Product Code Database
The mammary ridge or mammary crest is a primordium specific for the development of mammary gland.
In human embryogenesis, the mammary ridge usually appears as a narrow, microscopic thickening during the first seven weeks of pregnancy and grows caudally as a narrow, linear ridge. In many mammals, these glands first appear as elevated ridges along the milk lines, which then separate into individual buds located in regions lateral to the ventral midline. The location of these buds varies according to species: they are located in the thorax region in primates, in the Groin area in , and along the entire length of the trunk in and .
A mammary ridge, or crest, usually stops growing at eight weeks and its length is regressed starting at the caudal end and extending Cranium, so that what remains is a round, placode where the axilla develops. When shortening of the mammary crest is complete, the structure remains prominent in the areas where the mammary glands eventually form. The mammary lines begin to shorten and ectodermal cells begin to divide and grow into the mesenchymal cell layer. A basement membrane separating the expanding ectodermal crest structure and the underlying mesoderm usually remains. The mammary ridge then becomes recognizable in the Thorax region in the human embryo. Nipples develop on the milk lines of mammals.
A recently published study demonstrates that focal fat pads on the front of human torsos are of mammary ridge origin. Eight pairs of fatty mounds were consistently found running along a curved line from the armpits to the groins in nearly all lean women and men, consistent with the location of the embryological mammary ridge line. This finding explains why fat on the front of the body is less responsive to diet and exercise than fat elsewhere in most people—because it is actually of breast origin and therefore sensitive more to hormonal influence than caloric intake or burn.
|
|
