Milk ejection hormone is?

ESIC Nursing Officer 2016 (Shift -2)

Obstetrics & Gynaecology

Easy

Appeared in: ESIC Nursing Officer 2016 (Shift -2)

Explanation

Oxytocin is the primary hormone responsible for the milk ejection reflex, also known as the let-down reflex.
It is released from the posterior pituitary gland in response to stimuli like infant suckling or crying.
Oxytocin acts on the myoepithelial cells surrounding the alveoli of the mammary glands, causing them to contract.
This contraction forces the milk that has been produced into the milk ducts, making it available to the infant.

Option B: Vasopressin, also known as Antidiuretic Hormone (ADH), is primarily involved in regulating water retention by the kidneys and increasing blood pressure. It does not play a role in milk ejection.
Option C: Prolactin is essential for lactation, but its function is to stimulate the synthesis and production of milk within the alveolar cells of the breast. It does not cause the milk to be ejected.
Option D: Progesterone, along with estrogen, has an inhibitory effect on milk secretion during pregnancy. A significant drop in progesterone levels after delivery is necessary for lactation to begin.

Visual 1: Diagram: The Milk Ejection Reflex. A flowchart showing the neurohormonal pathway: Infant suckling -> Nerve signals to hypothalamus -> Oxytocin release from posterior pituitary -> Contraction of myoepithelial cells -> Milk ejection.

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.
Understanding the difference between prolactin (for production) and oxytocin (for ejection) is crucial for nurses to troubleshoot breastfeeding issues. A mother might produce sufficient milk but experience difficulty with let-down due to factors like stress or pain, which can inhibit oxytocin release.
Nursing interventions such as promoting a calm and comfortable environment, encouraging skin-to-skin contact, and providing adequate pain relief can facilitate the oxytocin reflex and enhance breastfeeding success.
What if? If a mother experiences postpartum pituitary necrosis (Sheehan syndrome), she would likely be unable to lactate. This is because the damaged pituitary cannot produce prolactin for milk synthesis or release oxytocin for milk ejection.

How to Approach the Question

First, identify the key term in the question: 'milk ejection'.
Recall the two main hormones involved in breastfeeding: Prolactin and Oxytocin.
Differentiate their specific roles. Prolactin is for 'PROduction' of milk.
Oxytocin is for the 'ejection' or 'let-down' of milk, which is an active process of contraction.
Associate Oxytocin with its contractile function on smooth muscle (myoepithelial cells in the breast, uterus during labor).
Eliminate the other options based on their primary functions: Vasopressin (water balance) and Progesterone (inhibits lactation during pregnancy).

Concept Tested & Keywords

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