Mammary gland

A mammary gland is an <a href="/facts/Exocrine_gland/svLWvb83">exocrine gland</a> that produces <a href="/facts/Milk/wDJBUHvy">milk</a> in <a href="/facts/Human/rlcTENsr">humans</a> and other <a href="/facts/Mammal/phSwTzBo">mammals</a>. Mammals get their name from the Latin word mamma, "breast". The mammary glands are arranged in <a href="/facts/Organ_(anatomy)/FUYsLaxz">organs</a> such as the <a href="/facts/Breast/UBvcKAjy">breasts</a> in primates (for example, humans and chimpanzees), the <a href="/facts/Udder/4q4BvJ2F">udder</a> in <a href="/facts/Ruminant/tTcBMxk4">ruminants</a> (for example, cows, goats, sheep, and deer), and the dugs of other animals (for example, dogs and cats) to feed young <a href="/facts/Offspring/v7LD4qBl">offspring</a>. <a href="/facts/Galactorrhea/tB5rDh0B">Lactorrhea</a>, the occasional production of milk by the glands, can occur in any mammal, but in most mammals, <a href="/facts/Lactation/0w1HoW27">lactation</a>, the production of enough milk for nursing, occurs only in <a href="/facts/Phenotype/vxWXKGLj">phenotypic</a> <a href="/facts/Female/hk4wM9y1">females</a> who have <a href="/facts/Gestation/QKgkykw5">gestated</a> in recent months or years. It is directed by hormonal guidance from <a href="/facts/Sex_steroid/mI6bkHII">sex steroids</a>. In a few mammalian species, <a href="/facts/Male_lactation/3coPvXK5">male lactation</a> can occur. With humans, male lactation can occur only under specific circumstances.
Mammals are divided into 3 groups: <a href="/facts/Monotreme/fLMJM4JU">monotremes</a>, <a href="/facts/Metatheria/g4a84l76">metatherians</a>, and <a href="/facts/Eutheria/3fPKIKxx">eutherians</a>. In the case of monotremes, their mammary glands are modified <a href="/facts/Sebaceous_glands/HKMXmv1Y">sebaceous glands</a> and without nipples. 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 <a href="/facts/Udder/4q4BvJ2F">udders</a>. 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 <a href="/facts/Teat/GLuGdzSI">teat</a>) 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.

Mammary gland open-in-new

Mammary gland