The Mechanics of Breathing

Free Response

How would increased airway resistance affect intrapleural pressure during inhalation?


Increased airway resistance increases the volume and pressure in the lung; therefore, the intrapleural pressure would be less negative and breathing would be more difficult.

Explain how a puncture to the thoracic cavity (from a knife wound, for instance) could alter the ability to inhale.


A puncture to the thoracic cavity would equalize the pressure inside the thoracic cavity to the outside environment. For the lung to function properly, the intrapleural pressure must be negative. This is caused by the contraction of the diaphragm pulling the lungs down and drawing air into the lungs.