How do arterial chemoreceptors respond when oxygen levels in the blood fall?

When oxygen levels in the blood fall—a condition known as hypoxia—the body relies on peripheral chemoreceptors to detect the change and trigger a regulatory response.

The primary arterial chemoreceptors are the carotid bodies, located in the neck, and the aortic bodies, located near the aortic arch. These organs respond specifically to the partial pressure of oxygen in the arterial blood, rather than the total oxygen content bound to hemoglobin.1

As the partial pressure of oxygen decreases, the sensory nerves from the carotid bodies increase their firing rate hyperbolically. This increased neural activity signals the brain to augment both the rate and depth of ventilation. By increasing breathing, the body works to restore oxygen levels to their physiological norm. While both carotid and aortic bodies respond to hypoxia, the carotid bodies are the primary sensors for these changes, whereas the aortic bodies are more involved in mediating the cardiovascular effects of low oxygen.12