What is the role of human chorionic gonadotropin (hCG) if pregnancy occurs?
To stimulate the development of new follicles
To trigger menstruation
To rescue the corpus luteum and maintain its hormone production
To inhibit the production of progesterone
The Correct Answer is C
hCG is a glycoprotein hormone secreted by the trophoblast cells of the developing embryo shortly after implantation, typically detectable in maternal serum by day 8–10 post-ovulation. Its primary role is to rescue the corpus luteum, preventing its degeneration and allowing continued secretion of progesterone and estrogen. These hormones maintain the decidualized endometrium, preventing menstruation and supporting early pregnancy. hCG shares structural similarity with LH and binds to LH receptors on the corpus luteum. Peak serum hCG levels reach 100,000–200,000 mIU/mL by 10 weeks gestation.
Rationale for correct answer
C. hCG prevents luteolysis by acting on LH receptors of the corpus luteum, maintaining its progesterone production. This sustains the endometrial lining for implantation and early embryonic development.
Rationale for incorrect answers
A. hCG does not stimulate new follicle development. In fact, high progesterone and estrogen levels maintained by the corpus luteum inhibit FSH, preventing new folliculogenesis during early pregnancy.
B. hCG prevents menstruation by maintaining the corpus luteum and its hormone output. Menstruation is triggered by progesterone withdrawal, which hCG directly prevents.
D. hCG supports the continued production of progesterone, not its inhibition. It ensures the endometrial lining remains intact until the placenta takes over hormone production around week 10–12.
Take home points
- hCG maintains the corpus luteum during early pregnancy.
- It prevents menstruation by supporting progesterone production.
- hCG mimics LH and binds to LH receptors on luteal cells.
- It does not promote follicle development or suppress progesterone.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Corpus luteum
The corpus luteum is a temporary endocrine structure formed from the ruptured Graafian follicle after ovulation. It secretes high levels of progesterone, moderate estrogen, and minimal inhibin A to maintain the luteal phase of the menstrual cycle. Progesterone levels peak around day 21 of a 28-day cycle and range from 5–20 ng/mL in the mid-luteal phase. Its main role is to stabilize the endometrial lining for potential implantation and to inhibit GnRH, FSH, and LH via negative feedback. If fertilization does not occur, it regresses into the corpus albicans, causing a drop in hormones and onset of menstruation.
Rationale for correct answer
B. The corpus luteum secretes progesterone during the luteal phase to maintain the endometrium for possible implantation. It forms after ovulation and is hormonally dependent on LH for function.
Rationale for incorrect answers
A. Estrogen is secreted mainly by the dominant follicle during the follicular phase, not by the corpus luteum. The follicular phase precedes ovulation, and the corpus luteum forms after ovulation.
C. The ovum is released by the ruptured follicle due to the LH surge, not by the corpus luteum. The corpus luteum forms after ovulation and plays no direct role in ovum release.
D. GnRH is secreted by the hypothalamus and regulated by sex steroid feedback. The corpus luteum does not stimulate GnRH; in fact, progesterone from the corpus luteum inhibits it.
Take home points
- The corpus luteum secretes progesterone to maintain the endometrium.
- It forms after ovulation from the ruptured follicle.
- It does not release the ovum; that happens before it forms.
- Its hormones inhibit GnRH, FSH, and LH to prevent further ovulation.
Correct Answer is B
Explanation
The corpus luteum is formed from the ruptured ovarian follicle after ovulation and functions as a temporary endocrine gland, primarily secreting progesterone (5–20 ng/mL mid-luteal) and smaller amounts of estrogen. It maintains the endometrium in preparation for implantation. If fertilization and implantation do not occur, the absence of human chorionic gonadotropin (hCG) causes the corpus luteum to degenerate around day 24–26 of a typical 28-day cycle. It then becomes a fibrous scar tissue called the corpus albicans, leading to a drop in progesterone and estrogen levels, and triggering menstruation.
Rationale for correct answer
B. If fertilization does not occur, the corpus luteum degenerates due to lack of hCG support and transforms into the corpus albicans. This structural regression leads to hormonal withdrawal and menstruation.
Rationale for incorrect answers
A. Progesterone secretion continues only if fertilization occurs and hCG is produced by the trophoblast. Without hCG, the corpus luteum involutes and stops secreting hormones.
C. The corpus luteum forms after ovulation; it does not trigger it. Ovulation is triggered by the LH surge prior to corpus luteum formation.
D. The corpus luteum secretes some estrogen, but its primary function is progesterone production. After degeneration, it no longer produces either hormone in significant amounts.
Take home points
- The corpus luteum regresses into the corpus albicans without fertilization.
- Hormonal support from hCG is necessary to sustain the corpus luteum.
- Progesterone levels drop, triggering menstruation.
- The corpus luteum does not cause ovulation; it follows it.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.