What is the main difference between Merkel's disks and Meissner's corpuscles?

• A. Meissner's Fast; Merkel's Slow
• B. Merkel's Slow; Meissner's Fast
• C. Merkel's Fast; Meissner's Slow
• D. Meissner's Slow; Merkel's Fast

Answer: (B)

The main idea is how each receptor responds over time to a constant touch — its adaptation rate. Merkel's discs are slowly adapting receptors, meaning they continue to fire as long as the pressure is present, giving detailed information about sustained contact, texture, and shape with high spatial resolution. Meissner's corpuscles are rapidly adapting receptors, so they respond mainly at the onset and offset of light touch and during movement, signaling dynamic changes rather than a steady pressure.

So, the best pairing is Merkel's slow and Meissner's fast because it matches each receptor’s firing pattern to its functional role: continued response for sustained contact with Merkel's discs, and quick, brief responses for detecting changes with Meissner's corpuscles.

Options that swap the adaptation rates don’t fit because they assign the slow adaptation to Meissner's or the fast adaptation to Merkel's, which contradicts what each receptor type does.