Final answer:
High partial pressure of O2 in an alveolus leads to the dilation of blood vessels, increasing blood flow to the area, which helps optimize the oxygenation of blood.
Step-by-step explanation:
When there is dead space in an alveolus, the high partial pressure of O2 will act on smooth muscles to dilate blood vessels which will increase blood flow. This mechanism is part of the body's response to ensure efficient gas exchange. The alveoli are air sacs in the lungs where oxygen and carbon dioxide are exchanged with the blood. When the partial pressure of oxygen is high, it signals the body that the alveolus is receiving good ventilation. In response, pulmonary arterioles dilate to increase blood flow to that alveolus, facilitating the diffusion of oxygen into the bloodstream. This adaptation helps maintain the balance between ventilation (airflow) and perfusion (blood flow) within the lungs, optimizing the oxygenation of blood.