Mammary glands are found in a female body that has achieved sexual maturity. They are sweat glands that are composed of mammary alveoli and the necessary ducts. Though most people think that the mammary glands are part of the reproductive system, they are not. They are actually a part of the integumentary system. But, they are linked to the reproductive system because they help the body in attracting a mate, and they assist in lactation after pregnancy. The size and the shape of mammary glands differ, based on age, race, body fat and pregnancy.
During puberty, estrogen releases hormones that control the development and the functions of the mammary glands. Hypotrophy of the glands occur among pregnant and nursing women. Atrophy of the breasts normally happens after the female body has gone through menopause
Overlapping the pectoral muscle and the oblique muscles, the breasts are located over the second to the sixth ribs. The sternum’s lateral margin allows a gap between the ribs and the edge of each breast. Each of the two glands also trace a route along the anterior margin of the axilla. They barely hit the axillary vessels and travel up to the axilla. Breast cancer develops because of the lymphatic drainage of the axillary process.
The mammary glands are amde up of 15 to 29 lobes with each lobe possessing a duct that leads to the exterior of the body. The lobes are segregated by adipose tissues. These tissues manage the size and the shape of the breats, but they don’t predetermine the ability to suckle a baby. Within each lobe are lobules, and within the lobules are mammary alveoli. The mammary alveoli produces the milk that a lactating female secretes. The breasts are supported by suspensory ligaments that are connected between the lobules and travel into the fascia that go beyond the pectoral muscles. The mammary alveoli secrete the milk into a network of mammary ducts. This network is also made up of lactiferous ducts. The lactiferous ducts expand into the body’s lumen beside each nipple. The milk is kept in place by the lactiferous sinuses, and when pressure is exerted, the milk is expelled through the tip of the nipple into the outside of the body.
The nipples are made up of erectile tissues that give them a cylindrical shape. Areola is the circular portion of the nipple that features a different color. Under the areola is a bumpy surface that is created by sebaceous areolar glands. To keep the nipple supple, the areolar glands continually secrete fluids (whether the female is lactating or not). The areola’s color depends on the color of the rest of the body, though the pigment and the tint may be slightly different. When the body is gestating, the areola darkens and enlarges. That is because the nursing child would find it easier.
Blood flow to the nipples and the rest of the mammary glands is provided by the internal thoracic arterial branches. They enter the mammary glands in between he second, third and fourth intercostal margins. The spaces are found lateral to the sternum, and allows the entry of blood into the mammary artery. The veins are found next to the arteries. When a woman is pregnant or lactating (sometimes, even when she’s not), a superificial venous plexus is evident on the surface of the mammary skin.
Innervation to the breasts by way of sensory somatic neurons is supplied by the fourth, fifth and sixth thoracic nerves. The somatic neurons come from the thoracic nerves’ anterior and lateral branches. A sensory stimulus triggers the release of breast milk.