Mammary glands are a type of gland that is found in the breasts of mammals. These glands are responsible for producing milk for nursing young. The mammary gland is composed of two parts: the lobules, which produce milk, and the ducts, which carry the milk to the nipple. The mammary gland is surrounded by fat and connective tissue.
Mammary glands develop during puberty in response to hormones, such as estrogen and progesterone. In pregnant women, mammary glands enlarge and produce milk in preparation for nursing. After childbirth, mammary glands continue to produce milk until weaning occurs.
Milk production begins during pregnancy as the hormones estrogen and progesterone stimulate the growth of the mammary gland. After birth, the hormone prolactin stimulates milk production. Mammary glands are capable of producing large amounts of milk; for example, a cow can produce up to 50 liters (about 13 gallons) of milk per day!
Mammary glands are an important part of the reproductive system and play a vital role in bonding between mother and child. In addition, they provide essential nutrients for infants and help protect against infection.

Disambiguation
The term “mammary gland” can also refer to the sweat glands in the breast area. These glands are not involved in milk production. Moreover, while the term “mammary gland” is most often used to refer to the glands in breasts, it can also refer to any gland in mammals that produces milk. For example, some species of bats have mammary glands on their backs that they use to feed their young.
Other Related Terms
There are several terms that are closely associated with mammary glands:
Lactation: This is the process of producing milk from the mammary glands. Lactation can occur during pregnancy and after birth.
Nursing: This is when an infant drinks milk from its mother’s breast. Nursing helps infants get nutrition and antibodies that help them fight disease.
Weaning: This is when an infant starts to eat solid food and drinks less milk. Weaning typically occurs around 6 months old but can happen sooner or later depending on the child and family’s preferences.
This image shows how often the term ‘Mammary Glands’ is used in relation to other, similar birth terms:

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