Hormone responsible for ovulation is?

ESIC Nursing Officer 2016 (Shift -2)

Obstetrics & Gynaecology

Easy

Appeared in: ESIC Nursing Officer 2016 (Shift -2)

Explanation

Luteinizing Hormone (LH) is the primary hormone that directly triggers the event of ovulation.
This occurs via a massive, rapid release from the anterior pituitary gland, known as the 'LH surge,' which typically happens 16-32 hours before ovulation.
The LH surge causes the final maturation of the oocyte and stimulates enzymatic activity that weakens the wall of the mature Graafian follicle, leading to its rupture and the release of the ovum.

Option A: FSH's main role is to stimulate the growth and maturation of ovarian follicles during the follicular phase. It does not directly trigger their rupture.
Option C: Estrogen is produced by the growing follicle, and its peak level provides positive feedback to the pituitary, which in turn causes the LH surge. It is an indirect cause, not the direct trigger of ovulation.
Option D: While both hormones are essential for the menstrual cycle, only LH has the specific, direct role of triggering the event of ovulation. Their functions are distinct.

Visual 1: Diagram - A graph showing the hormonal fluctuations (FSH, LH, Estrogen, Progesterone) throughout the 28-day menstrual cycle. The diagram should clearly label the follicular phase, ovulation, and luteal phase, with a prominent peak for the LH surge just before ovulation.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal regulation of ovulation as background academic context rather than a clinical decision trigger.
Ovulation predictor kits (OPKs) sold over-the-counter work by detecting the LH surge in urine, helping individuals identify their most fertile window for conception.
Infertility treatments often manipulate these hormones. For example, human chorionic gonadotropin (hCG), which mimics LH activity, is frequently administered to trigger final follicle maturation and ovulation in assisted reproductive technologies like IVF.
What if? If a patient has anovulatory cycles (cycles without ovulation) due to an absent LH surge, a key nursing role is patient education about potential treatments, such as exogenous gonadotropin administration, and the importance of timed intercourse or procedures based on induced ovulation.

How to Approach the Question

First, identify the key physiological event in the question: 'ovulation'.
Next, recall the sequence of hormonal events that regulate the menstrual cycle.
Differentiate between the hormones that prepare for the event (FSH for follicle growth, Estrogen for endometrial growth and feedback) and the hormone that acts as the direct trigger.
Remember the mnemonic 'LH Surge -> Ovulation'. The surge in Luteinizing Hormone is the specific, direct trigger for the rupture of the follicle.
Based on this, eliminate the other options. FSH prepares the follicles, and Estrogen sets the stage for the LH surge, but LH is the final actor that causes ovulation.

Concept Tested & Keywords

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