Reproductive Physiology Practice Questions

Q: Human placental lactogen (HPL) has activity similar to which hormone?

Growth hormone. **Growth hormone** - **Human placental lactogen (HPL)**, also known as **human chorionic somatomammotropin (hCS)**, is a polypeptide hormone produced by the placental syncytiotrophoblast. - HPL shares approximately **96% structural homology** with **growth hormone (GH)** and has both **somatotropic** (growth-promoting) and **lactogenic** activities. - HPL acts on maternal metabolism by promoting **lipolysis**, **insulin resistance**, and maintaining **glucose availability** for the fetus—actions similar to growth hormone's metabolic effects. - This makes growth hormone the correct answer for hormones with similar activity to HPL. *Oxytocin* - **Oxytocin** is a posterior pituitary hormone primarily involved in **uterine contractions** during labor and **milk ejection reflex** during lactation. - It is structurally a nonapeptide and functionally unrelated to HPL's metabolic and growth-promoting effects. - HPL has no structural or functional similarity to oxytocin. *Insulin* - **Insulin** is a pancreatic hormone that promotes **glucose uptake** by cells and **lowers blood glucose** levels. - While HPL causes maternal **insulin resistance** (anti-insulin effect) to spare glucose for the fetus, HPL itself does not have insulin-like activity. - HPL and insulin are structurally and functionally distinct hormones with opposing metabolic effects. *All of the options* - HPL has specific activity similar to **growth hormone** due to structural homology and shared metabolic actions. - HPL does **not** have activity similar to oxytocin or insulin. - Therefore, this option is incorrect as HPL's activity does not mimic all listed hormones.

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: 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 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: 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: 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: 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.

Question 1

Human placental lactogen (HPL) has activity similar to which hormone?

Accepted Answer

Growth hormone

Answer

Oxytocin

Answer

Insulin

Answer

All of the options

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

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 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

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 8

Red cell volume is increased by what percentage in pregnancy?

Accepted Answer

20 - 30%

Answer

10 - 20%

Answer

30 - 40%

Answer

40 - 50%

Question 9

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 10

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

Reproductive Physiology — MCQs

Reproductive Physiology — MCQs

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