Peripheral chemoreceptors are most sensitive to what changes?

Peripheral chemoreceptors, primarily located in the carotid bodies and aortic bodies, play a crucial role in regulating respiratory function by sensing changes in blood chemistry. They are particularly sensitive to decreases in arterial partial pressure of oxygen (PaO2).

When PaO2 levels drop, the peripheral chemoreceptors send signals to the respiratory centers in the brain to increase the depth and rate of breathing. This response is fundamental for maintaining adequate oxygen supply to the tissues, especially under conditions where oxygen levels may be compromised, such as during hypoxia or at high altitudes.

While increased levels of carbon dioxide (PaCO2) can also stimulate chemoreceptors, it is the decreased oxygen levels that trigger the most significant response, making the body more alert to hypoxic conditions. The other options, though they may impact respiratory drive to some degree, do not have the same direct and potent effect as decreased PaO2 in activating peripheral chemoreceptors.