Regarding the physiology of lactation, which statement is CORRECT?

• A Prolactin stimulates milk synthesis, and oxytocin causes milk ejection ✓
• B Oxytocin stimulates milk production in the alveoli
• C Estrogen and progesterone inhibit lactation during pregnancy by blocking prolactin receptors
• D Prolactin is responsible for milk ejection from the breast

Explanation

Prolactin stimulates milk synthesis in alveolar cells, while oxytocin causes contraction of myoepithelial cells for milk ejection (let-down reflex). During pregnancy, high estrogen and progesterone inhibit lactation by suppressing prolactin action on the breast, not by blocking prolactin receptors. After delivery, the fall in estrogen and progesterone permits prolactin to act.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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