Stretch stimulus is mediated by which of the following receptors?
**Core Concept**
Stretch receptors are mechanoreceptors found in the walls of blood vessels and other organs that respond to changes in pressure and stretch. They play a crucial role in regulating cardiovascular function and blood pressure.
**Why the Correct Answer is Right**
The correct answer is mediated by baroreceptors, which are a type of stretch receptor found in the walls of the carotid sinus and aortic arch. When the stretch receptors are activated by increased blood pressure, they send signals to the brainstem, which responds by decreasing sympathetic tone and increasing parasympathetic tone to lower blood pressure. This reflex is known as the baroreceptor reflex.
**Why Each Wrong Option is Incorrect**
**Option A:** is incorrect because chemoreceptors are responsible for detecting changes in blood pH, CO2, and oxygen levels, not stretch.
**Option B:** is incorrect because thermoreceptors detect changes in temperature, not stretch.
**Option C:** is incorrect because proprioceptors detect changes in muscle length and tension, not stretch in blood vessels.
**Clinical Pearl / High-Yield Fact**
The baroreceptor reflex is a critical mechanism for maintaining blood pressure homeostasis, and its dysfunction can lead to conditions such as hypertension and orthostatic hypotension.
**Correct Answer:** C. Baroreceptors