The breast generally refers to the chest, however, more specifically, to the mammary gland. The mammary gland is a milk producing gland comprised largely of fat. Within the mammary gland is a complex network of branching ducts. The ducts exit from sac-like structures called lobules, which can produce milk in females. The darkened area around the nipple is called the areola. Common medical concerns in regard to the breast include breast lumps, breast cysts, breast cancer, and breast infections.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
The breast generally refers to the front of the chest
specifically to the mammary gland.
(The word "mammary" comes from "mamma," the Greek and Latin word
for the breast, which derives from the cry "mama" uttered by infants
and young children, sometimes meaning "I want to feed at the
How is the mammary gland designed?
The mammary gland is a milk-producing structure that is composed
largely of fat cells (cells capable of storing fat). The fat deposits
are laid down in the breast under the influence of the female hormone estrogen. Just as
the surge of estrogens at adolescence encourages this process,
androgens, such as testosterone, discourage it.
Within the mammary gland there is a complex network of
branching ducts (tubes or channels). These ducts exit from sac-like
structures called lobules.
The lobules in the breast are the glands that can produce milk in
females when they receive the appropriate hormonal stimulation.
The breast ducts transport milk from the lobules out to the
nipple. The milk exits the ducts from the breast at the nipple.
Picture of the anatomy of the breast
How are human breasts different from those of other primates?
Human breasts function somewhat differently than those
of other primates. In other primates, the breasts grow only when the female is
producing milk (lactating). When the non-human primate female has weaned her
young, her breasts flatten back down. In humans, the breasts develop at
adolescence usually well before any
pregnancy has occurred and the breasts stay
enlarged throughout the remainder of life.
During pregnancy the breasts grow further. This growth is
much more uniform than that at adolescence. The breasts of women with small
breasts tend to grow about as much during pregnancy as those of women with large
breasts. The amount of milk-producing tissue is
essentially the same. This is the reason that
when milk production begins, small-breasted women produce as much milk as
do large-breasted women.