Which cell type produces a pigment that affords the skin some protection against ultraviolet radiation?

Correct Answer: B

Rationale: Melanocytes, located in the stratum basale, produce melanin, a pigment that absorbs UV radiation, protecting skin cells from DNA damage and reducing cancer risk. Darkening (tanning) enhances this shield. Keratinocytes make keratin, a structural protein, not pigment. Dendrocytes (likely dendritic cells) are immune-related, not pigment-producing. Merkel cells detect touch, not UV protection. Melanin's role in UV defense, distributed to surrounding keratinocytes, is a well-established skin adaptation, making melanocytes the correct cell type.

Correct Answer: A

Rationale: Sebaceous glands are the skin's oil glands, secreting sebum into hair follicles to lubricate skin and hair, distinct from sweat glands. Eccrine (merocrine) glands secrete watery sweat to the surface. Apocrine glands secrete sweat into follicles. The term 'sebaceous' directly refers to oil production, a role not shared by the others, all of which are sudiferous glands. This specificity in skin histology identifies sebaceous glands as the oil producers, making them the correct synonym.

Correct Answer: C

Rationale: The hypodermis, or superficial fascia, is the subcutaneous layer of fat and connective tissue beneath the dermis, not part of the integument (epidermis and dermis). It's not the outer layer (epidermis) or inner layer of the skin proper (dermis is deeper within the integument). It is vascularized, with blood vessels supplying it, not reliant solely on diffusion like the epidermis. Its exclusion from the integument and role as a cushion and insulator define it anatomically, making this the correct characterization.

Correct Answer: B

Rationale: Keratinocytes, originating in the stratum basale, migrate upward, producing keratin and dying to form the stratum corneum, the dead, keratin-filled outer layer. Melanocytes produce melanin, not the corneum's structure. Dendrocytes (dendritic cells) are immune-related, not structural. Lymphocytes are in blood or lymph, not forming skin layers. Keratinocytes' differentiation into the corneum's protective barrier is a core epidermal process, making them the responsible cell type.

Correct Answer: B

Rationale: The integument comprises the epidermis and dermis, with the dermis as the deeper layer, including the papillary and reticular sublayers. The epidermis is superficial, with the stratum corneum as its topmost part. The papillary dermal layer is the upper dermis, not the deepest. The dermis, extending beneath the epidermis to the hypodermis boundary, is the integument's deepest component, housing glands and connective tissue, making it the correct answer.