Final answer:
Peripheral chemoreceptors located in the aortic arch and carotid arteries stimulate an increase in respiratory activity when they detect abnormally low PO2 levels, thus enhancing oxygen uptake and carbon dioxide excretion.
Step-by-step explanation:
When peripheral chemoreceptors detect abnormally low partial pressure of oxygen (PO2) levels, specifically around 60 mm Hg or less, they elicit an increased respiratory response. These chemoreceptors, found within the aortic arch and carotid arteries, are sensitive to the levels of dissolved oxygen in the blood, as they cannot sense the oxygen bound to hemoglobin.
The primary function of this mechanism is to ensure an adequate supply of oxygen to the body's tissues and to remove excess carbon dioxide, which can result in lowered blood pH levels. A lower-than-normal level of oxygen stimulates these chemoreceptors to send signals to the cardiorespiratory centers in the brain, prompting an increase in the rate and depth of breathing, thus enhancing oxygen uptake and carbon dioxide elimination through the lungs.
This reaction also plays a part in the interrelationship between cardiovascular and respiratory control, which is essential for maintaining the correct balance of oxygen and carbon dioxide in response to the body's changing metabolic demands.