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Lactation - Anatomy & Physiology (view source)
Revision as of 17:41, 7 December 2010
, 17:41, 7 December 2010no edit summary
* '''Milk ejection''': the expulsion of milk from alveoli
* '''Milk ejection''': the expulsion of milk from alveoli
* '''Involution''': termination of milk secretion and mammary gland regression.
* '''Involution''': termination of milk secretion and mammary gland regression.
==Involution==
* As the requirement for milk by the neonate decreases, suckling is less frequent.
* Consequently, there is a buildup of pressure in the mammary gland causing secretory cells to become increasingly less functional - '''pressure atrophy'''.
* Secretory cells then remain non-functional until a subsequent pregnancy, at which time prolactin, glucocorticoids and placental lactogen restimulate alveolar milk synthesis.
* During involution, immune cells such as lymphocytes and macrophages invade the mammary tissue. These produce immunoglobulins in the subsequent lactation.
* Involution is critical to allow the replacement of senescent secretory cells which are lost by apoptosis.
* In rodents, '''defoliation''' occurs. Secretory epithelial cells are sloughed from the basement membrane at involution. Thus, more extensive regeneration is required at the onset of the subsequent lactation.
[[Category:Lactation]]
[[Category:Lactation]]