Mammary glands —mammary glands in mammals) are paired glands of external secretion that are part of the mammalian reproductive system and are responsible for the production of milk — a nutrient fluid for feeding offspring (lactation). They are located on the anterior (ventral) surface of the mammalian body. In humans, they are located on the front surface of the chest.
In male mammals, they are usually in an undeveloped, rudimentary state, and in females they develop during puberty and acquire the ability to function with the onset of puberty together with other organs of the female reproductive system. The beginning of milk production by the glands is regulated by hormones of the endocrine glands associated with the end of pregnancy and the birth of offspring.
In female representatives of the species homo sapiens, mammary glands usually increase significantly in size during puberty (English mammoplasia), and this, along with other differences in body structure, visually distinguishes them from men.
Mammary glands are a distinctive feature of representatives of the mammalian class, and the very name of mammals shows that only these representatives of vertebrates (unlike birds or fish, as well as invertebrates) have such glands and feed their offspring with their secret.
Mammary glands are modified sweat glands, and the mammary glands of primroses are almost indistinguishable from sweat glands in their structure. Both women and men have mammary glands in humans. They are identical in structure, they differ only in the degree of development. Before puberty, the breasts of girls and boys are no different. With some disorders of the endocrine system, sexually mature men may experience breast enlargement (gynecomastia) and milk secretion occurs. The mammary gland of newborns is also able to produce a secret (the so-called milk of newborns, Lat. lac neonatorum), but this is not a physiological norm.
Further, the breast glands of a woman, which are a female secondary sexual characteristic, are mainly described.
