Reproductive Physiology Practice Questions

Q: Which of the following is a primary hormonal action of progesterone during the menstrual cycle?

Promotes secretory changes in the endometrium. ***Promotes secretory changes in the endometrium*** - **Progesterone**, produced by the **corpus luteum** after ovulation, acts on the **endometrium**, causing the uterine glands to become coiled and fill with secretions. - This prepares the **endometrium** for potential **implantation** of a fertilized egg, thickening the uterine lining and making it receptive. *Increases uterine sensitivity to oxytocin* - **Estrogen** is primarily responsible for increasing **myometrial** sensitivity to **oxytocin**, especially during late pregnancy and labor. - **Progesterone** actually tends to *decrease* uterine contractility and sensitivity to **oxytocin** to maintain pregnancy. *Inhibits secretion of luteinizing hormone (LH)* - While both **estrogen** and **progesterone** can exert **negative feedback** on the **hypothalamus** and **pituitary**, particularly at high levels, the primary role of progesterone during the **luteal phase** is to maintain the uterine lining. - The peak of **LH** secretion occurs *before* ovulation, driven by a surge in estrogens, while progesterone levels rise *after* ovulation. *Reduces body temperature* - **Progesterone** is known to have a **thermogenic effect**, causing a slight increase in **basal body temperature (BBT)** after ovulation. - This rise in **BBT** is often used as an indicator of ovulation in fertility tracking.

Q: After how many days post-ovulation does the corpus luteum begin to regress?

10 days. ***10 days*** - The corpus luteum begins to regress approximately **9-11 days post-ovulation** in the absence of pregnancy, making **10 days** the correct answer. - This regression, known as **luteolysis**, is triggered by declining levels of **LH** and leads to decreased production of **progesterone** and **estrogen**. - The functional regression marks the end of the luteal phase and precedes menstruation by approximately 3-4 days. *5 days* - At 5 days post-ovulation, the corpus luteum is in its **active growth phase** and approaching peak function. - **Progesterone** levels are rising to maintain the endometrium, not declining. - Regression has not yet begun at this early stage of the luteal phase. *24 days* - This timing is too late - at 24 days post-ovulation (approximately day 38 of the cycle), menstruation would have already occurred. - In a typical **28-day cycle**, menstruation begins around day 14 post-ovulation. - Such delayed regression would only occur with **pregnancy** and hCG support, preventing luteolysis. *None of the options* - This is incorrect because **10 days** is the medically accurate answer, falling within the established 9-11 day timeframe for corpus luteum regression.

Q: What hormone is primarily responsible for the onset of pubarche?

Dehydroepiandrosterone (DHEA). ***Dehydroepiandrosterone (DHEA)*** - **DHEA** and its sulfate (DHEA-S) are **adrenal androgens** primarily responsible for the development of **pubarche**, which includes the growth of **pubic and axillary hair**. - This process is known as **adrenarche**, which often precedes gonadarche (the maturation of the gonads). *Luteinizing Hormone (LH)* - **LH** is crucial for **gonadarche**, stimulating **testosterone production** in males and ovulation in females. - While it contributes to overall pubertal development, it is not the primary hormone for the initial appearance of pubic hair. *Follicle-Stimulating Hormone (FSH)* - **FSH** also plays a key role in **gonadarche**, promoting **spermatogenesis** in males and follicle development in females. - Its primary action is on the gonads, not directly on the development of pubarche. *Testosterone* - **Testosterone** is an important androgen responsible for **secondary sexual characteristics** in males, such as muscle mass increase, deepening of the voice, and some aspects of pubic hair development. - However, the initial onset of pubarche is driven more by **adrenal androgens** like DHEA, rather than gonadal testosterone.

Q: Within what timeframe after ovulation does fertilization typically occur?

12-24 hours. ***12-24 hours*** - The **ovum** is viable for fertilization for a relatively short period, typically **12 to 24 hours** after its release during ovulation. - For fertilization to occur, **sperm** must be present in the fallopian tube within this critical window. *5-6 days* - This timeframe is more characteristic of the **duration that sperm can survive** in the female reproductive tract, rather than the viability of the ovum for fertilization. - If sperm are present in the reproductive tract up to **5-6 days before ovulation**, they may still fertilize the egg once it's released. *8-12 days* - This period extends significantly beyond the **viability of the ovum** for fertilization. - An ovum released during ovulation will have degenerated and will no longer be capable of being fertilized after 24 hours. *> 12 days* - Fertilization cannot occur this late after ovulation as the **egg would have long since degenerated**. - This timeframe is not relevant to the process of fertilization itself.

Q: Which of the following hormones play an important role in pubertal development?

