Final answer:
Lactation is the process by which milk is synthesized and secreted from the mammary glands. The composition of breast milk changes during the first days of lactation and in a single feeding, providing essential nutrients and immune protection for the newborn. Breastfeeding is an example of positive feedback.
Step-by-step explanation:
Lactation is the process by which milk is synthesized and secreted from the mammary glands of the postpartum female breast in response to an infant sucking at the nipple. Breast milk provides ideal nutrition and passive immunity for the infant, encourages mild uterine contractions to return the uterus to its pre-pregnancy size (i.e., involution), and induces a substantial metabolic increase in the mother, consuming the fat reserves stored during pregnancy.
During breastfeeding, the stimulus of the baby sucking on the nipple increases the amount of milk produced by the mother. This is an example of positive feedback. The milk production regulation mechanism described here allows the mother's body to respond to the baby's demand and provide enough milk for the infant's needs.
The composition of breast milk changes during the first days of lactation and in the course of a single feeding. In the first few days after delivery, the mother produces colostrum, a yellowish fluid rich in protein and immunoglobulins that provide essential nutrients and immune protection for the newborn. As the days go by, the composition of breast milk transitions to mature milk, which contains the right balance of carbohydrates, fats, proteins, and vitamins to support the baby's growth and development.