Mammary glands

Mammary glands, special glands present in mammals, situated ventrally in pairs, modified in females to produce and secrete milk to nourish offspring. The milk, secreted by cells lining the small compartments, or lobules, that make up each gland, then travels from the lobules along ducts to the nipple, where it is emptied. Mammary glands, which develop in female humans at the onset of adolescence, remain undeveloped in male mammals.