Final answer:
In pneumothorax, the flow-volume loop reveals a decrease in the maximum volume of air the lungs can hold and reduced flow rates during inhalation and exhalation, due to disruption in the lung's ability to expand and contract effectively.
Step-by-step explanation:
The state of a pneumothorax, or collapsed lung, involves a disruption of the normal negative pressure within the thoracic cavity that is crucial for proper lung function. In a healthy lung, during inhalation, the volume of the thorax increases, causing the diaphragm and intercostal muscles to contract, resulting in a decrease in air pressure within the lungs relative to atmospheric pressure as described by Boyle's Law. This negative pressure facilitates air rushing into the lungs, inflating the alveoli and allowing oxygen exchange.
However, in a pneumothorax scenario, this system is compromised. The flow-volume loop, which is a graphical representation of the amount of air (volume) exhaled and inhaled over time as well as the flow rate of air through the lungs, would show a decrease in the maximum volume of air the lung can hold, as part of the lung is no longer participating in gas exchange. Additionally, the flow rates during both inhalation and exhalation are reduced because the lung's elastic recoil is disrupted, affecting the lung's ability to expand and contract effectively.