Which describes a primary function of excretion in the skin?

Which describes a primary function of excretion in the skin?

• A. Expels waste products, toxins, pollutants, and dead skin cells; helps regulate temperature by excreting sweat from the sweat glands
• B. Produces sebum
• C. Stores fat
• D. Synthesizes vitamin D

Answer: (A)

Excretion in the skin primarily involves removing wastes from the body through sweat and surface shedding. Sweat glands expel water, salts, and small amounts of waste products like urea; as sweat evaporates, it cools the body, helping regulate temperature. The phrase about dead skin cells reflects the skin’s broader role in eliminating surface debris as part of normal turnover, but the main excretory action is sweating. The other options describe different skin functions: producing sebum lubricates and protects the skin, storing fat occurs in the underlying subcutaneous tissue, and synthesizing vitamin D is a metabolic process activated by UV exposure, not excretion.

Excretion in the skin primarily involves removing wastes from the body through sweat and surface shedding. Sweat glands expel water, salts, and small amounts of waste products like urea; as sweat evaporates, it cools the body, helping regulate temperature. The phrase about dead skin cells reflects the skin’s broader role in eliminating surface debris as part of normal turnover, but the main excretory action is sweating. The other options describe different skin functions: producing sebum lubricates and protects the skin, storing fat occurs in the underlying subcutaneous tissue, and synthesizing vitamin D is a metabolic process activated by UV exposure, not excretion.