Anatomy and Physiology II Practice Test

What is the correct order of the four progressively smaller air tubes leading to the alveolar sacs?

1. Primary bronchi, secondary bronchi, bronchioles, alveoli

2. Primary bronchi, secondary bronchi, bronchioles, and alveolar ductus

3. Trachea, bronchi, bronchioles, alveolar sacs

4. Bronchioles, trachea, alveolar ducts, alveoli

The correct answer is: Primary bronchi, secondary bronchi, bronchioles, and alveolar ductus

The correct order of the four progressively smaller air tubes leading to the alveolar sacs is accurately represented by the option that includes primary bronchi, secondary bronchi, bronchioles, and alveolar ductus. To understand this order, it's helpful to clarify how air travels through the respiratory system. Air enters the trachea, which splits into the primary bronchi, leading to each lung. As these bronchi divide, they branch into secondary bronchi, also known as lobar bronchi, corresponding to the lobes of the lungs. From there, the air continues into the smaller bronchioles, which are narrower passages that further divide and lead to the alveolar ducts. The final destination, the alveolar sacs, are clusters of alveoli where gas exchange occurs. Understanding these anatomical structures and their sequence is crucial for grasping how the respiratory system functions in delivering air to the site of gas exchange. The option chosen correctly outlines this series of airways, reflecting the necessary progression from larger to smaller conductance tubes before reaching the alveolar sacs.