What effect do peripheral chemoreceptors have when responding to high levels of H+ ions?

Peripheral chemoreceptors are specialized sensory receptors located in areas such as the carotid bodies and aortic bodies, and they play a critical role in the body's homeostatic response to changes in blood chemistry. When there are high levels of H+ ions, indicating an increase in acidity (or a decrease in pH), these chemoreceptors are stimulated.

The activation of peripheral chemoreceptors in response to elevated H+ ions leads to an increase in ventilation rates. This occurs because the body attempts to restore acid-base balance; an increase in respiratory rate allows for enhanced expulsion of carbon dioxide (CO2). Since CO2 is acidic when combined with water in the body, reducing its level through increased ventilation helps to diminish the concentration of H+ ions, thereby restoring normal pH levels in the blood.

This response is crucial, especially during conditions such as metabolic acidosis, where the body must compensate rapidly to maintain homeostasis. Therefore, when peripheral chemoreceptors detect high H+ levels, they signal for an increase in respiration, which is why the correct answer is an increase in ventilation.