Which of the following tactile receptors respond to the vibration sense of 30 – 800 Hz?
**Core Concept:** Tactile receptors are specialized sensory neurons that detect various physical stimuli, including pressure, vibration, and temperature. In this question, we are focusing on the vibration sense, specifically the range of 30-800 Hz.
**Why the Correct Answer is Right:** Mechanoreceptors are the tactile receptors responsible for detecting mechanical stimuli, including vibration. There are two main types of mechanoreceptors: Pacinian corpuscles and Merkel cells. Pacinian corpuscles are the primary tactile receptors that respond to high-frequency vibrations (30-800 Hz). Merkel cells respond to low-frequency vibrations (below 30 Hz) and pressure stimuli.
**Why Each Wrong Option is Incorrect:**
A. Option A: Merkel cells primarily respond to low-frequency vibrations and pressure stimuli, making them incorrect for detecting high-frequency vibrations (30-800 Hz).
B. Option B: Pacinian corpuscles are the correct answer, as they respond to high-frequency vibrations (30-800 Hz). However, they also respond to low-frequency vibrations, so this option is not entirely incorrect.
C. Option C: Merkel cells respond to low-frequency vibrations and pressure stimuli, not high-frequency vibrations (30-800 Hz).
D. Option D: Merkel cells respond to low-frequency vibrations and pressure stimuli, making them incorrect for detecting high-frequency vibrations (30-800 Hz).
**Clinical Pearl:** Pacinian corpuscles are responsible for detecting high-frequency vibrations, which are important for various clinical scenarios, such as diagnosing deep tendon reflexes in clinical examination. A diminished or absent deep tendon reflex can be a sign of neurological disorders, peripheral nerve injury, or spinal cord injury.
**Correct Answer:** D. Merkel cells respond to low-frequency vibrations and pressure stimuli, not high-frequency vibrations (30-800 Hz).