Anatomy and Physiology of Lactation Flashcards

A mother reports that her milk supply seems lower on stressful days. This is most likely because stress hormones such as adrenaline (epinephrine) interfere with:

Answer: Oxytocin release and the milk ejection reflex

Epinephrine causes vasoconstriction and antagonizes oxytocin action at the myoepithelial cells, inhibiting let-down even when milk is present in the alveoli.

Hind milk differs from fore milk primarily in that it has:

Answer: Higher fat content

Fat content increases progressively as the breast is drained during a feeding; hind milk (milk released later in a feed) has significantly more fat than fore milk drawn at the start.

Which sensory nerve pathway is primarily responsible for transmitting the suckling stimulus to the hypothalamus to trigger prolactin and oxytocin release?

Answer: Intercostal nerves T4–T6

Sensory afferents carried by intercostal nerves T4–T6 innervate the nipple-areolar complex and relay suckling signals to the hypothalamus, triggering neurohormonal responses.

Inverted nipples may interfere with latch because they involve:

Answer: Fibrotic bands tethering the nipple inward

Inverted nipples are caused by shortened or fibrotic connective tissue bands that retract the nipple inward, preventing adequate protrusion for the infant to latch effectively.

Breast fullness (engorgement) that persists without adequate milk removal can lead to a decrease in supply due to:

Answer: Accumulation of FIL and pressure-induced inhibition of secretion

When milk is not removed, FIL accumulates and intramammary pressure rises, both of which locally downregulate milk synthesis to prevent alveolar damage.

In a mother with insufficient glandular tissue (IGT), the primary underlying issue affecting milk production is:

Answer: Inadequate number of milk-producing alveolar cells

IGT involves hypoplastic breast tissue with fewer alveoli and lobules, directly limiting the total milk-producing capacity regardless of hormonal status or feeding frequency.

The 'draught' or 'let-down' reflex can be conditioned over time so that it is triggered by:

Answer: Sensory cues such as hearing the baby cry or thinking about nursing

Oxytocin release can be classically conditioned to auditory, visual, or emotional cues associated with nursing, which is why mothers often experience spontaneous let-down when they hear their baby cry.