Final answer:
The medical term for a collapsed lung is spontaneous pneumothorax, often related to connective tissue abnormalities, resulting in the trapping of air within the lung tissue.
Step-by-step explanation:
The proper medical term for a collapsed lung is spontaneous pneumothorax. This condition is thought to be related to subtle abnormalities in connective tissue. A collapsed lung can also occur due to physiological reasons, such as a physiological dead space in the lung tissue where air gets trapped, possibly from a puncture wound. Conditions like COPD, which were previously referred to as chronic bronchitis or emphysema, involve a breakdown of connective tissues reducing the number and elasticity of alveoli, leading to trapped air in the lungs and reduced gas exchange. Similarly, restrictive diseases such as respiratory distress syndrome and pulmonary fibrosis also decrease lung compliance, making the lungs stiff and fibrotic, causing intrapleural pressure to be more positive and thus the airways to collapse upon exhalation, trapping air in the lungs. This significantly affects Forced or functional vital capacity (FVC).