Final answer:
Peripheral chemoreceptors in the aortic arch and carotid arteries are stimulated by low levels of dissolved oxygen in the blood, promoting increased respiratory rate to restore normal oxygen levels. These mechanisms, along with reciprocal cardiovascular responses, maintain adequate oxygen supply and remove CO2 to ensure normal functioning and prevent hypoxia or ischemia.
Step-by-step explanation:
Peripheral chemoreceptors located in the aortic arch and carotid arteries are stimulated when the arterial partial pressure of oxygen (PO2) falls below the normal range. A significant drop in PO2 levels—around 60 mm Hg or less—is required to activate these chemoreceptors. In such conditions, the peripheral chemoreceptors trigger an increase in respiratory rate to balance oxygen levels, given that they can only detect oxygen molecules dissolved in the blood and not those bound to hemoglobin. As such, normal blood oxygen saturation is crucial for the body's normal functioning, and the physiological mechanisms ensure that oxygen demand by the tissues is met, particularly under varying metabolic rates such as during exercise or at rest.
Furthermore, the cardiovascular system works in tandem with the respiratory system to adjust cardiac output and vessel dilation based on CO2 levels and pH changes, ensuring adequate oxygen delivery and CO2 removal from the cells. This is pivotal for maintaining blood pressure within a normal range and ensuring sufficient circulation to prevent potential ischemia or hypoxia. Therefore, the interplay between respiratory and cardiovascular systems is intrinsically linked to sustaining homeostasis.