Final answer:
When you hyperventilate, the arterial partial pressure of carbon dioxide decreases and ventilation increases, leading to an increased blood pH due to the excessive expulsion of CO₂.
Step-by-step explanation:
If you hyperventilate, the changes that would occur in arterial partial pressure of carbon dioxide (PCO₂) and ventilation are that PCO₂ would decrease and ventilation would increase. This is because hyperventilation involves rapid and deep breathing, which leads to an increased expulsion of carbon dioxide from the body, thus reducing its partial pressure in the blood. As a result, the correct answer is b. PCO₂ decreases, ventilation increases.
Increased ventilation can lead to increased blood pH, also known as respiratory alkalosis. The mechanism behind this is that by removing more carbon dioxide (which combines with water to form carbonic acid, thus increasing H+ ions in the blood), the blood pH rises as it becomes more alkaline. This is an example of how respiratory processes can influence blood chemistry.