Which layer of the skin contains adipose (fat) tissue that serves as insulation and energy storage?

Correct Answer: C

Rationale: The hypodermis, also called subcutaneous tissue, contains adipose tissue that insulates the body against heat loss and stores energy as fat reserves. The epidermis is a thin, avascular layer of epithelial cells, lacking fat. The dermis has connective tissue, glands, and vessels, but not significant adipose. 'Subcutaneous tissue' is synonymous with hypodermis, reinforcing its role. The hypodermis's fat content, cushioning organs and providing a calorie reserve, distinguishes it from the skin's upper layers, making it the correct answer.

Correct Answer: A

Rationale: The subcutaneous tissue (hypodermis) attaches the skin to underlying muscles and bones via loose connective tissue and fat, allowing mobility while securing position. UV protection is the epidermis's role via melanin. Sweat production occurs in the dermis, not hypodermis. Hair follicle nourishment is dermal, via blood and sebum. The hypodermis's anchoring function, cushioning and connecting, makes attachment its primary purpose, per anatomical structure.

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.