| Mammary gland | |
|---|---|
 Cross-section of the human mammary gland. | |
| Details | |
| Precursor | Mesoderm (blood vessels and connective tissue) Ectoderm[3] (cellular elements) |
| Artery | Internal thoracic artery Lateral thoracic artery[1] |
| Vein | Internal thoracic vein Axillary vein[1] |
| Nerve | Supraclavicular nerves Intercostal nerves[2] (lateral and medial branches) |
| Lymph | Pectoral axillary lymph nodes[1] |
| Identifiers | |
| TA98 | A16.0.02.006 |
| TA2 | 7099 |
| FMA | 60088 |
| Anatomical terminology | |
A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word mamma, "breast". The mammary glands are arranged in organs such as the breasts in primates (for example, humans and chimpanzees), the udder in ruminants (for example, cows, goats, sheep, and deer), and the dugs of other animals (for example, dogs and cats). Lactorrhea, the occasional production of milk by the glands, can occur in any mammal, but in most mammals, lactation, the production of enough milk for nursing, occurs only in phenotypic females who have gestated in recent months or years. It is directed by hormonal guidance from sex steroids. In a few mammalian species, male lactation can occur. With humans, male lactation can occur only under specific circumstances.
Mammals are divided into 3 groups: prototherians, metatherians, and eutherians. In the case of prototherians, both males and females have functional mammary glands, but their mammary glands are without nipples. These mammary glands are modified sebaceous glands. Concerning most metatherians and eutherians, only females have functional mammary glands, with the exception of some bat species. Their mammary glands can be termed as breasts or udders. In the case of breasts, each mammary gland has its own nipple (e.g., human mammary glands). In the case of udders, pairs of mammary glands comprise a single mass, with more than one nipple (or teat) hanging from it. For instance, cows and buffalo udders have two pairs of mammary glands and four teats, whereas sheep and goat udders have one pair of mammary glands with two teats protruding from the udder. Each gland produces milk for a single teat. These mammary glands are evolutionarily derived from sweat glands.
- ^ a b c Macéa, José Rafael; Fregnani, José Humberto Tavares Guerreiro (1 December 2006). "Anatomy of the Thoracic Wall, Axilla and Breast" (PDF). International Journal of Morphology. 24 (4). doi:10.4067/S0717-95022006000500030.
- ^ Lawrence, Ruth A.; Lawrence, Robert M. (30 September 2010). Breastfeeding: A Guide for the Medical Profession (7th ed.). Maryland Heights, Maryland: Mosby/Elsevier. p. 54. ISBN 9781437735901.
- ^ Gray, Henry (1918). Anatomy of the Human Body.