Hormone responsible for ovulation and development of corpus luteum is?

KPSC Staff Nurse - 2016

Obstetrics & Gynaecology

Easy

Appeared in: KPSC Staff Nurse - 2016

Explanation

Luteinizing Hormone (LH) is directly responsible for triggering the final maturation and rupture of the dominant ovarian follicle, an event known as ovulation.
This process is initiated by a dramatic mid-cycle 'LH surge,' where LH levels increase 6- to 10-fold.
Following ovulation, LH stimulates the transformation of the remaining follicular cells into the corpus luteum, a process called luteinization.
LH continues to support the corpus luteum, which then produces progesterone to prepare the uterus for a potential pregnancy.

Option A: Follicle-Stimulating Hormone (FSH) is primarily responsible for stimulating the growth and recruitment of ovarian follicles at the beginning of the menstrual cycle (follicular phase), not for triggering ovulation itself.
Option C: Antidiuretic Hormone (ADH), or vasopressin, is involved in regulating the body's water balance by controlling water reabsorption in the kidneys. It has no direct role in the reproductive or menstrual cycle.
Option D: While estrogen is crucial for the menstrual cycle, its main roles are to build up the uterine lining (endometrium) and, at peak levels, to provide positive feedback to the pituitary to cause the LH surge. It does not directly cause ovulation or form the corpus luteum.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal regulation of the menstrual cycle, specifically ovulation and the luteal phase as background academic context rather than a clinical decision trigger.
Ovulation predictor kits (OPKs) used for fertility planning work by detecting the LH surge in urine, which signals that ovulation is likely to occur within 24-36 hours.
In Polycystic Ovary Syndrome (PCOS), a common endocrine disorder, LH levels are often persistently elevated, which disrupts the normal LH surge mechanism, leading to anovulation and infertility.
What if? If the LH surge fails to occur or is insufficient, the follicle will not rupture. This results in an anovulatory cycle, where no egg is released, making conception impossible for that cycle. The unruptured follicle may become a follicular cyst.

How to Approach the Question

This is a factual recall question testing knowledge of reproductive physiology.
First, break down the question into its core components: the hormone responsible for (1) ovulation and (2) development of the corpus luteum.
Next, systematically review the function of each hormone listed in the options.
Recall that FSH stimulates follicle growth.
Recall that the 'LH surge' is the direct trigger for ovulation, and 'luteinizing' refers to its role in forming the corpus luteum.
Recall that ADH is related to kidney function and water balance, making it irrelevant.

Concept Tested & Keywords

Concept Tested: Hormonal regulation of the menstrual cycle, specifically ovulation and the luteal phase.
Stem keywords: hormone, ovulation, development of corpus luteum
Lead-in keywords: responsible for
Negative lead-in flag: false

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E6 Medicine Harrison 22e Part 2 p. 1032-1034

E6 Physiology Guyton 4SAE Part 3 p. 35-37