Reproductive Physiology Practice Questions

Q: Which of the following is not correlated with the ovarian cycle?

Estrous cycle. ***Estrous cycle*** - The **estrous cycle** is characteristic of most mammals (e.g., cows, dogs, cats) and differs fundamentally from the human **menstrual cycle**. - Unlike the menstrual cycle which involves endometrial shedding, the estrous cycle typically involves the reabsorption of the **endometrium** with no bleeding. *Endometrial sampling* - **Endometrial sampling** (e.g., biopsy) is directly impacted by the ovarian cycle, as the **endometrium** undergoes proliferative and secretory phases under hormonal influence. - The appearance and cellular characteristics of the **endometrium** vary significantly depending on the cycle phase (e.g., changes in glandular architecture, stromal edema). *Vaginal cytology* - **Vaginal cytology** reflects the hormonal changes of the ovarian cycle, particularly the influence of **estrogen** and **progesterone**. - The types and proportions of **squamous cells** in a vaginal smear (e.g., basal, parabasal, intermediate, superficial cells) vary with the follicular and luteal phases. *Blood hormonal levels* - **Blood hormonal levels** (e.g., **estradiol**, **progesterone**, **LH**, **FSH**) are direct indicators and regulators of the ovarian cycle. - Fluctuations in these hormones drive the development of the **follicle**, **ovulation**, and the formation and regression of the **corpus luteum**.

Q: What hormone is primarily responsible for triggering the LH surge?

Estrogen. ***Estrogen*** - As the dominant follicle matures, it produces increasing amounts of **estrogen**, primarily **estradiol**. - When **estradiol** levels reach a critical threshold, it switches from negative to positive feedback on the hypothalamus and anterior pituitary, leading to the **LH surge**. *Anti-Mullerian Hormone (AMH)* - **AMH** is produced by granulosa cells of small antral follicles and is a marker of **ovarian reserve**. - It plays a role in regulating follicular development but is not directly responsible for initiating the **LH surge**. *Follicle-Stimulating Hormone (FSH)* - **FSH** stimulates the growth and development of ovarian follicles, which in turn produce estrogen. - While essential for follicular development, the surge is not triggered by FSH itself but rather by the high **estrogen** levels resulting from FSH action. *Progesterone* - **Progesterone** levels rise significantly **after** the LH surge and ovulation, primarily from the corpus luteum, to prepare the uterus for implantation. - It acts to inhibit further LH and FSH release and is not the primary trigger for the initial **LH surge**.

Q: After ejaculation, semen liquefies in:

30 minutes. ***30 minutes*** - Normal semen typically **liquefies** within **15 to 30 minutes** after ejaculation due to the action of enzymes, primarily prostatic-specific antigen (PSA), which break down the seminal coagulum. - This liquefaction is crucial for sperm motility and subsequent fertilization as it allows the sperm to become motile and advance into the female reproductive tract. *10 minutes* - While initial liquefaction may begin earlier, complete liquefaction within **10 minutes** is generally considered too rapid and could indicate an underlying issue, such as **prostatitis**. - Rapid liquefaction might signify a deficient formation of the seminal coagulum, which is essential to protect sperm immediately after ejaculation. *75 minutes* - If semen takes **longer than 60 minutes** to liquefy, it is termed **delayed liquefaction**, which can impair sperm motility and viability. - Delayed liquefaction can be a cause of male infertility and may point to issues such as seminal vesicle or prostatic dysfunction. *120 minutes* - Liquefaction after **120 minutes** is severely delayed and abnormal, significantly hindering **sperm movement** and thus reducing the chances of conception. - Such prolonged liquefaction times often warrant further diagnostic investigation into the functionality of the male accessory glands.

Q: What is the shortest phase of the sexual cycle?

Orgasm phase. ***Orgasm phase*** - The **orgasm phase** is characterized by a rapid, intense physiological release, typically lasting only a few seconds. - It is the peak of sexual arousal and involves involuntary muscle contractions and a surge of pleasure. *Excitement phase* - The **excitement phase** is the initial stage of sexual arousal, which can last from minutes to several hours. - It involves physiological changes like increased heart rate, blood flow to genitals, and muscle tension. *Plateau phase* - The **plateau phase** follows the excitement phase and can last for several minutes. - During this phase, sexual tension intensifies, leading to further physiological changes such as increased heart rate, breathing, and blood pressure, often leading directly into orgasm. *Resolution phase* - The **resolution phase** is the post-orgasmic period where the body returns to its unaroused state. - This phase typically lasts longer than the orgasm phase, as blood flow and muscle tension gradually subside.

Q: In which phase of the sexual response cycle does the erection of the penis occur?

