Final answer:
The V/Q ratio measures the balance between lung ventilation and blood perfusion, and changes in lung compliance and resistance, due to diseases like fibrosis, asthma, or emphysema, can increase this ratio, while conditions creating a physiological shunt can decrease it, thereby affecting gas exchange.
Step-by-step explanation:
The V/Q ratio refers to the ventilation/perfusion ratio, an essential concept in understanding lung physiology and gas exchange. Variations in lung compliance and resistance significantly alter breathing and gas exchange. Restrictive diseases such as fibrosis decrease lung compliance, causing the airways to stiffen and collapse, which results in air entrapment and raises the V/Q ratio.
Conversely, obstructive diseases like asthma or emphysema increase resistance, leading to airway blockage and trapped air in the lungs, which can also elevate the V/Q ratio. Nevertheless, specific pathological conditions, like a physiological shunt due to infection or edema, can decrease ventilation without affecting perfusion, consequently lowering the V/Q ratio and impacting gas exchange. The management of V/Q mismatch, where changes in ventilation and perfusion occur, is crucial for effective respiration.