Hormone responsible for milk ejection is?

Appeared in: AIIMS Rishikesh & Jodhpur NO - 2017

Explanation

Oxytocin, a hormone released from the posterior pituitary gland, is responsible for the ejection of milk from the mammary glands.
It functions by stimulating the contraction of myoepithelial cells that surround the milk-producing alveoli in the breast.
This process is known as the milk let-down reflex, which is a neuroendocrine reflex initiated by the infant's suckling.
Psychological factors like hearing a baby cry can also trigger oxytocin release, while stress or pain can inhibit it.

Option B: Prolactin is responsible for the synthesis or production of milk (lactogenesis) within the breast alveoli, not its ejection.
Option C: Antidiuretic Hormone (ADH), also known as vasopressin, is primarily involved in regulating water balance by controlling water reabsorption in the kidneys.
Option D: Insulin is a pancreatic hormone that regulates the metabolism of carbohydrates, fats, and protein by promoting the absorption of glucose from the blood into liver, fat, and skeletal muscle cells.

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 milk production (prolactin) and milk ejection (oxytocin) is crucial for nurses when troubleshooting breastfeeding difficulties.
Maternal stress, pain, or anxiety can inhibit oxytocin release, leading to a poor let-down reflex even when milk supply is adequate. Nurses can teach relaxation techniques to help facilitate this reflex.
Synthetic oxytocin (e.g., Syntocinon nasal spray) is sometimes prescribed to assist mothers who have difficulty with milk ejection.

How to Approach the Question

This is a factual recall question testing knowledge of endocrine physiology related to lactation.
Identify the key phrase in the question: "milk ejection".
Differentiate between the two primary hormones involved in breastfeeding: Prolactin and Oxytocin.
Use a mnemonic: Prolactin is for milk Production.
Recall that Oxytocin is responsible for the other major step: milk ejection or "let-down". Think of the 'O' in Oxytocin as for getting the milk 'Out'.
Evaluate the other options. ADH (water balance) and Insulin (blood sugar) have primary functions unrelated to lactation, making them incorrect.

Concept Tested & Keywords

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

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

E6 Obstetrics Williams p. 48-68

Practise the full AIIMS Rishikesh & Jodhpur NO - 2017

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