Final answer:
The let-down reflex is essential for breastfeeding and is activated when an infant suckles, leading to milk ejection facilitated by oxytocin release. However, it can be inhibited by physical or emotional stress, high progesterone levels, and other discomforts felt by the mother.
Step-by-step explanation:
The let-down reflex, also known as the milk ejection reflex, is a key component in breastfeeding, creating a positive feedback loop that ensures continuous milk production as long as the infant suckles. Sensory nerve fibers in the areola are stimulated when the infant suckles, prompting the posterior pituitary to release oxytocin. This, in turn, causes myoepithelial cells to contract and expel milk from the alveoli into the lactiferous ducts, which then drains into the lactiferous sinuses, and is finally expelled through the nipple pores.
However, the release of oxytocin and the subsequent let-down reflex can be affected by various factors. High levels of emotional or physical stress can significantly inhibit oxytocin release, complicating the let-down reflex. Moreover, hormones play a role; for instance, estrogen stimulates while progesterone inhibits oxytocin production, which may impact the reflex. Factors like pain, discomfort, anxiety, and lack of confidence can also interfere with this delicate process, inhibiting the successful execution of the let-down reflex.