Q. A 28-year-old primigravida at 41 weeks gestation comes to the birthing center for induction of labor. She is anxious about the birthing process. As her FNP, you explain the role of various hormones in labor and delivery to help ease her anxiety. You mention oxytocin, a hormone that plays a crucial role in uterine contractions and milk ejection. Which of the following is the primary site of production of oxytocin?