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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 ...
During both of these periods, progesterone levels are high. Because the hormonal profile of a pregnant female and a female in diestrus are the same, sometimes a non-pregnant female will go through a period of pseudopregnancy. At that time she may gain weight, have mammary gland development, produce milk, and exhibit nesting behaviours. 4.
Despite the apparent necessity of GH/IGF-1 signaling in pubertal breast development however, women with Laron syndrome, in whom the growth hormone receptor (GHR) is defective and insensitive to GH and serum IGF-1 levels are very low, puberty, including breast development, is delayed, although full sexual maturity is always eventually reached. [15]
The mammary ridge is primordial for the mammary glands on the chest in humans, and is associated with mammary gland and breast development.. In human embryogenesis, the mammary ridge usually appears as a narrow, microscopic ectodermal thickening during the first seven weeks of pregnancy and grows caudally as a narrow, linear ridge. [1]
Branching morphogenesis is also evident in the ductal formation of the mammary gland. [23] [17] Primitive duct formation begins in development, but the branching formation of the duct system begins later in response to estrogen during puberty and is further refined in line with mammary gland development. [17] [24] [25]
As a mammary gland, the breast is composed of differing layers of tissue, predominantly two types: adipose tissue; and glandular tissue, which affects the lactation functions of the breasts. [17]: 115 The natural resonant frequency of the human breast is about 2 hertz. [18] Morphologically, the breast is tear-shaped. [19]
The mammary glands of mammals are specialized to produce milk, a liquid used by newborns as their primary source of nutrition. The monotremes branched early from other mammals and do not have the teats seen in most mammals, but they do have mammary glands. The young lick the milk from a mammary patch on the mother's belly.
The increased secretion of testosterone from the testes during puberty causes the male secondary sexual characteristics to be manifested. [23] Testosterone directly increases size and mass of muscles, vocal cords, and bones, deepening of the voice, and changing the shape of the face and skeleton. [1]