Question

Predict what would happen if a lung's visceral membrane were pulled away from its parietal membrane still attached to the chest wall.

A) Excess serous fluid would quickly accumulate in the newly formed space.
B) Only the parietal membrane would continue producing serous fluid.
C) Loss of membrane adhesive force would cause lung collapse.
D) The lung would get much larger than normal when inhaling air.

Answer 1

If the visceral pleura were pulled away from the parietal pleura, the surface tension and adhesive force that keep the lungs expanded would be lost, causing the lung to collapse, which is known as pneumothorax.

Step-by-step explanation:

The Loss of membrane adhesive force would cause lung collapse. Pleural membranes, specifically the visceral pleura attached to the lung and the parietal pleura attached to the chest wall, play crucial roles in lung function. The pleural cavity, the space between these membranes, contains a small amount of pleural fluid that lubricates and allows for smooth movement of the lungs during respiration. The pleural fluid also creates surface tension, which helps maintain the adhesive force holding the lung to the thoracic wall. If the visceral pleura were pulled away from the parietal pleura, this tension would be lost, leading to a collapse of the lung, or pneumothorax.

Key to understanding this is the concept of negative intrapleural pressure, maintained by the balance of forces within the thorax. The lungs are naturally inclined to collapse due to their elasticity, countered by the chest wall which tends to expand outwardly. The pleural fluid prevents these opposing forces from causing a problem, but any disruption, such as separating the visceral pleura from the parietal pleura, would disrupt the balance, potentially leading to a lung collapse.