Which of the following word pairs is (are) appropriate?

Correct Answer: C

Rationale: The integumentary system is a complex structure that serves as the body's outer covering, including skin, hair, nails, and glands. While 'iatcgument-gland' appears to be a typo and does not make sense in this context, 'integument-tissue' refers to the skin as a type of tissue, which is accurate but incomplete. The term 'integument-organ' is the most appropriate because the integumentary system is classified as an organ system in anatomy, encompassing multiple tissues (epithelial, connective, etc.) working together. 'All the above' would only be correct if all pairs were valid, but the first option is not, likely due to a transcription error. The focus on the integument as an organ aligns with its role in protection, temperature regulation, and sensory reception, making it more than just a tissue or a gland-related structure. Thus, the precise pairing is one that recognizes its status as an organ, reflecting its integrated functions and anatomical significance.

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.

Correct Answer: C

Rationale: The skin plays a unique role in vitamin production, specifically synthesizing vitamin D when exposed to ultraviolet (UV) light from the sun. This process occurs in the epidermis, where UV rays convert 7-dehydrocholesterol into previtamin D3, which then becomes vitamin D3 (cholecalciferol). This vitamin is crucial for calcium absorption and bone health. Vitamin A, essential for skin cell development, is not synthesized by the skin but obtained through diet (e.g., from beta-carotene). Vitamin C, an antioxidant vital for collagen synthesis, is also diet-derived, not produced in the skin. Vitamin E, another antioxidant protecting skin cells, is similarly acquired through food or supplements, not manufactured by the integument. The skin's ability to produce vitamin D distinguishes it from other vitamins, an evolutionary adaptation to ensure adequate levels in sunlight-exposed populations. This synthesis is regulated by exposure time and skin pigmentation, with darker skin requiring more UV exposure due to melanin's filtering effect. Thus, vitamin D is the only vitamin the skin synthesizes, aligning with its physiological role.