Another name for oil glands in the skin is:

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: 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.

Correct Answer: C

Rationale: Melanin, produced by melanocytes in the stratum basale, is the pigment responsible for skin color, ranging from light to dark tones, and absorbs UV radiation to protect underlying cells from DNA damage. Melatonin, a hormone from the pineal gland, regulates sleep, not skin color. Hemoglobin, in red blood cells, gives a pinkish hue via dermal blood vessels but isn't a skin pigment or UV shield. Collagen, a dermal protein, provides structure, not pigmentation or UV protection. Melanin's dual role in coloration and photoprotection, darkening with UV exposure (tanning), makes it the correct pigment, per dermatological understanding.

Correct Answer: A

Rationale: The epidermis grows hair and nails via specialized structures: hair from follicles' matrix cells in the epidermal root, and nails from the nail matrix, both derived from epidermal keratinocytes. The dermis supports follicles with connective tissue and vessels but doesn't grow them. The hypodermis (subcutaneous tissue) provides fat and anchoring, not growth. The epidermis's role in generating these keratinized appendages, through cell division in basal layers, makes it the correct layer, per integumentary development.