Question

Between breaths, the intrapleural 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

Intrapleural pressure is the pressure within the pleural cavity. It is always negative. This negative force acts as a suction to keep the lungs inflated. The negative intrapleural pressure is due to the surface tension of the alveolar fluid, the elasticity of the lungs, and the elasticity of thoracic wall. Changes in the intrapleural pressure contribute to the movement of air during ventilation. The intrapleural pressure between breathes is less than atmospheric pressure by about 4 mm Hg.