Which gland is primarily responsible for milk production?

• A. Mammary glands
• B. Sebaceous glands
• C. Apocrine sweat glands
• D. Eccrine glands

Answer: (A)

Milk production is carried out by the mammary glands, which are specialized exocrine glands derived from skin. They contain secretory units called alveoli lined by lactocytes that synthesize and release milk components (proteins, fats, lactose) into the alveolar lumen. The alveoli drain into ducts that converge toward the nipple, where milk is stored and transported to the infant.

Hormonal control shapes this process: prolactin from the pituitary drives milk synthesis, while oxytocin causes the myoepithelial cells around the alveoli and ducts to contract, pushing milk out during let-down. During pregnancy, estrogen and progesterone promote gland development, and after birth their withdrawal allows prolactin to drive lactation.

Other options are skin glands not involved in milk production—sebaceous glands secrete sebum, while apocrine and eccrine glands produce different forms of sweat.