Lactiferous duct of breast contraction is due to:

Ans. C. Oxytocin* Oxytocin primarily results in stimulation of two specific types of muscular contraction:* Uterine muscular contraction during parturition* Breast lactiferous duct myoepithelial contraction during milk let down reflex.A Brief on Breast Functional Anatomy* The areola is central, pigmented portion of breast with a diameter of about 2.5cm.* Accessory glands located around the periphery of the areola are Montgomery glands (they can secrete milk).* The nipple accommodates about 15-20 lactiferous ducts and their openings.* Each milk duct (lactiferous duct) dilates to form lactiferous sinus at about 5-10mm away from its opening in the nipple. Lactiferous sinus acts as reservoir of milk.* The lining epithelium of the duct near the opening is stratified squamous. Each alveolus is lined by columnar epithelium where milk secretion occurs.* Myoepithelial cells are the network of branching longitudinal striated cells which surround the alveoli and the smaller ducts. There is a dense network of capillaries surrounding the alveoli. These are situated between the basement membrane and epithelial lining.* Contraction of these cells (in response to oxytocin) squeezes the alveoli and ejects the milk into the larger duct