All of the options play a role in puberty.. ***All of the options play a role in puberty.*** - Puberty is a complex process involving the interplay of various hormones, including **gonadotropins (LH)**, **sex steroids (testosterone)**, and metabolic hormones like **leptin**. - All these hormones contribute directly or indirectly to the **initiation and progression of pubertal development**. *Luteinizing Hormone (LH)* - While essential for **gonadal steroid production** and a key marker of puberty, LH alone does not *initiate* the process; it is part of a larger hormonal cascade. - LH levels rise significantly *during* puberty to stimulate the gonads, but its release is ultimately triggered by **GnRH**. *Testosterone* - **Testosterone** is crucial for the development of **secondary sexual characteristics** in males and contributes to growth in both sexes during puberty. - However, its production is stimulated by LH, meaning it acts downstream in the pubertal cascade and is not the sole initiator. *Leptin* - **Leptin**, a hormone produced by **adipose tissue**, is thought to play a permissive role in the timing of puberty. - High enough **body fat stores** and therefore adequate leptin levels are believed to signal to the brain that the body has sufficient energy reserves for reproductive development, but it's not the direct hormonal trigger.

Q: Day 20 of menstrual cycle falls under which phase?

Luteal phase. ***Luteal phase*** - The **luteal phase** typically starts after ovulation, around day 14, and lasts until menstruation begins, usually day 28 of a 28-day cycle. Therefore, **day 20 falls squarely within this phase**. - During this phase, the **corpus luteum** forms and produces **progesterone**, preparing the uterus for potential pregnancy. *Menstrual phase* - The **menstrual phase** is the period of shedding of the uterine lining, typically occurring from **day 1 to day 5** of the menstrual cycle. - Day 20 is well past this phase, during which bleeding and low hormone levels are characteristic. *Follicular phase* - The **follicular phase** starts on day 1 of menstruation and lasts until ovulation, usually around **day 13-14** in a 28-day cycle. - During this phase, follicles mature under the influence of **FSH** and **estrogen** levels rise. Day 20 is beyond this period. *Ovulation phase* - The **ovulation phase** is a short period, typically around **day 14** of a 28-day cycle, when the mature egg is released from the ovary. - This phase is brief and marks the transition from the follicular to the luteal phase, so day 20 is considerably after ovulation.

Q: Which of the following is an estrogen-dependent pubertal change?

Vaginal Cornification. ***Vaginal Cornification*** - Vaginal cornification refers to the **maturation and stratification of the vaginal epithelium** under the direct influence of **estrogen**. - Estrogen stimulates the **proliferation of vaginal epithelial cells**, leading to thickening of the vaginal mucosa and increased glycogen content in the superficial cells. - This is a **purely estrogen-dependent change** and is one of the key markers of estrogenic activity during puberty. - The vaginal maturation index increases with estrogen exposure, making this a reliable indicator of estrogenic stimulation. *Menstruation* - While estrogen is important for endometrial proliferation, menstruation requires the **coordinated action of both estrogen AND progesterone**. - Estrogen builds the endometrium during the proliferative phase, but **progesterone** is essential for the secretory transformation. - Menstruation occurs due to the **withdrawal of both hormones**, not estrogen alone, making it dependent on both hormones rather than purely estrogen-dependent. *Cervical mucus* - Cervical mucus characteristics are influenced by **both estrogen and progesterone** throughout the menstrual cycle. - Estrogen makes mucus thin, watery, and stretchy (spinnbarkeit), while progesterone makes it thick and viscous. - This **dual hormonal regulation** means it is not purely estrogen-dependent. *Hair growth* - Pubertal hair growth, including **pubic and axillary hair**, is primarily stimulated by **androgens** (testosterone, DHEA-S from the adrenal glands). - This process is called **adrenarche** and is androgen-dependent, not estrogen-dependent.

Q: Which hormone is predominantly secreted after 14 days of the menstrual cycle?

Progesterone. ***Correct: Progesterone*** - After **ovulation**, which typically occurs around day 14 of a 28-day cycle, the ruptured follicle transforms into the **corpus luteum**. - The **corpus luteum** primarily secretes **progesterone**, which is crucial for preparing the **endometrium** for potential implantation. - Progesterone is the **predominant hormone** of the **luteal phase** (days 14-28). *Incorrect: Estrogen* - **Estrogen** levels rise significantly during the **follicular phase** (days 1-14), peaking just before ovulation. - After ovulation, **estrogen** levels decrease slightly and then rise again during the **luteal phase**, but its predominant role is earlier in the cycle. *Incorrect: LH (Luteinizing Hormone)* - **LH** experiences a surge around day 14, known as the **LH surge**, which triggers **ovulation**. - After this surge, LH levels decline and remain relatively low throughout the rest of the **menstrual cycle**, though it's essential for maintaining the **corpus luteum**. *Incorrect: FSH (Follicle-Stimulating Hormone)* - **FSH** is highest during the early **follicular phase**, stimulating the growth and development of ovarian follicles. - Its levels decrease as **estrogen** rises and remain low after ovulation, as its primary role is follicle maturation, not luteal phase events.

