Question

Which of the following occurs when bronchioles and systemic arterioles are affected?

a) Both dilate
b) Both constrict
c) One dilates, one constricts
d) No change occurs

Answer 1

When bronchioles are affected by low oxygen, they dilate to increase air flow, while systemic arterioles constrict to redirect blood to areas with better oxygenation. This response corrects the imbalance between ventilation and perfusion.

Step-by-step explanation:

When bronchioles are affected by a decrease in the partial pressure of oxygen, they tend to dilate. This is a compensatory mechanism that allows more air to flow into the affected areas to improve oxygenation. In contrast, when systemic arterioles are affected by the same decrease in oxygen, they constrict. This helps to redirect blood flow to better-ventilated areas of the lung. Therefore, in the case where ventilation is less than perfusion, the arterioles constrict and the bronchioles dilate to correct the imbalance.