Which skin function is responsible for detecting extreme temperature changes and potentially harmful stimuli?

Correct Answer: B

Rationale: Sensation detects extreme temperature changes (thermoreceptors) and harmful stimuli (nociceptors for pain), alerting the body to potential damage. Thermoregulation adjusts temperature, lubrication moisturizes, and vitamin D synthesis uses UV, none sensing stimuli. The skin's sensory receptors, embedded in the dermis and epidermis, enable this protective awareness, making sensation the correct function.

Correct Answer: B

Rationale: Transudate is a fluid that is clear, consisting mainly of water and electrolytes, with low protein content, and it results from imbalances in hydrostatic or osmotic pressure, often seen in conditions like heart failure. Exudate, by contrast, is thicker, containing proteins, cells, and debris, typically from inflammation or infection, and is not clear. Serosanguineous fluid is a mix of serum and blood, giving it a pinkish or reddish tint, not purely clear. Induration refers to hardened tissue, not a fluid. Since the question specifies 'water and electrolytes (clear),' transudate fits the description best as it matches the characteristics of a clear, watery fluid with electrolytes.

Correct Answer: B

Rationale: The epidermis has five layers, and the stratum corneum is the outermost, consisting of dead, flattened keratinocytes that form a protective barrier. The stratum basale is the deepest layer, where new cells are generated. The stratum spinosum lies above it, providing strength, followed by the stratum granulosum, where cells begin to die and form keratin. The stratum corneum, being the topmost layer exposed to the environment, serves as the skin's primary defense against external factors, making it the correct answer.

Correct Answer: C

Rationale: Eczema, particularly atopic dermatitis, is a chronic condition causing an itchy, blistering rash, often with small fluid-filled vesicles that can weep or crust. Keloids are firm scars, not rashes. Seborrhea produces oily scales, not blisters. Urticaria causes itchy welts, but they're typically not blistering. Eczema fits the description of a rash that is both blistering (in acute phases) and intensely itchy, aligning with its clinical presentation, making it the correct choice.

Correct Answer: C

Rationale: Epidermal layers have distinct roles and compositions. The stratum germinativum is the basal layer where cell division occurs, producing cells that eventually keratinize, but it is not primarily associated with keratin itself. The stratum corneum, the outermost layer, is packed with keratin, not melanocytes, which are found in the stratum germinativum and produce melanin. The stratum granulosum is where keratinization begins, with cells accumulating keratin as they die and move upward, making it a fitting match for keratin. The stratum lucidum, present only in thick skin, consists of dead, keratinized cells but lacks blood vessels, which are exclusive to the dermis. The correct pairing hinges on the layer most directly tied to keratin production and accumulation. The stratum granulosum's role in this process forming keratohyalin granules and initiating the transition to the stratum corneum makes it the strongest match, aligning with histological descriptions of epidermal differentiation and keratin's protective function.