Lactiferous duct
| Lactiferous duct | |
|---|---|
 The Breast: cross-section scheme of themammary gland. | |
| Details | |
| Identifiers | |
| Latin | ductus lactiferi,tubulus lactiferi |
| TA98 | A16.0.02.010 |
| TA2 | 7103 |
| FMA | 58006 |
| Anatomical terminology | |
Lactiferous ductsare ducts that converge and form abranched systemconnecting thenippleto thelobulesof themammary gland.When lactogenesis occurs, under the influence of hormones, themilkis 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 asgalactophores,galactophorous ducts,mammary ducts,mamillary ductsormilk ducts.[1][2]
Structure
[edit]Lactiferous ducts are lined by acolumnar epitheliumsupported bymyoepithelial cells.Prior to 2005, it was thought within theareolathe lactiferous duct would dilate to form thelactiferous sinusin which milk accumulates between breastfeeding sessions. However past studies have shown that thelactiferous sinusdoes not exist.[3]
Function
[edit]The columnar epithelium plays a key role in balancing milk production, milk stasis and reabsorption. The cells of the columnar epithelium formtight junctionswhich are regulated by hormones and local factors like pressure andcaseincontent.Prolactinand/orplacental lactogenare required for tight junction closure whileprogesteroneis the main hormone preventing closure before birth.[4][5]
Clinical significance
[edit]The majority ofbreast diseaseseither 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]
- mostbreast cancersarise from the ductal epithelium (seeductal carcinoma in situ)
- phyllodes tumorandintraductal papillomaof the breast
- mastalgiais frequently caused by an imbalance of breast secretion in thelobulesandresorptionin the ducts
- nonpuerperal mastitisis frequently caused by a similar mechanism in combination with aninfection
- duct ectasiais similar and overlapping with the above-mentioned
- subareolar abscessand squamous metaplasia of lactiferous ducts
- most forms offibrocystic breast changesand cysts are thought to originate from lactiferous ducts
See also
[edit]References
[edit]- ^"galactophore".Retrieved13 August2017– via The Free Dictionary.
- ^"galactophorous ducts".Retrieved13 August2017.
- ^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.PMC1571528.PMID15960763.
- ^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.PMID11479131.
- ^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.PMID10819511.S2CID36182729.
