Question

Which among the following is NOT a physical sense?

• A. Hearing
• B. Touch
• C. Smell
• D. Temperature

Hint:

To classify senses, identify the stimulus: mechanical, acoustic, or thermal stimuli trigger physical senses, while molecular interactions with receptors trigger chemical senses (smell and taste).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Human sensory perception is divided into physical senses and chemical senses, based on the nature of the stimulus and the receptors involved.

Step 2: Detailed Explanation:
Let us classify each of the listed senses:
1. Hearing: This is a physical sense mediated by mechanoreceptors in the inner ear (cochlea) that respond to physical sound pressure waves.
2. Touch: This is a physical sense mediated by mechanoreceptors in the skin that respond to physical pressure, shear, or mechanical deformation.
3. Temperature (Thermoreception): This is a physical sense mediated by thermoreceptors that respond to changes in thermal energy and heat flux.
4. Smell (Olfaction): This is a chemical sense.
Olfactory receptors in the nasal cavity respond to volatile chemical molecules that bind to specific G-protein coupled receptors.
Taste (gustation) is also a chemical sense, as it detects dissolved chemical compounds.

Step 3: Final Answer:
Therefore, smell is categorized as a chemical sense rather than a physical sense.