What are the two main types of epithelial glands or down-growths?

• A. Exocrine and Endocrine glands
• B. Tubular and Acinar glands
• C. Merocrine and Holocrine glands
• D. Goblet cells and sweat glands

Answer: (A)

Glandular tissue formed from epithelial down-growths is classified by where its secretions go. If a duct connects the gland to a surface or lumen and its secretions exit through that duct, the gland is exocrine. If there’s no duct and the secretions are released into the bloodstream, the gland is endocrine. This duct-based distinction is what defines the two main types, reflecting how development shapes function: exocrine glands maintain a duct to the surface, while endocrine glands become ductless and release hormones into blood vessels. For context, sweat glands and goblet cells are classic exocrine examples, while endocrine glands include the thyroid, adrenal, and pituitary. The other terms describe more specific features (shape of the secretory unit, secretion mechanism) and thus don’t define the primary division.