Lactation Specialist Anatomy & Physiology of Lactation Flashcards

What are the primary milk-producing secretory cells in the breast alveoli called?

Answer: Lactocytes (alveolar epithelial cells)

Lactocytes, also called alveolar epithelial cells, are the specialized secretory cells lining the alveoli that synthesize and secrete milk components.

Which hormone is primarily responsible for driving milk synthesis (galactopoiesis) during established lactation?

Answer: Prolactin

Prolactin, secreted by the anterior pituitary gland in response to suckling, is the primary hormone driving ongoing milk synthesis.

What is the primary physiologic role of oxytocin in breastfeeding?

Answer: Triggering the milk ejection (let-down) reflex

Oxytocin, released from the posterior pituitary, causes myoepithelial cells surrounding alveoli to contract, propelling milk through the ducts in what is called the milk ejection reflex.

During pregnancy, full milk production is suppressed primarily by elevated levels of which hormone?

Answer: Progesterone

High progesterone levels during pregnancy block prolactin receptor activity on lactocytes, inhibiting copious milk secretion despite rising prolactin.

Which structures transport milk from the alveoli toward the nipple openings?

Answer: Lactiferous ducts

Lactiferous ducts form a branching network that collects milk from the alveolar lobules and channels it to the nipple pores for delivery to the infant.

Which of the following can inhibit the milk ejection (let-down) reflex?

Answer: Stress and elevated catecholamine levels

Stress hormones such as epinephrine cause vasoconstriction and can antagonize oxytocin action at the myoepithelial cells, inhibiting let-down.

Which phase of lactogenesis refers specifically to the onset of copious milk secretion after delivery?

Answer: Lactogenesis II

Lactogenesis II occurs approximately 30-40 hours postpartum when progesterone withdrawal allows prolactin to stimulate large-volume milk production — commonly described as milk 'coming in.'