The hormone which is responsible for the ejection of milk is?

Appeared in: DSSSB Public Health Nurse - 2015

Explanation

Oxytocin is the hormone responsible for the ejection of milk, a process known as the milk let-down reflex.
It is released from the posterior pituitary gland in response to the infant suckling.
Oxytocin stimulates the contraction of myoepithelial cells surrounding the milk-producing alveoli in the mammary glands.
This contraction forces the milk from the alveoli into the ducts, making it available to the infant.
This process is a neuroendocrine reflex, initiated by nerve signals and completed by hormonal action.

Option A: Prolactin is responsible for the production (synthesis) of milk by the alveolar cells in the breast, not its ejection.
Option C: Estrogen is primarily involved in the growth and development of the breast's ductal system during puberty and pregnancy. High levels of estrogen actually inhibit milk secretion.
Option D: ADH (Antidiuretic Hormone), also known as vasopressin, is released from the posterior pituitary but its main function is to regulate water balance by increasing water reabsorption in the kidneys. It has no direct function in lactation.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal control of lactation as background academic context rather than a clinical decision trigger.
Nurses play a vital role in educating new mothers about the breastfeeding process. Explaining the difference between milk production (prolactin) and milk ejection (oxytocin) can help manage expectations and troubleshoot issues.
A key nursing intervention is to promote a relaxed, comfortable, and private environment for breastfeeding, as stress and anxiety can inhibit the oxytocin reflex and hinder milk let-down.
What if a mother is having trouble with milk let-down? The nurse can suggest techniques to stimulate oxytocin release, such as gentle breast massage, applying warm compresses, thinking about the baby, or looking at a picture of the baby before or during nursing.

How to Approach the Question

First, identify the key action word in the question: "ejection". This is the critical term to define.
Differentiate "ejection" (the release or pushing out of milk) from "production" (the making of milk).
Recall the primary functions of the hormones listed in the options in the context of pregnancy and lactation.
Associate Prolactin with 'P' for Production.
Associate Oxytocin with 'O' for 'Out' (ejection).
Eliminate Estrogen, as its primary role is breast development and it inhibits milk secretion post-delivery.

Concept Tested & Keywords

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E6 Physiology Guyton 4SAE Part 3 p. 69-71

E6 Physiology Essentials Sembulingam 10e Part 2 p. 30-32

E6 Obstetrics Williams p. 48-68

Practise the full DSSSB Public Health Nurse - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.