Peripheral chemoreceptors respond to hypoxia by oxygen sensitive:
**Core Concept**
Peripheral chemoreceptors, located in the carotid and aortic bodies, play a crucial role in detecting changes in the chemical composition of arterial blood. These receptors are sensitive to decreases in oxygen levels, increases in carbon dioxide levels, and decreases in pH, triggering a response to increase ventilation and restore normal blood gas levels.
**Why the Correct Answer is Right**
Peripheral chemoreceptors respond to hypoxia through the action of oxygen-sensitive enzymes, specifically the enzyme cytochrome c oxidase. This enzyme is embedded in the mitochondrial inner membrane and is essential for the electron transport chain. When oxygen levels are low, cytochrome c oxidase is inhibited, leading to a decrease in ATP production. This decrease in ATP production triggers a signaling cascade that ultimately results in the activation of the chemoreceptor, leading to an increase in ventilation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the response of peripheral chemoreceptors to hypoxia. While potassium channels are involved in the regulation of cellular excitability, they are not directly involved in the response of peripheral chemoreceptors to low oxygen levels.
**Option B:** This option is incorrect because the enzyme involved in the response of peripheral chemoreceptors to hypoxia is cytochrome c oxidase, not carbonic anhydrase. Carbonic anhydrase is involved in the regulation of pH by catalyzing the conversion of carbon dioxide and water to bicarbonate and hydrogen ions.
**Option C:** This option is incorrect because the response of peripheral chemoreceptors to hypoxia is not mediated by the activation of the sodium-potassium pump. While the sodium-potassium pump is essential for maintaining cellular homeostasis, it is not directly involved in the response of peripheral chemoreceptors to low oxygen levels.
**Clinical Pearl / High-Yield Fact**
Peripheral chemoreceptors are sensitive to decreases in oxygen levels, but it is worth noting that they are not the primary sensors of oxygen in the body. The primary sensors of oxygen are the mitochondrial sensors, which are located in the mitochondria and are sensitive to decreases in oxygen levels. The mitochondrial sensors play a crucial role in regulating cellular metabolism and energy production in response to changes in oxygen levels.
**Correct Answer:** C. cytochrome c oxidase