Peripheral and central chemoreceptors respond to?
**Core Concept**
The peripheral and central chemoreceptors play a crucial role in regulating breathing by detecting changes in the chemical composition of the blood, particularly the concentration of carbon dioxide (CO2), oxygen (O2), and pH levels.
**Why the Correct Answer is Right**
These chemoreceptors respond to an increase in CO2 levels, which leads to a decrease in pH (acidosis), and an increase in hydrogen ions (H+) in the blood. This response is mediated by the stimulation of chemoreceptor cells in the carotid bodies and aortic bodies (peripheral chemoreceptors) and in the medulla oblongata (central chemoreceptors). The peripheral chemoreceptors are primarily sensitive to decreases in O2 levels, while the central chemoreceptors are more responsive to changes in CO2 levels and pH.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the peripheral and central chemoreceptors do not primarily respond to changes in blood pressure.
* **Option B:** This option is incorrect because while the peripheral chemoreceptors are sensitive to decreases in O2 levels, they are not the primary responders to changes in CO2 levels and pH.
* **Option D:** This option is incorrect because the peripheral and central chemoreceptors do not primarily respond to changes in body temperature.
**Clinical Pearl / High-Yield Fact**
The stimulation of peripheral chemoreceptors can lead to an increase in respiratory rate and depth, resulting in hyperventilation, which can help to reduce CO2 levels and pH in the blood.
**Correct Answer: C. Changes in CO2 levels and pH.**