Reproductive Physiology Practice Questions

Q: Gonadotropin levels decline to prepubertal levels by age

6 month to 1 year of age.. ***6 months to 1 year of age*** * Following the **"mini-puberty" of infancy** (where gonadotropin levels surge in the first few months of life), LH and FSH levels progressively decline and typically reach **prepubertal nadir levels by 6-12 months of age**. * This represents the completion of the transitional decline from the neonatal gonadotropin surge to the quiescent prepubertal state. * Most current pediatric endocrinology references cite this timeframe as when gonadotropin levels stabilize at their lowest prepubertal values. *1 year to 2 years of age* * By this age, gonadotropin levels have **already declined** to prepubertal levels and are in a sustained quiescent phase. * This period represents the **maintenance** of low gonadotropin levels rather than the active decline period from infancy. * The initial nadir is typically reached earlier, during the first year of life. *2 years to 3 years of age* * Gonadotropin levels remain at prepubertal nadir during this period, having completed their decline much earlier. * This is part of the prolonged prepubertal quiescence that continues until pubertal activation begins years later. *3 years to 4 years of age* * Similar to 2-3 years, this represents a period of sustained **prepubertal quiescence** with stable low gonadotropin levels. * The decline from neonatal levels occurred years earlier, typically within the first year of life.

Q: Sperm acquires motility in:

Epididymis. ***Correct Answer: Epididymis*** - Sperm mature and acquire **motility** and the ability to fertilize an egg during their transit through the epididymis. - This process is known as **sperm maturation** or **epididymal maturation**, involving changes in sperm ultrastructure, metabolism, and surface molecules. - The epididymis also serves as the primary site for **sperm storage**. *Incorrect: Seminal vesicle* - The seminal vesicles produce a fluid rich in **fructose** (energy for sperm), prostaglandins, and clotting proteins, which contributes to semen volume but does not impart motility. - Seminal vesicles are **glands that secrete fluid**; they do not store sperm. *Incorrect: Ejaculatory duct* - The ejaculatory ducts are formed by the union of the vas deferens and the seminal vesicle ducts; their primary role is to **transport sperm** and seminal fluid into the urethra during ejaculation. - Sperm already possess motility by the time they reach this duct from the epididymis. *Incorrect: Testes* - Sperm are produced in the **seminiferous tubules** of the testes through a process called spermatogenesis. - Newly formed spermatozoa in the testes are **non-motile** and unable to fertilize an ovum.

Q: At the time point indicated by the arrow, the hormone levels are:

Increased estrogen, decreased progesterone. ***Increased estrogen, decreased progesterone*** - The arrow (red circle) points to Day 14, marking the approximate time of **ovulation**. At this point, the graph shows that **estrogen levels peak** just before ovulation and begin to decrease during ovulation. - Progesterone levels are relatively **low** during the follicular phase and only start to significantly increase **after ovulation** as the corpus luteum forms. *Decreased estrogen, increased progesterone* - This hormonal profile is characteristic of the **mid to late luteal phase**, not ovulation. - During the luteal phase, post-ovulation, the **corpus luteum** predominantly produces **progesterone**, leading to its increase, while estrogen levels decline from their pre-ovulatory peak. *Increased estrogen, increased progesterone* - While estrogen is high just before ovulation, **progesterone remains low** until after ovulation. - An increase in both significant progesterone and estrogen would be more indicative of the middle of the **luteal phase** when the corpus luteum is fully functional and producing both hormones in higher amounts. *Decreased estrogen, decreased progesterone* - This hormone profile typically occurs at the **very end of the luteal phase** if pregnancy does not occur, leading to the breakdown of the corpus luteum and subsequent menstruation. - It also characterizes the early follicular phase, not the time around ovulation.

Q: Sertoli cells secrete ?

Inhibin. ***Inhibin*** - **Sertoli cells** secrete **inhibin**, a hormone that selectively inhibits the secretion of **FSH** from the anterior pituitary. - Inhibin plays a crucial role in the **negative feedback loop** regulating spermatogenesis. *Androgen* - **Leydig cells**, not Sertoli cells, are responsible for producing and secreting **androgens**, primarily testosterone. - Androgens are essential for the development of male secondary sexual characteristics and spermatogenesis. *FSH* - **FSH** (Follicle-Stimulating Hormone) is secreted by the **anterior pituitary gland**, not by Sertoli cells. - FSH acts on Sertoli cells to stimulate spermatogenesis. *Testosterone* - **Testosterone** is the primary androgen produced by the **Leydig cells** in the testes. - Sertoli cells respond to testosterone, but they do not secrete it; instead, they convert some of it to estrogen and dihydrotestosterone.

