Step 1 - Respiratory System Questions

Physiology > Respiratory > USMLE/COMLEX 1 - Prep Questions

Q. In Pulmonary physiology, the lung is divided into three zones. The apex is Zone 1, the middle region is Zone 2, and the base is labelled as Zone 3. In a human-subject experiment, a physiologist applies low-level positive pressure ventilation while studying blood flow through the different lung zones. As gravity has an effect on blood and organs, which of the following will be noted in this experiment assuming the subject is standing?

Blood flow in Zone 3 will be driven by the difference between alveolar and venous pressures
Blood flow will be reduced in Zone 1
Blood flow will increase in Zone 2
Regional differences between blood flow will not be as great as differences in ventilation
Regardless of the participant’s position, blood flow will remain uneven throughout the lung zones
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