Lactiferous duct

(Redirected from Mammary duct)

Lactiferous ducts are ducts that converge and form a branched system connecting the nipple to the lobules of the mammary gland. When lactogenesis occurs, under the influence of hormones, the milk is moved to the nipple by the action of smooth muscle contractions along the ductal system to the tip of the nipple. They are also referred to as galactophores, galactophorous ducts, mammary ducts, mamillary ducts or milk ducts.[1][2]

Lactiferous duct
Details
Identifiers
Latinductus lactiferi, tubulus lactiferi
TA98A16.0.02.010
TA27103
FMA58006
Anatomical terminology

Structure

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Lactiferous ducts are lined by a columnar epithelium supported by myoepithelial cells. Prior to 2005, it was thought within the areola the lactiferous duct would dilate to form the lactiferous sinus in which milk accumulates between breastfeeding sessions. However past studies have shown that the lactiferous sinus does not exist.[3]

Function

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The columnar epithelium plays a key role in balancing milk production, milk stasis and reabsorption. The cells of the columnar epithelium form tight junctions which are regulated by hormones and local factors like pressure and casein content. Prolactin and/or placental lactogen are required for tight junction closure while progesterone is the main hormone preventing closure before birth.[4][5]

Clinical significance

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The majority of breast diseases either originate from lactiferous ducts or are closely related. The high susceptibility to benign and malignant diseases is in part a consequence of the cycling hormonal growth stimulation resulting in a high cell turnover and accumulation of defects and complicated hormonal equilibrium which is highly sensitive to disturbance. [citation needed]

See also

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References

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  1. ^ "galactophore". Retrieved 13 August 2017 – via The Free Dictionary.
  2. ^ "galactophorous ducts". Retrieved 13 August 2017.
  3. ^ Ramsay, D. T.; Kent, J. C.; Hartmann, R. A.; Hartmann, P. E. (2005). "Anatomy of the lactating human breast redefined with ultrasound imaging". Journal of Anatomy. 206 (6): 525–534. doi:10.1111/j.1469-7580.2005.00417.x. PMC 1571528. PMID 15960763.
  4. ^ Nguyen, D. A.; Parlow, A. F.; Neville, M. C. (2001). "Hormonal regulation of tight junction closure in the mouse mammary epithelium during the transition from pregnancy to lactation". The Journal of Endocrinology. 170 (2): 347–356. doi:10.1677/joe.0.1700347. PMID 11479131.
  5. ^ Nguyen, D. A.; Neville, M. C. (1998). "Tight junction regulation in the mammary gland". Journal of Mammary Gland Biology and Neoplasia. 3 (3): 233–246. doi:10.1023/A:1018707309361. PMID 10819511. S2CID 36182729.