The hormone is secreted by the posterior pituitary?

Appeared in: JODHPUR AIIMS SNO-2018

Explanation

The posterior pituitary gland (neurohypophysis) stores and releases two hormones that are synthesized in the hypothalamus: Oxytocin and Antidiuretic Hormone (ADH).
Oxytocin's primary functions are to stimulate uterine smooth muscle contractions during childbirth and to cause milk ejection (let-down) from the mammary glands in response to suckling.
Among the given options, only Oxytocin is secreted by the posterior pituitary.

Option A: Luteinizing hormone (LH) is a gonadotropin secreted by the anterior pituitary gland, not the posterior pituitary.
Option C: Melanocyte-stimulating hormone (MSH) is produced by the pars intermedia of the anterior pituitary gland.
Option D: Prolactin (PRL) is secreted by the anterior pituitary gland and is responsible for milk production (lactogenesis).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormones of the Pituitary Gland as background academic context rather than a clinical decision trigger.
A synthetic form of oxytocin, known as Pitocin, is one of the most common drugs used in obstetrics to induce or augment labor and to control postpartum hemorrhage.
Understanding the difference between Prolactin and Oxytocin is crucial for lactation counseling. Prolactin makes the milk, while Oxytocin moves the milk.
What if? If a patient has difficulty with milk ejection but is producing milk, the issue may lie with oxytocin release (posterior pituitary) rather than prolactin levels (anterior pituitary). This could be due to stress or pain, which can inhibit oxytocin secretion.

How to Approach the Question

First, identify the key term in the question stem: 'posterior pituitary'.
Recall the basic anatomy and physiology of the endocrine system, specifically the pituitary gland.
Remember that the pituitary has two lobes: anterior and posterior, each secreting different hormones.
Systematically recall the hormones of the posterior pituitary: Antidiuretic Hormone (ADH) and Oxytocin.
Scan the given options to see if either ADH or Oxytocin is listed.
The option 'Oxytocin' matches the recalled knowledge. The other options (Luteinizing, Melanocyte secreting, Prolactin) are all associated with the anterior pituitary.

Concept Tested & Keywords

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E6 Nursing Brunner Adult Health 3SA Vol 1 Part 4 p. 9-11

E6 Physiology Ganong 27e Vol 1 Part 2 p. 92-94

E6 Physiology Essentials Sembulingam 10e Part 2 p. 28-30

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