What effect does increased blood acidity have on ventilation?

Increased blood acidity, often measured as a decrease in pH, plays a significant role in regulating ventilation through its effects on chemoreceptors. When blood becomes more acidic, it typically indicates an increase in carbon dioxide levels (hypercapnia) or a buildup of lactic acid and other metabolic byproducts. The body responds to these changes to restore homeostasis.

Chemoreceptors located in the medulla oblongata and in peripheral arteries (such as the carotid and aortic bodies) are sensitive to changes in blood pH and CO₂ levels. When blood acidity increases, these chemoreceptors stimulate the respiratory center in the brain to increase the rate and depth of breathing (ventilation). This action enhances the elimination of carbon dioxide from the body, which in turn lowers blood acidity back toward a normal pH range.

Thus, the correct answer is that increased blood acidity increases ventilation, as the body actively responds to restore balance and ensure adequate oxygenation while removing excess carbon dioxide.