Which layer of the skin contains Pacinian corpuscles, specialized for detecting pressure and vibration?

Correct Answer: B

Rationale: Pacinian corpuscles, deep pressure and vibration sensors, are located in the dermis, often near its border with the hypodermis, within the reticular layer. The epidermis, avascular and superficial, lacks such receptors. The hypodermis (subcutaneous tissue) may contain some, but they're primarily dermal, integrated with nerve networks there. The dermis's role as the sensory and structural layer, housing various receptors, makes it the correct location for these lamellated corpuscles.

Correct Answer: B

Rationale: Meissner's corpuscles, in the upper dermis, detect light touch and low-frequency pressure, enabling fine tactile sensation like texture. Pain is nociceptors' domain, temperature changes are thermoreceptors', and sweat production is glandular, not receptor-related. Their location and sensitivity to gentle contact distinguish them in the skin's sensory system, making this their primary role.

Correct Answer: A

Rationale: Pacinian corpuscles, deep in the dermis, detect pressure and vibration, responding to mechanical stimuli with their lamellated structure, aiding in sensing heavy touch. Light touch and texture are Meissner's role, temperature changes are thermoreceptors', and sweat production is glandular. Their deep placement and vibration sensitivity distinguish them, making this their primary role.

Correct Answer: B

Rationale: Skin synthesizes vitamin D via UV conversion of 7-dehydrocholesterol, essential for calcium absorption in the gut and bone health, preventing conditions like rickets. Blood clotting needs vitamin K, digestion involves enzymes, and temperature regulation uses sweat, none vitamin D-dependent. This metabolic role, supporting skeletal integrity, makes it the correct essential function.