Question

Between breaths the interpleural pressure is approximately _______mm Hg less than atmospheric pressure.

• A. $1$
• B. $4$
• C. $8$
• D. $10$

Answer 1

The correct option is B $4$

Changes in the hydrostatic pressure of the intrapleural fluid (intrapleural pressure, Pip) cause the lungs and thoracic wall to move in and out during normal breathing. In between the breaths, Pip decreases relative to atmospheric pressure by 4 mm Hg.

so, the correct answer is '4'