Which is the major galactokinetic hormone?

Appeared in: KPSC Staff Nurse - 2021

Explanation

Oxytocin is the major galactokinetic hormone, which means it is responsible for the ejection or 'let-down' of milk from the mammary glands.
It is released from the posterior pituitary gland in response to stimuli like infant suckling or even hearing a baby cry.
Oxytocin acts on the myoepithelial cells that surround the milk-producing alveoli in the breast, causing them to contract and expel milk into the ducts.

Option A: Prolactin is a galactopoietic hormone, not galactokinetic. Its primary role is to stimulate the synthesis and production of milk within the breast alveoli.
Option B: Estrogen, along with progesterone, prepares the breasts for lactation during pregnancy but actually inhibits the secretion of milk. Its levels must fall after delivery for lactation to begin.
Option D: Progesterone works with estrogen to develop the breast's lobule-alveolar system during pregnancy, but it also inhibits milk secretion.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal regulation of lactation, specifically the milk ejection reflex as background academic context rather than a clinical decision trigger.
Nurses play a key role in educating new mothers on how to promote the let-down reflex, suggesting techniques like skin-to-skin contact, a calm and private environment, gentle breast massage, and relaxation exercises.
It is important to counsel mothers that stress, pain, and anxiety can inhibit oxytocin release, thereby hindering milk ejection. Effective pain management postpartum is crucial for successful breastfeeding.
What if? If a mother experiences significant difficulty with the let-down reflex despite a good latch and supportive measures, a synthetic oxytocin nasal spray may be prescribed to help trigger milk ejection before feeding.

How to Approach the Question

This is a factual recall question based on physiological terminology.
First, identify and define the key term in the question: 'galactokinetic'.
Break down the word: 'galacto-' refers to milk, and '-kinetic' refers to movement or ejection.
Differentiate this from the similar term 'galactopoietic', where '-poietic' means 'to make' or 'produce'.
Recall the specific hormones responsible for each function: Oxytocin for milk ejection (kinetic) and Prolactin for milk production (poietic).
Select the option that matches the 'kinetic' or ejection function.

Concept Tested & Keywords

Concept Tested: Hormonal regulation of lactation, specifically the milk ejection reflex.
Stem keywords: galactokinetic hormone, major
Lead-in keywords: Which is

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

E6 Obstetrics Williams p. 48-68

E6 Physiology Essentials Sembulingam 10e Part 2 p. 150-152

Practise the full KPSC Staff Nurse - 2021

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