Breast
Breast, one of a pair of glandular organs in mammals that secrete milk for newborns and infants. Also known as a mammary gland , particularly in nonhuman mammals, the breast is unique to mammals and is not found in any other type of animal. In humans, the female breast has a distinctive rounded shape while the male breast remains flat and undeveloped. Only mature females can produce milk, which is rich in nutrients, antibodies, and other substances that aid in a baby’s growth and development. The surface of a human breast has a circular, pigmented area in the center called the areola. The nipple, a rounded protruding structure, lies in the center of the areola. In mature women the breast contains a collection of 10 to 15 tubes, called ducts, that connect to the nipple. These ducts branch out from the nipple into the interior of the breast, ending in clusters of rounded cells, called lobules, that produce the milk. In addition to the structures directly connected with the production a