Milk ejection is due to?

BSF Staff Nurse - 2015

Applied Physiology

Easy

Appeared in: BSF Staff Nurse - 2015

Explanation

Oxytocin, which is responsible for the milk ejection or 'let-down' reflex.
Suckling stimulates nerve endings in the nipple, sending signals to the hypothalamus.
The hypothalamus then directs the posterior pituitary gland to release oxytocin into the bloodstream.
Oxytocin causes the myoepithelial cells, which are tiny muscles surrounding the milk-producing alveoli in the breast, to contract.
This contraction forces the milk from the alveoli into the ducts, making it available for the baby to drink.

Option A: Estrogen is primarily involved in the growth and development of the breast's ductal system during pregnancy. High levels of estrogen actually inhibit the secretion of milk before delivery.
Option B: Prolactin is the hormone responsible for milk synthesis or production. It stimulates the alveolar cells of the breast to make milk, but it does not cause the milk to be ejected.
Option D: Follicle-Stimulating Hormone (FSH) is a gonadotropic hormone that regulates the functions of the ovaries in females. It stimulates the growth of ovarian follicles and has no direct role 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, specifically the milk ejection reflex as background academic context rather than a clinical decision trigger.
Understanding the let-down reflex is vital for nurses supporting breastfeeding mothers. The reflex can be conditioned to other stimuli, like the baby's cry, but it can also be inhibited by stress, pain, or anxiety.
Nursing interventions to promote milk let-down include creating a calm and private environment, ensuring the mother is comfortable and pain-free, encouraging skin-to-skin contact, and applying warm compresses to the breast before feeding.
What if? If a mother is experiencing significant postpartum pain or emotional stress, her let-down reflex may be inhibited, leading to difficulty breastfeeding and infant frustration. The nurse's priority is to manage the mother's pain and provide emotional support and relaxation techniques to facilitate the reflex.

How to Approach the Question

First, identify the key physiological process in the question stem: 'milk ejection'.
Recall the two primary hormones involved in lactation: Prolactin and Oxytocin.
Differentiate their specific roles. A useful mnemonic is: Prolactin is for Production, while Oxytocin is for getting the milk Out.
Evaluate the options based on this differentiation. 'Milk ejection' directly corresponds to the function of Oxytocin.
Eliminate the other options by recalling their primary functions: Estrogen (breast development, milk inhibition) and FSH (ovarian cycle), which are not directly responsible for milk ejection.

Concept Tested & Keywords

Concept Tested: Hormonal control of lactation, specifically the milk ejection reflex.
Stem keywords: Milk ejection
Lead-in keywords: is due to

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