What type of cells are known as slow touch receptors?

• A. Keratinocytes
• B. Type I muscle fibers
• C. Merkel cells
• D. Adipocytes

Answer: (C)

Merkel cells are specialized mechanoreceptors located in the skin, particularly in areas that are sensitive to touch, such as fingertips and the palms of the hands. They play a crucial role in providing the sensation of light touch and are known for their slow adaptation, meaning they continue to respond to a stimulus over a longer period compared to other types of touch receptors. This allows them to detect sustained pressure and fine details, making them essential for tactile discrimination.

Understanding the function of Merkel cells helps clarify why they are classified as slow touch receptors. They are distinct from other types of cells involved in touch sensation, such as Meissner's corpuscles, which are considered rapidly adapting receptors. In contrast, keratinocytes do not have a direct role in touch sensation; they are the primary cells of the epidermis, involved in protective functions. Type I muscle fibers relate to muscle contraction and are not associated with sensory perception. Adipocytes are fat cells that store energy and have no role in touch sensation. Thus, the designation of Merkel cells as slow touch receptors aligns with their specialized role in tactile perception and adaptation.