Q: Oxygen consumption increases in pregnancy by

20%. ***20%*** - During **pregnancy**, the maternal **metabolic rate increases** to support fetal growth and the physiological changes occurring in the mother's body. - This increased metabolic demand leads to a **rise in oxygen consumption** by approximately 20% compared to the non-pregnant state. *10%* - A 10% increase is an **underestimation** of the physiological change in oxygen consumption during pregnancy. - The demands of supporting a growing fetus and increased maternal tissue mass require a more substantial metabolic adjustment. *30%* - While oxygen consumption does increase significantly, a 30% rise is generally considered an **overestimation** of the average increase. - The typical physiological adaptation usually falls within the 15-25% range. *40%* - A 40% increase in oxygen consumption would represent an **extreme physiological demand** that is not typically observed during an uncomplicated pregnancy. - Such a drastic increase might indicate underlying pathology rather than normal adaptation.

Q: Testes are not palpable in

SRY deletion. ***SRY deletion*** - **SRY (Sex-determining Region Y) gene** is the master regulator of male sex determination on the Y chromosome; its deletion in 46,XY individuals results in **Swyer syndrome** (pure gonadal dysgenesis). - Without functional SRY, **testes fail to develop entirely**, and the gonads remain as non-functional **streak gonads** rather than differentiating into either testes or ovaries. - Result: **No palpable testes** because testicular tissue never forms; individuals develop female external genitalia despite XY karyotype. *DAX1 deletion* - DAX1 (NR0B1) normally **antagonizes testicular development** and supports adrenal/gonadal development. - **Deletion of DAX1** would actually **reduce anti-testis effects**, allowing testicular development to proceed more readily if SRY is present. - DAX1 **duplications** (not deletions) can impair male development; deletions cause **adrenal hypoplasia congenita** but do not prevent testicular formation. *WNT-4 gene mutation* - **WNT4** promotes **ovarian development** and opposes male differentiation pathways in normal female development. - **Loss-of-function mutations** in WNT4 do not prevent testicular development in 46,XY individuals where SRY is present and functional. - WNT4 overexpression (not loss-of-function mutation) could theoretically interfere with male development, but standard WNT4 mutations do not cause absent testes. *RSPO-1 gene mutation* - **RSPO1** (R-spondin 1) enhances **Wnt/β-catenin signaling** and supports ovarian differentiation; primarily relevant in 46,XX sex development. - Loss-of-function mutations in RSPO1 lead to **46,XX testicular/ovotesticular DSD**, where testicular tissue develops inappropriately in XX individuals. - In 46,XY individuals with functional SRY, RSPO1 mutations would **not prevent testicular development**, so testes would be palpable.

Question 1

Which of the following is a primary hormonal action of progesterone during the menstrual cycle?

Accepted Answer

Promotes secretory changes in the endometrium

Answer

Increases uterine sensitivity to oxytocin

Answer

Inhibits secretion of luteinizing hormone (LH)

Answer

Reduces body temperature

Question 2

After how many days post-ovulation does the corpus luteum begin to regress?

Accepted Answer

10 days

Answer

None of the options

Answer

5 days

Answer

24 days

Question 3

What hormone is primarily responsible for the onset of pubarche?

Accepted Answer

Dehydroepiandrosterone (DHEA)

Answer

Testosterone

Answer

Luteinizing Hormone (LH)

Answer

Follicle-Stimulating Hormone (FSH)

Question 4

Within what timeframe after ovulation does fertilization typically occur?

Accepted Answer

12-24 hours

Answer

5-6 days

Answer

8-12 days

Answer

> 12 days

Question 5

Which of the following hormones play an important role in pubertal development?

Accepted Answer

All of the options play a role in puberty.

Answer

Luteinizing Hormone (LH)

Answer

Testosterone

Answer

Leptin

Question 6

Day 20 of menstrual cycle falls under which phase?

Accepted Answer

Luteal phase

Answer

Menstrual phase

Answer

Follicular phase

Answer

Ovulation phase

Question 7

Which of the following is an estrogen-dependent pubertal change?

Accepted Answer

Vaginal Cornification

Answer

Cervical mucus

Answer

Menstruation

Answer

Hair growth

Question 8

Which hormone is predominantly secreted after 14 days of the menstrual cycle?

Accepted Answer

Progesterone

Answer

Estrogen

Answer

LH

Answer

FSH

Question 9

Oxygen consumption increases in pregnancy by

Accepted Answer

20%

Answer

10%

Answer

30%

Answer

40%

Question 10

Testes are not palpable in

Accepted Answer

SRY deletion

Answer

DAX 1 deletion

Answer

WNT- 4 gene mutation

Answer

RSPO-1 gene mutation

Reproductive Physiology — MCQs

Reproductive Physiology — MCQs

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