A person has acne. You tell them the reason(s) are because: (You may pick more than one answer)

Correct Answer: B

Rationale: Acne arises from multiple factors, but excess sebum is a primary cause. Sebaceous glands produce sebum, an oil that lubricates skin and hair. Overproduction, often triggered by hormonal changes (e.g., androgens in puberty), clogs hair follicles, creating a breeding ground for Propionibacterium acnes bacteria. This leads to inflammation, forming pimples. Hypersecretion of hormones, like testosterone, drives this excess sebum, making it a linked cause, though the question allows single selection, prioritizing sebum's direct role. Excess carotene affects skin color, not oil production or acne. Poor hygiene ('wash your face') can worsen acne by allowing bacterial buildup, but it's not the root cause overwashing may even irritate skin. Bacterial infection is a secondary factor after sebum clogs pores. Dermatological consensus highlights sebum's role in acne pathogenesis, with hormonal influence as a trigger, distinguishing it from dietary pigments or hygiene alone as the most immediate explanation.

Correct Answer: C

Rationale: The stratum corneum, the outermost epidermal layer, is composed of dead, keratin-filled cells packed tightly together, with glycolipids in the extracellular spaces acting as a waterproof sealant. This structure makes it a robust barrier against water loss, pathogens, and abrasion. Rapid division of melanocytes and keratinocytes occurs in the stratum basale, not the corneum, which is avascular and lacks blood capillaries those are in the dermis. Epidermal ridges, forming fingerprints, are in the dermis and basal epidermis, not the corneum. The keratin and glycolipid composition is a defining feature, critical to its protective role, distinguishing it from deeper, living layers.

Correct Answer: C

Rationale: The stratum germinativum, also called the stratum basale, is the deepest epidermal layer where keratinocytes rapidly divide via mitosis to replenish the epidermis, replacing cells lost from the surface. The stratum lucidum, in thick skin, is a thin, dead layer above the basale, not dividing. The papillary and reticular dermal layers are in the dermis, containing connective tissue, not keratinocytes. The germinativum's name (from 'germinate') reflects its role as the regenerative base, a key feature of epidermal renewal confirmed by histological studies.

Correct Answer: D

Rationale: Sebaceous glands secrete sebum, an oily substance, into hair follicles to lubricate hair and skin, found in the dermis. Apocrine glands secrete sweat into hair follicles, not oil. Eccrine glands secrete watery sweat directly to the skin surface via ducts. Ceruminous glands produce cerumen (earwax), not oil for hair follicles. Sebaceous glands' association with follicles and their oily output distinguish them in skin physiology, making them the correct gland type for this function.

Correct Answer: A

Rationale: The epidermis is the outermost skin layer, encompassing sublayers like the stratum corneum and germinativum, serving as the body's protective shield. The dermis lies beneath it, with the papillary dermal layer as its upper part, still deeper than the epidermis. The stratum germinativum (basale) is the deepest epidermal sublayer, not the most superficial. As a whole, the epidermis sits atop the dermis, making it the most superficial layer in skin anatomy, consistent with its role as the first barrier to the environment.