**Core Concept**
Volume receptors, also known as volume sensitive stretch receptors, are specialized sensors located in the walls of blood vessels and the heart. They play a crucial role in detecting changes in blood volume and pressure, triggering reflexes to maintain homeostasis.

**Why the Correct Answer is Right**
Volume receptors are activated by stretch in the blood vessel walls, which occurs when blood volume increases. This activation leads to the release of neurotransmitters that stimulate the sympathetic nervous system to constrict blood vessels and increase heart rate, thereby reducing blood volume and pressure. The juxtaglomerular apparatus in the kidney also senses changes in blood volume and pressure, influencing renin release to regulate blood pressure.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to volume receptors. Instead, it might refer to chemoreceptors, which detect changes in blood pH, oxygen, and carbon dioxide levels.
**Option B:** This option is incorrect because it describes baroreceptors, which are sensitive to changes in blood pressure, not volume.
**Option C:** This option is incorrect because it describes osmoreceptors, which detect changes in blood osmolality, not volume.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that volume receptors are part of the volume reflex, which helps maintain blood pressure homeostasis. The volume reflex is often disrupted in conditions like heart failure, where fluid overload can lead to activation of volume receptors, resulting in sodium retention and further fluid overload.

**Correct Answer: D. Volume sensitive stretch receptors.**