Which of the following is an example of an exocrine gland?

• A. Sweat glands
• B. Endocrine glands
• C. Adrenal gland
• D. Thyroid gland

Answer: (A)

Exocrine glands secrete their products through ducts to an external or body surface. Sweat glands fit this pattern because they produce sweat and release it via ducts to the skin surface. In contrast, glands like the adrenal and thyroid are endocrine; they release hormones directly into the bloodstream without ducts. (Note: some organs have both components, such as the pancreas, which has exocrine digestive enzyme portions and endocrine hormone-producing islets, but the example here clearly demonstrates exocrine secretion through a duct.)