The posterior pituitary hormone that is crucial for milk ejection isMultiple ChoiceLH.GnRH.oxytocin.prolactin.progesterone.

Identifying the Correct Answer

To answer the question regarding which posterior pituitary hormone is crucial for milk ejection, we need to examine the options provided:

1. LH (Luteinizing Hormone): This is primarily involved in controlling the function of ovaries and testes, and is not directly related to milk ejection.

2. GnRH (Gonadotropin-Releasing Hormone): This hormone stimulates the release of LH and FSH from the anterior pituitary but does not play a role in milk ejection.

3. Oxytocin: This hormone is released from the posterior pituitary and plays a significant role in stimulating milk ejection during breastfeeding. It causes the contraction of myoepithelial cells surrounding the milk ducts, facilitating milk flow.

4. Prolactin: While important for milk production, it is not directly responsible for the ejection of milk.

5. Progesterone: This hormone is involved in preparing the body for pregnancy but does not have a direct role in milk ejection.

Final Answer

The correct answer is oxytocin. This posterior pituitary hormone is crucial for the process of milk ejection during breastfeeding.