What makes up breast milk? Is it related to endocrine system?

After giving birth, a woman's breasts will naturally secrete milk. This is a very common physiological process. However, friends who don't know much about this want to know how breast milk is produced. This is because there is no milk in the human body and no container to store milk. In fact, this is a normal physiological change regulated by the endocrine nerves. It is mainly related to the development of the mammary glands, so you need to understand it in your daily life.

Milk production includes two processes: lactation and milk ejection.

Both are regulated by neuroendocrine, among which the pituitary gland in the human body is the most important endocrine gland involved in lactation and milk ejection. During pregnancy, estrogen and progesterone produced by the ovaries and placenta stimulate the development of the alveoli and mammary ducts, but have an inhibitory effect on prolactin secreted by the anterior pituitary gland, so the breasts do not secrete milk during pregnancy. When the fetus is delivered and the placenta is separated, the levels of estrogen and progesterone drop sharply, and the pituitary gland begins to secrete prolactin, which prompts the alveoli to secrete milk. At this time, the mother begins to feel breast fullness, but the milk will not be discharged automatically. For breastfeeding to be successful, it must be completed through the lactation reflex and milk ejection reflex.

How are these two reflexes established? The key lies in the stimulation of the baby sucking the nipple. When a baby sucks the nipple for the first time after birth, sucking stimulates the rich sensory nerve endings in the nipple and areola area, transmitting the stimulation impulse to the posterior pituitary gland, causing it to secrete oxytocin. This hormone circulates through the blood and acts on the myoepithelial cells surrounding the mammary ducts, causing them to contract and discharge milk, forming a milk ejection reflex. The sucking stimulation causes another part of the nerve impulse to be transmitted directly to the anterior pituitary gland, causing it to secrete prolactin, stimulating the alveoli to continue to secrete milk. Generally, within a few minutes of each sucking, the amount of prolactin in the blood will increase 10 times, preparing the baby for the next breastfeeding. Therefore, as long as the baby keeps sucking, the milk will continue to come.

If the baby is not breastfed in time after delivery, the mother's nipples will not receive sucking stimulation, the above two reflexes cannot be established, milk cannot be discharged, continued lactation will be inhibited, and milk production will also be blocked. Therefore, the stimulation of the baby sucking the nipple is the key to promoting milk production. The more sucking stimulation, the more milk will be produced.