Final answer:
The volume of air that was inhaled when the pressure changed from -5 cm H2O to -7 cm H2O with a lung compliance of 0.5 L/cm H2O is calculated as a 1.0-liter decrease in volume. However, this decrease (exhalation) is not consistent with typical physiological breathing patterns where negative pressure represents inhalation.
Step-by-step explanation:
The question focuses on the concept of lung compliance, which is a measure of the lung's ability to stretch and expand. In the given scenario, the compliance of the lung is 0.5 L/cm H2O. To determine the volume of air inhaled when the pressure changes from -5 cm H2O to -7 cm H2O, we use the formula ΔV = C × ΔP, where ΔV is the change in volume, C is the compliance, and ΔP is the change in pressure. The change in pressure (ΔP) is equal to the final pressure minus the initial pressure, which is -7 cm H2O - (-5 cm H2O) = -2 cm H2O. Using the compliance value of 0.5 L/cm H2O, the calculation for the change in volume (ΔV) is as follows:
ΔV = 0.5 L/cm H2O × (-2 cm H2O) = -1.0 L.
The negative value indicates that 1.0 liter of air was exhaled (not inhaled) when the pressure increased (became more negative). It is important to note here that in terms of physiological implications, negative pressure typically means inhalation in the context of breathing, but a decrease or more negative pressure as described would usually denote an exhalation process in a mechanical context or an abnormal physiological situation.