Each breast has 15 to 20 sections, or lobes, that surround the nipple in a radial manner, like spokes on a wheel. Inside these lobes are smaller sections, called lobules. At the end of each lobule are tiny "bulbs" that produce milk. These structures are linked together by small tubes called ducts, which carry milk to the nipples.
The breasts are specialised organs, which are located on the anterior chest wall. The female breast is more developed than the male breast, as their primary function is to produce milk for nutrition of the infant and baby. There are lots of glands in our breasts, which grow and develop during puberty and maturation. Female hormones such as oestrogen and progesterone are important in promoting growth and changes that occur in the breast, especially during pregnancy and the menstrual cycle. Lying in a superficial layer of our skin above our chest muscles, the mammary glands in our breast drain via many ducts to our nipples. There is a dark, circular layer around the nipple , called the areola. It is important for women to understand the normal anatomy and function of their breasts so that any abnormalities can be detected and treated.
The breast is a highly complex part of the human body. It goes through many changes over a lifetime — from birth, puberty, pregnancy and breastfeeding, right through to menopause. Breast tissue extends from the collarbone, to lower ribs, sternum breastbone and armpit.
The breast is one of two prominences located on the upper ventral region of the torso of primates. In females, it serves as the mammary gland , which produces and secretes milk to feed infants. At puberty , estrogens , in conjunction with growth hormone , cause breast development in female humans and to a much lesser extent in other primates. Breast development in other primate females generally only occurs with pregnancy. Subcutaneous fat covers and envelops a network of ducts that converge on the nipple , and these tissues give the breast its size and shape.