The primary function of sweat glands in the skin is:

Correct Answer: B

Rationale: Sweat glands, especially eccrine, primarily regulate temperature by secreting sweat for evaporative cooling and excrete waste like salts and urea, dual roles in homeostasis. Lubrication is sebum's job, melanin production is melanocytes', and UV protection is melanin's effect, not glands'. Sweat's cooling and minor excretory functions define their primary purpose, making this the accurate answer.

Correct Answer: B

Rationale: The dermis maintains elasticity and prevents wrinkles via collagen and elastin fibers, which degrade with age, causing sagging. The epidermis provides a barrier, not elasticity. The hypodermis (subcutaneous tissue) insulates but doesn't directly affect wrinkles. The dermis's structural proteins, produced by fibroblasts, are key to skin firmness, making it the correct layer.

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.