Reproductive Physiology Practice Questions

Q: Red cell volume is increased by what percentage in pregnancy?

20 - 30%. ***20 - 30%*** - During pregnancy, **red cell volume** increases by approximately **20-30%** (250-450 mL increase) to meet the increased oxygen demands of the mother and fetus. - However, **plasma volume** increases by a greater proportion (**40-50%**), leading to a dilutional anemia often referred to as **physiologic anemia of pregnancy**. - This disproportionate increase causes a fall in hemoglobin concentration and hematocrit despite the absolute increase in red cell mass. *10 - 20%* - An increase of **10-20%** in red cell volume during pregnancy would be considered **insufficient** for meeting the metabolic demands. - This range is at the lower end of the normal physiological adaptation and could suggest a **suboptimal erythropoietic response**. *30 - 40%* - While a significant increase in red cell volume occurs, **30-40%** is generally higher than the average physiological increase observed. - This percentage more closely reflects the **plasma volume increase** rather than the red cell volume increase. *40 - 50%* - An increase of **40-50%** in red cell volume during pregnancy would be considered **excessive** and outside the normal physiological range. - This percentage actually represents the typical **plasma volume increase**, not the red cell volume increase.

Q: What is the role of growth hormone in the early stages of spermatogenesis?

Stimulates early division of spermatogonia. ***Stimulates early division of spermatogonia*** - **Growth hormone** plays a crucial permissive role in the initial stages of spermatogenesis, primarily by promoting the early **mitotic divisions of spermatogonia**. - This hormone ensures an adequate pool of spermatogonial stem cells to proceed through the later stages of sperm development. *Promotes late division of spermatocytes* - The progression from **primary spermatocytes** to **secondary spermatocytes** involves meiosis I, which is primarily regulated by **FSH** and **testosterone**, not directly by growth hormone. - Growth hormone's main impact is earlier in the proliferation phase of spermatogonia, rather than the meiotic divisions of spermatocytes. *Stimulates Sertoli and Leydig cells* - **Sertoli cells** are primarily stimulated by **FSH**, and **Leydig cells** are stimulated by **LH**, leading to **testosterone production**. - While growth hormone may indirectly influence the overall testicular environment, its direct and primary role is not the stimulation of these specific cell types. *Facilitates formation of acrosomes* - **Acrosome formation** occurs during **spermiogenesis**, the final stage of spermatid maturation. - This process is mainly dependent on **testosterone** and the intricate cellular machinery within the spermatid, with no direct or primary role specifically attributed to growth hormone.

Q: When is the first polar body formed during oogenesis?

First meiotic division. ***First meiotic division*** - The **first polar body** is extruded at the completion of the **first meiotic division** when the primary oocyte divides into a secondary oocyte and the first polar body. - This division is unequal, ensuring the secondary oocyte retains most of the cytoplasm and nutrients essential for future development. *Mitosis* - **Mitosis** is the process where oogonia (germline stem cells) proliferate to form primary oocytes *before* birth. - It results in two identical daughter cells and does not involve the formation of polar bodies. *Second meiotic division* - The **second polar body** is formed upon completion of the **second meiotic division**, which occurs *after fertilization*. - The second meiotic division is triggered when the secondary oocyte is penetrated by a sperm. *Fertilization* - **Fertilization** is the fusion of sperm and egg, which triggers the completion of the **second meiotic division** and the expulsion of the second polar body. - The first polar body has already been formed before fertilization occurs.

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: 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: Which of the following changes is NOT seen during the capacitation of sperm?

Decreased permeability to calcium. ***Decreased permeability to calcium*** - **Capacitation** involves an **influx of calcium ions** into the sperm, which is crucial for subsequent acrosome reaction and hyperactivated motility. - Therefore, a *decrease* in calcium permeability would hinder, not facilitate, the necessary changes for fertilization. *Increased permeability to calcium ions* - This is a **characteristic event** during capacitation, as **calcium influx** triggers downstream signaling pathways. - The increased intracellular calcium is essential for the sperm to undergo the **acrosome reaction** and develop **hyperactivated motility**. *Removal of cholesterol from the sperm membrane* - **Cholesterol efflux** from the sperm plasma membrane is a key event in capacitation, making the membrane more fluid. - This increased fluidity is necessary for the **acrosome reaction** to occur, allowing the outer acrosomal membrane to fuse with the plasma membrane. *Increased motility* - During capacitation, sperm develop **hyperactivated motility**, characterized by a more vigorous and asymmetric flagellar beat. - This change in motility is essential for the sperm to navigate through the female reproductive tract and penetrate the egg's outer layers.

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: Antimullerian hormone is secreted by ?

Both Sertoli cells and granulosa cells. ***Both Sertoli cells and granulosa cells*** - **Antimullerian hormone (AMH)** is produced by **Sertoli cells in males** and **granulosa cells in females** - In **males**: Sertoli cells secrete AMH during fetal development to cause **regression of Müllerian ducts** (which would otherwise develop into uterus, fallopian tubes, and upper vagina) - In **females**: Granulosa cells of developing ovarian follicles secrete AMH, which serves as a **marker of ovarian reserve** and inhibits excessive follicle recruitment - This is the only option that correctly identifies both cell types that produce AMH *Theca cells* - Theca cells are found in ovarian follicles and produce **androgens** (androstenedione and testosterone), not AMH - These androgens are converted to estrogens by granulosa cells via aromatase enzyme - Theca cells do not produce antimullerian hormone *Leydig cells* - Leydig cells are located in the **testes** and produce **testosterone** - They do not produce antimullerian hormone - Only Sertoli cells (not Leydig cells) produce AMH in males *None of the above* - This is incorrect because AMH is indeed produced by specific cell types: **Sertoli cells in males** and **granulosa cells in females**

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

Red cell volume is increased by what percentage in pregnancy?

Accepted Answer

20 - 30%

Answer

10 - 20%

Answer

30 - 40%

Answer

40 - 50%

Question 2

What is the role of growth hormone in the early stages of spermatogenesis?

Accepted Answer

Stimulates early division of spermatogonia

Answer

Promotes late division of spermatocytes

Answer

Stimulates Sertoli and Leydig cells

Answer

Facilitates formation of acrosomes

Question 3

When is the first polar body formed during oogenesis?

Accepted Answer

First meiotic division

Answer

Second meiotic division

Answer

Mitosis

Answer

Fertilization

Question 4

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 5

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 6

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 7

Which of the following changes is NOT seen during the capacitation of sperm?

Accepted Answer

Decreased permeability to calcium

Answer

Removal of cholesterol from the sperm membrane

Answer

Increased permeability to calcium ions

Answer

Increased motility

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

Antimullerian hormone is secreted by ?

Accepted Answer

Both Sertoli cells and granulosa cells

Answer

Theca cells

Answer

Leydig cells

Answer

None of the above

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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