Which of the following is beneath the stratum corneum?

Correct Answer: C

Rationale: The stratum corneum is the outermost epidermal layer, and directly beneath it lies the stratum granulosum, where cells transition to form the keratinized surface. The stratum spinosum is deeper, below the granulosum, providing strength. The stratum basale is the deepest layer, far below the corneum. Since the question asks what is immediately beneath the stratum corneum, the stratum granulosum fits as the next layer in the epidermal structure, making it the correct answer.

Correct Answer: B

Rationale: The dermis, a thick layer beneath the epidermis, is a complex structure with multiple components and functions. It is highly vascular, with blood vessels supplying nutrients and aiding in thermoregulation. It contains reticular and elastic fibers for strength and flexibility, as well as smooth muscle (e.g., arrector pili muscles) and numerous nerve endings for sensation. However, it does not give rise to sebaceous and sweat glands. These glands originate from the epidermis during embryonic development, invaginating downward into the dermis as they mature. Sebaceous glands secrete oil, and sweat glands produce sweat, both budding from epidermal tissue, not dermal. This embryological distinction is critical: while the dermis hosts these glands and supports them with blood and nerve supply, their cellular origin is epidermal. The statement is false because it misattributes the developmental source of these glands, contradicting histological and developmental biology principles.

Correct Answer: C

Rationale: Skin coloration reflects physiological and genetic factors. Yellowish tones in some Oriental skin result from carotene, a dietary pigment accumulating in the stratum corneum, which is accurate. Tanning occurs when sunlight stimulates melanocytes to produce more melanin, darkening the skin as a UV shield, a correct pairing. Albinism, a hereditary condition, arises from defective melanin synthesis, leading to little or no pigmentation, also true. However, cyanosis a bluish skin tint occurs due to low oxygen levels in the blood (deoxygenated hemoglobin), not oxygenated blood, which appears red. This mismatch misrepresents cyanosis's cause, as oxygenated blood in capillaries gives skin a pinkish hue, while deoxygenation shifts it to blue. The error lies in linking cyanosis to the wrong blood state, contradicting basic circulatory and dermatological principles, making it the odd one out.

Correct Answer: C

Rationale: The hypodermis, or subcutaneous layer, is a fatty layer beneath the dermis that protects underlying organs by cushioning them, helps maintain body temperature through insulation, and serves as a long-term energy storage site via adipose tissue. However, it is not a source of blood vessels in the epidermis. The epidermis itself is avascular (lacking blood vessels), relying on diffusion from the papillary dermis, not the hypodermis, for nutrients. The hypodermis does contain larger blood vessels, but they supply the dermis, not directly the epidermis. This distinction in vascular anatomy excludes the hypodermis as a direct source for epidermal blood vessels, making it the correct choice for what is not a function.

Correct Answer: C

Rationale: Bleeding occurs when blood vessels are damaged, and the epidermis (stratum corneum, granulosum, bas fragility ale) is avascular, containing no blood vessels. The papillary dermis, the upper dermal layer, has a rich supply of capillaries that can bleed if cut. The stratum corneum is dead and superficial, the stratum granulosum is a thin transitional layer, and the stratum basale, while alive, relies on diffusion from dermal vessels, not having its own. A cut reaching the papillary dermis, just below the epidermis, would nick these capillaries, causing minor bleeding, making it the correct layer.