(Posted:29-Jul-2015)

The breast, begin to develop at puberty.This development is stimulated by the estrogens of the monthly female sexual cycle; estrogen growth of the breasts's mammary gland and the deposition of fat to give the breasts mass. In addition,far greater growth occurs duringvthe high estrogen state of pregnancy and only then does the glandular tissue become completely for the production the of milk. Estrogens Stimulate Growth of the Ductal system of the Breast. Projesteron is Required for Full Development of the Lobule-Alveolar System. Prolactin promots lactation: This hormone secreted is secreted by mother's anterior pituitary gland and its concentration in her blood rises from feefth week of pregnancy untill birth of the baby. In addition the placenta secretes large quantities of human chorionic gonadotropin which has lactogenic property,thus supporting the prolactin from the mother's pituitary during pregnancy.The fluid secreted during the last few days before and the first few days after parturition called colostrum. Immediatly after the baby is born,the sudden loss of both estrogen and progesteron secretion from the placenta allows the lactogenic effect of prolactin from the mother's pituitary gland to assume its natural milk promoting role and over the next 1 to 7 days,the breast begin the secrete copious quantities of milk instead of colostrum. Milk is secreted continuously into the alveoli of the breast,but the milk must be ejected from the alveoli into the ducts before the baby can obtain it & this is caused by posterior pituitary hormone oxytocin.