- The process of milk production. Human milk is secreted by the mammary glands, which are located within the fatty tissue of the breast. The hormone oxytocin is produced in response to the birth of a new baby, and it both stimulates uterine contractions and begins the lactation process. For the first few hours of nursing, a special fluid called colostrum is delivered, which is especially high in nutrients, fats, and antibodies to protect the newborn from infection. Thereafter the amount of milk produced is controlled primarily by the hormone prolactin, which is produced in response to the length of time the infant nurses at the breast. See also breastfeeding.
* * *1. Production of milk. 2. Period following birth during which milk is secreted in the breasts. [L. lactatio, suckle]
* * *lac·ta·tion lak-'tā-shən n1) the secretion and yielding of milk by the mammary gland2) one complete period of lactation extending from about the time of parturition to weaninglac·ta·tion·al -shən-əl adjlac·ta·tion·al·ly -ē adv
* * *n.the secretion of milk by the mammary gland of the breasts, which usually begins at the end of pregnancy. A fluid called colostrum is secreted before the milk is produced; both secretions are released in response to the sucking action of the infant on the nipple. Lactation is controlled by hormones (see prolactin, oxytocin); it stops when the baby is no longer fed at the breast.
* * *lac·ta·tion (lak-taґshən) [L. lactatio, from lactare to suckle] 1. the secretion of milk. 2. the period of secretion of milk.
Medical dictionary. 2011.