Structure of the breast, its development

To understand the structure and origin of mammary glands will help anatomy. The mammary gland is a modified apocrine sweat gland, developed from the ectoderm. In humans, the development of mammary glands occurs during the sixth week of intrauterine life. In the area of mammary glands, the skin is thin, tender, contains hair follicles, sweat and sebaceous glands. In the mammary gland, there are many nerve fibers from the brachial and cervical plexuses and intercostal nerves. The gland's body has a disk-shaped convex shape, the color is usually pale pink, a dense consistency, the average diameter at the base is 10-13 cm. The mammary glands in girls have an average weight of 150-200 g, and in the lactation period - 400-900 g. Most healthy young women have glandular hemispheres and is elastic. The growth of the breast, size, shape and position have individual characteristics and characteristics.

Structure of the breast and its anatomy

Female mammary glands consist of a variety of cells that produce milk, which are collected in lobules. From each individual lobule flows the lactate flow, and all lobules are combined into segments that have an excretory duct, in which all terminal small ducts are combined.

The shares are located relatively to the nipple radially and are separated from each other by a fatty tissue. Each part of the gland has a conical shape with a vertex at the nipple, where the excretory duct opens. The ducts in front of the nipple expand, forming thus lacteal sinuses. The educated area around the nipple is called the areola, and the small elevations on it are the sweat glands. The structure of the breast in women differs from the structure of the male gland.

The growth of the mammary glands is due to prolactin (hormone of the anterior lobe of the pituitary gland) and ovarian hormones. Thanks to prolactin comes lactation. In the first half of pregnancy, the breast increases in size, and in the second half, the secretory activity of epithelial cells increases, which consist of alveoli. At the end of pregnancy and within a few days after birth, secretion increases and a yellowish, thick nutrient fluid called colostrum is produced. Then there is a change in the secretion, it acquires a more liquid consistency and releases milk. By the end of the feeding period, the production of milk is reduced and stops until the next pregnancy.

Development of mammary glands in girls occurs during puberty at the age of 10-15 years. The process begins with the growth of the nipple and the nasal areola, then the growth of the mammary gland as a whole begins. The breast of women grows for a long time and the breast size is fixed permanently only after the baby is fed. The penultimate stage of breast growth reaches at the age of 15-17 years.

The mammary gland is a labile organ, just like the uterus, subject to cyclic changes. Before the beginning of menstruation, proliferation of glands occurs, the tissues swell, the gland becomes swollen and friable. After the end of menstruation, these manifestations disappear. According to the age periods, the mammary gland is divided into 4 types.

1. The gland of a girl or woman is 20-25 years old. The mammary gland has a homogeneous structure, the milk ducts are invisible, the width of the premammary space is not more than 5 mm.
2. Iron in women aged 25 to 40 years is functionally active. Its milky passage is lined with epithelium, constantly expanding, on the walls appear twigs with terminal secretory vesicles. The structure of the glands changes in connection with the cyclic changes.
3. Breast in the period of menopause. In the premenopausal glandular tissue is dispersed in the form of small islets in the glandular triangle, which are separated by fields from adipose tissue. With age, the number of glandular parenchyma decreases, the mammary gland becomes broadly pendulous. Fibrous tissue atrophies.
4. Mammary gland of a woman in the postmenopausal period. In the period of menopause changes in the mammary gland become irreversible, glandular tissue completely disappears, it is replaced by fatty tissue.

As mentioned above, the structure of the breast depends on the age, the level of development of the genital organs, the phase of the menstrual cycle of the woman, the hormonal status, the period of pregnancy and lactation. Age is the main factor that determines the structural type of glands. But, nevertheless, there is an individual variability in the reduction and development of glandular elements, which are determined by alimentary, endocrine and other factors.