Final answer:
Atelectasis is the collapse of lung tissue, while pneumothorax is the presence of air in the pleural space causing a collapsed lung, often due to connective tissue abnormalities. Both conditions disrupt normal pulmonary ventilation by altering the pressures necessary for lung expansion and contraction.
Step-by-step explanation:
The difference between atelectasis and pneumothorax is primarily where the disturbance occurs. Atelectasis involves collapsed lung tissue due to various causes such as obstruction of the airways or by pressure from outside the lung. In contrast, pneumothorax involves air entering the pleural space, the area between the lung and chest wall, which disrupts the negative pressure needed to keep the lungs inflated. A spontaneous pneumothorax, for example, is often thought to be related to subtle abnormalities in connective tissue leading to a collapsed lung.
During normal pulmonary ventilation, the movement of air into and out of the lungs is driven by pressure differences. The delicate balance between intrapleural pressure and intra-alveolar (intrapulmonary) pressure is essential for the lungs to function properly. Any disruption to this balance, such as in pneumothorax or atelectasis, can significantly impair respiration.