Mammary gland

Cross-section of the human mammary gland. 1. Chest wall

2. Pectoralis muscles

3. Lobules

4. Nipple

5. Areola

6. Milk duct

7. Fatty tissue

8. Skin
Light micrograph of a human proliferating mammary gland during estrous cycle. Sprouting gland tissue can be seen in the upper left field (haematoxylin eosin staining)
Cross section of the breast of a human female

Exocrine gland in humans and other mammals that produces milk to feed young offspring.

- Mammary gland

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Sex of an organism that produces the large non-motile ova (egg cells), the type of gamete (sex cell) that fuses with the male gamete during sexual reproduction.

The symbol of the Roman goddess Venus is used to represent the female sex in biology. It also stands for the planet Venus and is the alchemical symbol for copper.
"fæmnan," an Old English word for 'female'
Photograph of an adult female human, with an adult male for comparison. Note that both models have partially shaved body hair to show anatomy; e.g. clean-shaven pubic regions.

Female characteristics vary between different species with some species having pronounced female characteristics, such as the presence of pronounced mammary glands in mammals.


Teats protruding from the udder of a cow
Part of a milking device that fits over the teats of a cow.

A teat is the projection from the mammary glands of mammals from which milk flows or is ejected for the purpose of feeding young.

Sweat gland

A cross-section of the human skin, with the sweat gland labeled at the bottom
Body of a sweat gland cut in various directions
Human sweat gland pores on the ridges of a finger pad
In apocrine secretion (pictured), portions of the cell are pinched off and later disintegrate.

Ceruminous glands (which produce ear wax), mammary glands (which produce milk), and ciliary glands in the eyelids are modified apocrine sweat glands.


A glass of cow milk
Cows in a rotary milking parlor
Breastfeeding to provide a mother's milk
A goat kid feeding on its mother's milk
The Holstein Friesian cow is the dominant breed in industrialized dairy farms today
A bowl of milk for the shaman rite; Buryatia, Russia
Drinking milk in Germany in 1932
Preserved Express Dairies three-axle milk tank wagon at the Didcot Railway Centre, based on an SR chassis
Milk transportation in Salem, Tamil Nadu
Industralized milk.
Modern dairy farm in Norway
Butterfat is a triglyceride (fat) formed from fatty acids such as myristic, palmitic, and oleic acids.
A simplified representation of a lactose molecule being broken down into glucose (2) and galactose (1)
Milk products and productions relationships (click to enlarge)
A milking machine in action
Glass milk bottle used for home delivery service in the UK
Returning reusable glass milk bottles, used for home delivery service in the UK
Vendors in Amritsar,India transporting milk in gagar, 2019
Milk in different packets
Four liter bagged milk in Quebec, Canada
The milk section in a Swedish grocery store
A primary school child in England drinking milk out of a glass bottle with a straw
A glass bottle of non-homogenized, organic, local milk from the US state of California. American milk bottles are generally rectangular in shape.
A rectangular milk jug design used by Costco and Sam's Club stores in the United States which allows for stacking and display of filled containers rather than being shipped to the store in milk crates and manual loading into a freezer display rack
Yakult, a probiotic milk-like product made by fermenting a mixture of skimmed milk with a special strain of the bacterium Lactobacillus casei Shirota
Gourd used by Kalenjins to prepare a local version of fermented milk called mursik
Steamed milk is used in a variety of espresso-based coffee beverages.
Hindu Abhisheka ritual in Agara, Bangalore Rural District, Karnataka
A milk and rose-petal bath at a spa in Thailand

Milk is a nutrient-rich liquid food produced by the mammary glands of mammals.


The original synapsid skull structure contains one temporal opening behind the orbitals, in a fairly low position on the skull (lower right in this image). This opening might have assisted in containing the jaw muscles of these organisms which could have increased their biting strength.
Restoration of Juramaia sinensis, the oldest known Eutherian (160 M.Y.A.)
Fossil of Thrinaxodon at the National Museum of Natural History
Raccoon lungs being inflated manually
Mammal skin: 1 — hair, 2 — epidermis, 3 — sebaceous gland, 4 — Arrector pili muscle, 5 — dermis, 6 — hair follicle, 7 — sweat gland, 8 (not labeled, the bottom layer) — hypodermis, showing round adipocytes
Bovine kidney
A diagram of ultrasonic signals emitted by a bat, and the echo from a nearby object
Porcupines use their spines for defense.
A leopard's disruptively colored coat provides camouflage for this ambush predator.
Goat kids stay with their mother until they are weaned.
Matschie's tree-kangaroo with young in pouch
Running gait. Photographs by Eadweard Muybridge, 1887.
Gibbons are very good brachiators because their elongated limbs enable them to easily swing and grasp on to branches.
Vervet monkeys use at least four distinct alarm calls for different predators.
A bonobo fishing for termites with a stick
Female elephants live in stable groups, along with their offspring.
Red kangaroos "boxing" for dominance
Upper Paleolithic cave painting of a variety of large mammals, Lascaux, c. 17,300 years old
Cattle have been kept for milk for thousands of years.
Biodiversity of large mammal species per continent before and after humans arrived there
Sexual dimorphism in aurochs, the extinct wild ancestor of cattle.

Mammals (from Latin mamma, 'breast') are a group of vertebrates constituting the class Mammalia, characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones.


Raised region of tissue on the surface of the breast from which, in females, milk leaves the breast through the lactiferous ducts to feed an infant.

A nipple, areola and breast of a female human
A human male nipple
Infant latched on to nipple.
Silicone teat or nipple, used for bottle feeding.
Duplessis's portrait of a semi-topless Marie Thérèse Louise of Savoy dates from 18th-century France.
A Namibian woman

The physiological purpose of nipples is to deliver milk, produced in the female mammary glands during lactation, to an infant.


Bovine colostrum and spray-dried colostrum powder
On the left is milk expressed on day 4 of lactation, and on the right is breastmilk expressed on day 8. Colostrum gives the milk a yellow hue.
Solidified colostrum in a sweet stall, Salem, Tamil Nadu.
Molozyvo—a traditional dish of Ukrainian cuisine. It is a sweet cheese made of cow colostrum.

Colostrum (known colloquially as beestings, bisnings or first milk) is the first form of milk produced by the mammary glands of mammals (including humans) immediately following delivery of the newborn.

Lactiferous duct

The Breast: cross-section scheme of the mammary gland. 1. Chest wall

2. Pectoralis muscles,

3. Lobules

4. Nipple

5. Areola and Montgomery glands

6. Milk duct

7. Fatty tissue

8. Skin

Lactiferous ducts are ducts that converge and form a branched system connecting the nipple to the lobules of the mammary gland.



A representation of the 3D structure of the protein myoglobin showing turquoise α-helices. This protein was the first to have its structure solved by X-ray crystallography. Toward the right-center among the coils, a prosthetic group called a heme group (shown in gray) with a bound oxygen molecule (red).

It stimulates the mammary glands to produce milk (lactation): increased serum concentrations of prolactin during pregnancy cause enlargement of the mammary glands and prepare for milk production, which normally starts when levels of progesterone fall by the end of pregnancy and a suckling stimulus is present.

Lobe (anatomy)

Clear anatomical division or extension of an organ that can be determined without the use of a microscope at the gross anatomy level.

Visceral surface of the liver showing the four lobes
Lobules of the mammary glands.

the lobules of the mammary gland