Human milk is nature's greatest mystery. This is a special fluid produced in a woman's body after childbirth from the mammary glands - the breast. In the first months of life, an infant receives nutrition that most closely matches the nutritional needs it needs. In addition, mother's milk contains hormones, immune defense factors and beneficial microflora designed to populate the sterile niche of the newborn's intestines.
Breast milk is produced in the paired mammary gland, which is a modified sweat gland. In humans, both women and men have mammary glands, but they differ only in the degree of their development, their structure is identical. In a sexually mature woman, the mammary gland consists of two spherical formations on the chest, in the very center of which is the areola - a pigmented rounded area with a nipple at the apex, into which all ducts of the gland open.
The body of the breast is surrounded by a thick layer of fat and consists of 15–20 separate lobes that are located around the nipple. Connective tissue is concentrated between the lobes of the breast. In turn, each large lobe consists of a combination of large and small lobules, and the microscopic structure shows that the lobules are, like lungs, from alveoli 0.05–0.07 mm each.
Formation of female lactation
The mammary gland is hormone dependent. Cyclic changes in her occur before pregnancy, but during pregnancy the most significant transformations occur. So, under the influence of the hormones prolactin and estrogen, the areola darkens, the breast weight increases to 300-900 g (compared to the “pre-pregnant” weight of 150-200 g), its size becomes larger, the first milk gradually begins to be released in the lobules and descend to the nipple - “colostrum". Colostrum during pregnancy is a white-yellow oily substance and is secreted in response to irritation in the nipple area.
By the time it is approaching due date, colostrum becomes more and more liquid and similar to the milk that everyone is used to seeing. In the first days after childbirth, "transitional milk" is excreted. This milk is much thicker and yellower than normal human breast milk. On the third or fifth day after childbirth, real "mature milk" comes. It is white or bluish-white in color with a sweetish smell and taste. Its fat content is about 4%.
During one feeding, the milk also changes: the “front” milk, which the baby sucks out first, has a more liquid consistency and white color, then, already in an almost empty breast, the baby with difficulty sucks out the “back” - denser milk, with yellowish tinge, saturated with fats. If the child gets drunk with the front milk, he eats up the back milk. At the end of lactation, the mammary gland will decrease again, but will be larger than its original size.