Specialized sensory receptors located outside the central nervous system that detect changes in the chemical composition of blood, particularly oxygen (O₂), carbon dioxide (CO₂), and pH levels. The primary peripheral chemoreceptors are the carotid bodies, situated near the bifurcation of the carotid arteries, and the aortic bodies, located along the aortic arch.
Peripheral chemoreceptors play a critical role in regulating respiratory and cardiovascular responses to maintain homeostasis. They are highly sensitive to hypoxia (low oxygen levels) and, to a lesser extent, hypercapnia (elevated CO₂ levels) and acidosis (low blood pH). When activated, they send signals to the brainstem via afferent nerves, such as the glossopharyngeal nerve (from the carotid bodies) and the vagus nerve (from the aortic bodies), stimulating an increase in ventilation and adjustments in heart rate and blood pressure to restore normal blood gas levels.
These chemoreceptors are vital for survival, particularly in acute situations like high-altitude exposure, respiratory disorders, or conditions that impair oxygen delivery or CO₂ elimination. Their function is tightly integrated with central chemoreceptors, forming a comprehensive system for monitoring and responding to changes in the body’s internal environment.
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