Arousal phase. ***Arousal phase*** - The **arousal phase** (or excitement phase) is the initial stage of the sexual response cycle, characterized by **vasocongestion** leading to penile erection in males. - During this phase, physiological changes such as increased heart rate, blood pressure, and muscle tension begin to occur, preparing the body for sexual activity. *Plateau phase* - The **plateau phase** follows arousal and is marked by intensified physiological responses, but the primary **erection** usually occurs during the arousal phase. - This phase involves further increases in muscle tension, heart rate, and deeper breathing, maintaining but typically not initiating penile erection. *Orgasm phase* - The **orgasm phase** is the peak of sexual arousal, involving rhythmic muscle contractions and the release of sexual tension. - While erection is crucial for achieving orgasm, the erection itself occurs well before this stage, as part of the initial arousal. *Resolution phase* - The **resolution phase** is the return of the body to its pre-aroused state, during which physiological responses subside and **erection is lost**. - This phase occurs after orgasm and is characterized by a refractory period in males.

Q: Amenorrhoea following hyperprolactinemia is caused by ?

Inhibition of GnRH pulse secretion. ***Inhibition of GnRH pulse secretion*** - Elevated **prolactin** levels (hyperprolactinemia) directly **suppress the pulsatile release of GnRH** from the hypothalamus. - This suppression leads to decreased FSH/LH secretion, disrupting the menstrual cycle and causing amenorrhea. *Inhibition of adrenal steroidogenesis* - Hyperprolactinemia does not primarily inhibit **adrenal steroidogenesis**; its main reproductive effects are at the hypothalamic-pituitary-gonadal axis. - Adrenal insufficiency would present with a different clinical picture, not typically isolated amenorrhea due to hyperprolactinemia. *It causes hypogonadotropic hypogonadism* - While hyperprolactinemia *leads to* **hypogonadotropic hypogonadism**, this option describes a consequence rather than the direct mechanism of amenorrhea. - The mechanism is *how* the hypogonadotropic hypogonadism is caused, which is through GnRH inhibition. *It leads to formation of ovarian cysts* - Hyperprolactinemia generally does not lead to the formation of **ovarian cysts**; it primarily suppresses ovarian function rather than stimulating cyst formation. - Polycystic ovary syndrome (PCOS) is associated with ovarian cysts but has different hormonal imbalances, including elevated androgens and insulin resistance.

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: In spermatogenesis, independent assortment of paternal and maternal chromosomes occurs during-

Primary to secondary spermatocyte. ***Primary to secondary spermatocyte*** - This transition involves **meiosis I**, specifically **anaphase I**, where homologous chromosomes separate and independently assort. - **Independent assortment** is the random orientation of homologous chromosome pairs at the metaphase plate in meiosis I, leading to genetic diversity. *Spermatogonia to primary spermatocyte* - This stage involves **mitotic division** and cellular growth, not meiosis. - Genetic recombination and independent assortment are characteristic of meiosis, not mitosis. *Secondary spermatocyte to spermatids* - This stage involves **meiosis II**, where sister chromatids separate. - While chromosomes align and separate, the primary event for independent assortment of homologous chromosomes occurs in meiosis I. *Spermatids to spermatozoa* - This process is called **spermiogenesis**, which is a maturation process involving morphological changes but not cell division. - No further genetic recombination or chromosome segregation occurs during this transformation.

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: 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.

Question 1

Which of the following is not correlated with the ovarian cycle?

Accepted Answer

Estrous cycle

Answer

Vaginal cytology

Answer

Blood hormonal levels

Answer

Endometrial sampling

Question 2

What hormone is primarily responsible for triggering the LH surge?

Accepted Answer

Estrogen

Answer

Anti-Mullerian Hormone (AMH)

Answer

Follicle-Stimulating Hormone (FSH)

Answer

Progesterone

Question 3

After ejaculation, semen liquefies in:

Accepted Answer

30 minutes

Answer

10 minutes

Answer

75 minutes

Answer

120 minutes

Question 4

What is the shortest phase of the sexual cycle?

Accepted Answer

Orgasm phase

Answer

Excitement phase

Answer

Plateau phase

Answer

Resolution phase

Question 5

In which phase of the sexual response cycle does the erection of the penis occur?

Accepted Answer

Arousal phase

Answer

Plateau phase

Answer

Orgasm phase

Answer

Resolution phase

Question 6

Amenorrhoea following hyperprolactinemia is caused by ?

Accepted Answer

Inhibition of GnRH pulse secretion

Answer

It leads to formation of ovarian cysts

Answer

Inhibition of adrenal steroidogenesis

Answer

It causes hypogonadotropic hypogonadism

Question 7

Red cell volume is increased by what percentage in pregnancy?

Accepted Answer

20 - 30%

Answer

10 - 20%

Answer

30 - 40%

Answer

40 - 50%

Question 8

In spermatogenesis, independent assortment of paternal and maternal chromosomes occurs during-

Accepted Answer

Primary to secondary spermatocyte

Answer

Spermatogonia to primary spermatocyte

Answer

Secondary spermatocyte to spermatids

Answer

Spermatids to spermatozoa

Question 9

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 10

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)

Reproductive Physiology — MCQs

Reproductive Physiology — MCQs

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