Peripheral chemoreceptors

Peripheral chemoreceptors act principally to detect variation of the oxygen concentration in the arterial blood, whilst also monitoring arterial carbon dioxide and pH. They are located in the aortic body and carotid body, on the transverse aortic arch and on the common carotid artery, respectively. The carotid bodies are most sensitive to changes in partial pressure of arterial oxygen and pH. The aortic bodies are most sensitive to the content of arterial oxygen. In contrast, the central chemoreceptors are relatively insensitive to oxygen concentration, and thus to hypoxia.

The glomus cell senses a decrease or rise in blood oxygen levels in the carotid artery, and potassium ion-gates close, causing calcium to flow into the cytosol of the cell, releasing continual signal which is sent via cranial nerves IX and X, from the peripheral chemoreceptors to the brainstem. With a decrease in arterial oxygen tension and content or drop in plasma pH, the signal intensifies, and results in an increase in ventilation rate.