaphragm, although important for respiration, is a muscle and not part of the airway itself. Understanding the distinction between these structures is key to recognizing the functions and roles they play in the respiratory system.