If the thoracic wall is punctured, air leaking in will cause the lung to collapse.Thus in the normal, intact thoracic cavity,

Question

Quizplus · Accepted Answer

In the normal, intact thoracic cavity, the pleural cavity has a slight negative pressure which helps to keep the alveoli partly inflated. This negative pressure is created by the opposing forces of the lungs trying to recoil inward and the chest wall trying to recoil outward. This negative pressure keeps the lungs expanded and allows for efficient gas exchange. If air leaks into the pleural cavity, such as in the case of a punctured thoracic wall, this negative pressure is lost and the lung collapses. Therefore, option C is the correct choice. Options A and D are incorrect because lung expansion is an active process involving the contraction of the diaphragm and intercostal muscles. Option B is incorrect because air pressure is not the same inside and outside of the thoracic cavity. Option E is also incorrect because increasing the volume of the thoracic cavity would increase the tension between the pleural membranes, not decrease it.

If the Thoracic Wall Is Punctured, Air Leaking in Will