Arrange the following five events in correct order of occurrence?

I. Stimulation of anterior pituitary
II. Stimulation of ovaries
III. Stimulation of neurosecretory cells
IV. Release of gonadotroph hormone
V. Release of gonadotropin releasing hormone

1. A

   III, V, I, IV, II

2. B

   II, IV, I, V, III

3. C

   I, V, III, II, IV

4. D

   IV, V, III, II, I

Appeared in: GMCH Chandigarh - 2019

Explanation

• The correct sequence follows the physiological pathway of the Hypothalamic-Pituitary-Gonadal (HPG) axis.
• The process initiates in the hypothalamus with the stimulation of neurosecretory cells, which then release Gonadotropin-Releasing Hormone (GnRH).
• GnRH acts on the anterior pituitary, causing it to release gonadotropins (LH and FSH).
• Finally, these gonadotropins travel to the ovaries to stimulate follicular development, ovulation, and hormone production.
• This top-down cascade starts from the brain (hypothalamus) and ends at the target organ (ovaries).

Why Other Options Were Wrong

• Option B: This sequence starts with the stimulation of the ovaries (II), which is incorrect. The ovaries are the final target organ in this axis and cannot be stimulated until they receive hormonal signals (LH and FSH) from the pituitary gland.
• Option C: This sequence begins with the stimulation of the anterior pituitary (I). This is incorrect because the anterior pituitary is stimulated by GnRH from the hypothalamus. The process must start in the hypothalamus (III).
• Option D: This sequence starts with the release of gonadotroph hormone (IV) from the pituitary. This is incorrect because the pituitary must first be stimulated by GnRH (V) from the hypothalamus (III) before it can release its own hormones.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal regulation of the female reproductive cycle (HPG Axis) as background academic context rather than a clinical decision trigger.
• Understanding the HPG axis is crucial for diagnosing and treating infertility, menstrual disorders (like amenorrhea or PCOS), and conditions like precocious or delayed puberty.
• Many hormonal contraceptives work by manipulating this axis, typically by providing synthetic estrogen and progestin to suppress the pituitary's release of FSH and LH, thereby preventing ovulation.
• Fertility treatments often involve administering medications that mimic or block hormones at different points in the HPG axis to induce ovulation (e.g., clomiphene citrate) or prepare for IVF.

How to Approach the Question

• First, identify the key anatomical structures and hormones involved: Neurosecretory cells (in the hypothalamus), GnRH, Anterior Pituitary, Gonadotroph hormones (LH/FSH), and Ovaries.
• Recall that hormonal control systems in the brain often follow a top-down hierarchy. The hypothalamus is the master regulator, controlling the pituitary gland.
• Establish the starting point: The process must begin in the hypothalamus with the stimulation of its neurosecretory cells (III). This eliminates options B, C, and D.
• Trace the path: Hypothalamic cells (III) release GnRH (V). GnRH travels to the anterior pituitary and stimulates it (I). The pituitary then releases gonadotropins (IV). Finally, the gonadotropins act on the ovaries (II).
• Assemble the sequence: III → V → I → IV → II.
• Match this sequence with the given options to find the correct answer.

Concept Tested & Keywords

• Concept Tested: Hormonal regulation of the female reproductive cycle (HPG Axis)
• Stem keywords: arrange in order, Stimulation of anterior pituitary, Stimulation of ovaries, Stimulation of neurosecretory cells, Release of gonadotroph hormone, Release of gonadotropin releasing hormone
• Lead-in keywords: Arrange, correct order

Question ID

QSnVQgGVe7jEtdYhoAz4uI

Copy ID

Reference Book

E6 Medicine Harrison 22e Part 2 p. 895-897

E6 Gynecology Williams p. 359-427