According to the sensory homunculus, which specific region of the body is least sensitive?

• A. Lips
• B. Tongue
• C. Back
• D. Fingertips

Answer: (C)

Verified step by step guidance

1. Understand the concept of the sensory homunculus: The sensory homunculus is a visual representation of the somatosensory cortex in the brain, which maps out the sensitivity of different body regions based on the density of sensory receptors.
2. Recognize that regions with a higher density of sensory receptors (e.g., fingertips, lips, tongue) are more sensitive and occupy larger areas on the sensory homunculus.
3. Compare the listed body regions: Lips, tongue, fingertips, and back. The lips, tongue, and fingertips are known to have a high density of sensory receptors, making them highly sensitive.
4. Identify the back as the region with the least sensitivity: The back has a lower density of sensory receptors compared to the other regions listed, resulting in less sensitivity and a smaller representation on the sensory homunculus.
5. Conclude that the back is the correct answer based on its lower sensitivity and smaller representation on the sensory homunculus compared to the other regions.