Milk ejection hormone is

RRB Nsg. Superintendent-20 July 2019 (Shift-2)

Applied Physiology

Easy

Appeared in: RRB Nsg. Superintendent-20 July 2019 (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 the infant suckling or crying.
Oxytocin acts on the myoepithelial cells that surround the alveoli in the mammary glands.
The contraction of these cells forces milk from the alveoli into the ducts, making it available to the infant.

Option B: Vasopressin, also known as Antidiuretic Hormone (ADH), is primarily involved in regulating water retention in the kidneys and blood pressure. It does not play a role in milk ejection.
Option C: Progesterone is essential for the development of the breast's lobule-alveolar system during pregnancy, but it actively inhibits the secretion of milk before delivery.
Option D: Prolactin is the hormone responsible for milk production (lactogenesis), stimulating the synthesis of milk within the alveolar cells of the breast. It does not cause 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.
The milk ejection reflex is a neuroendocrine reflex, meaning it involves both the nervous system and hormones. Psychological factors like stress, pain, or anxiety can inhibit oxytocin release and prevent milk let-down, a common issue for new mothers. Nurses play a key role in providing a calm, supportive environment to facilitate breastfeeding.
Synthetic oxytocin (e.g., Syntocinon nasal spray) can be prescribed to help mothers who have difficulty with the milk let-down reflex, demonstrating the direct clinical application of this physiological knowledge.
What if a mother's milk lets down when she hears her baby cry? This is a normal conditioned response. The neural pathways for oxytocin release can be triggered by auditory (crying) or visual (seeing the baby) cues, not just the physical act of suckling.

How to Approach the Question

This is a factual recall question testing knowledge of endocrine physiology.
Identify the key physiological process in the question stem: 'milk ejection'.
It is critical to differentiate 'milk ejection' (the let-down reflex) from 'milk production' (lactogenesis), as they are controlled by different hormones.
Recall the primary functions of the hormones listed in the options.
Match the function to the hormone: Oxytocin is responsible for ejection/let-down, while Prolactin is responsible for production.
Eliminate the other options based on their primary roles: Vasopressin (water balance) and Progesterone (breast development and inhibition of lactation during pregnancy).

Concept Tested & Keywords

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