During breastfeeding, the milk ejection reflex involves oxytocin release from the posterior pituitary. Which specific cellular action does oxytocin produce in the breast?

• A Stimulation of alveolar epithelial cells to synthesize milk proteins
• B Inhibition of prolactin release from anterior pituitary
• C Proliferation of ductal epithelium under estrogen influence
• D Contraction of myoepithelial cells surrounding alveoli to eject milk ✓

Explanation

Oxytocin causes contraction of myoepithelial cells surrounding mammary alveoli, forcing milk into ducts (milk ejection/let-down reflex). Prolactin stimulates milk synthesis, not ejection. Suckling stimulates both oxytocin and prolactin release. This distinction between synthesis (prolactin) and ejection (oxytocin) is frequently tested.

Reference: Ganong's Review of Medical Physiology, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.