Final answer:
A galactagogue is an agent that promotes milk flow. Prolactin and oxytocin play key roles in milk production and ejection during breastfeeding.
Step-by-step explanation:
The term that best means an agent that encourages the flow of milk is galactagogue. When a baby suckles at the breast, it stimulates the nerve impulses which in turn signal the hypothalamus to instruct the pituitary gland to release prolactin. Prolactin is crucial for the production of milk in the mammary glands. Furthermore, the hormone oxytocin is released during suckling and it causes the myoepithelial cells to contract, pushing milk from the alveoli into the lactiferous ducts, facilitating the flow of milk. This is part of a positive feedback loop; the more the baby suckles, the more milk is produced, which in turn encourages the baby to continue to suckle.