Q: A major function of the epididymis is:

Storage and transport of mature sperm. ***Storage and transport of mature sperm*** - The epididymis is a highly convoluted tubule where **sperm mature** and gain motility over several weeks. - It also serves as a **storage site** for these mature sperm until ejaculation. *Secretion of estrogens* - **Estrogens** are primarily produced by the **ovaries** in females and, to a lesser extent, by the adrenal glands and testes. - The epididymis does not have a significant role in estrogen secretion. *Initiating the development of spermatozoa* - The initiation and primary development of spermatozoa, known as **spermatogenesis**, occurs in the **seminiferous tubules** of the testes. - The epididymis is responsible for further maturation and storage, not initial development. *Production of inhibin* - **Inhibin** is a hormone primarily produced by the **Sertoli cells** in the seminiferous tubules of the testes. - Its main function is to selectively inhibit the secretion of **follicle-stimulating hormone (FSH)** from the anterior pituitary.

Q: Spermatogenesis occurs at which temperature condition?

Temperature lower than core body temperature. ***Temperature lower than core body temperature*** - Spermatogenesis, the process of sperm production, is **temperature-sensitive** and requires a cooler environment than the core body temperature. - The **scrotum** is located outside the abdominal cavity, providing a temperature that is typically 2-3°C lower than the core body temperature, which is optimal for sperm development. *Temperature does not play a role* - This statement is incorrect as temperature plays a crucial role in spermatogenesis; **elevated temperatures can impair sperm production** and function. - Testicular function, including germ cell development, is highly sensitive to heat stress. *Temperature higher than core body temperature* - A temperature higher than core body temperature would be **detrimental to spermatogenesis**, leading to reduced sperm viability and quantity. - Exposure to high temperatures, such as through cryptorchidism (undescended testes), can cause **infertility**. *Body temperature* - If spermatogenesis were to occur at core body temperature, the quality and quantity of sperm would be **significantly reduced**, potentially leading to infertility. - The evolutionary advantage of the testes being located in the scrotum is precisely to maintain this **optimal cooler temperature**.

Q: First sign of pubertal development in a female is ?

Breast enlargement. ***Breast enlargement*** - Breast budding, known as **thelarche**, is typically the **first noticeable sign** of puberty in females, usually occurring between ages 8 and 13. - This development is driven by **estrogen** and marks the beginning of the stages of breast development. *Enlargement of pubic hair* - The appearance of **pubic hair**, known as **pubarche** or **adrenarche**, typically follows thelarche by several months. - While an early sign, it usually appears *after* breast development has begun. *Maximum growth velocity* - The period of **maximum growth velocity** (peak height velocity) usually occurs around **Tanner stage 3 or 4** of puberty. - This growth spurt follows the initial hormonal changes that trigger breast development and the emergence of pubic hair. *Onset of menstruation* - The **onset of menstruation (menarche)** is a *later* event in female pubertal development, typically occurring about **2 to 2.5 years after thelarche**. - It signifies the maturation of the reproductive system and the presence of regular ovulatory cycles.

Q: Which of the following is not secreted by Sertoli cells?

Relaxin. ***Relaxin*** - **Sertoli cells** do not secrete relaxin; it is primarily produced in the **corpus luteum** during pregnancy to relax the pelvic ligaments and cervix. - In males, a small amount of relaxin is produced by the **prostate gland**, contributing to sperm motility. *Inhibin* - **Sertoli cells** secrete inhibin, which negatively regulates **FSH** secretion from the anterior pituitary, providing feedback control for spermatogenesis. - **Inhibin** acts to suppress the synthesis and release of **FSH** in the pituitary gland. *Follistatin* - **Sertoli cells** secrete follistatin, a protein that binds to and inhibits the activity of **activin**, and to a lesser extent, activin-like proteins such as **BMPs**. - Its main role is to regulate the bioavailability and signaling of members of the **TGF-β superfamily**. *Activin* - **Sertoli cells** secrete activin, which generally stimulates **FSH** secretion and *spermatogenesis*, acting in opposition to inhibin. - **Activin** is a dimer composed of two β subunits and has various roles in reproduction, immunology, and inflammation.

Q: Order of development of secondary sexual characteristic in male –

Testicular development–pubic hair–axillary hair–beard. ***Testicular development–pubic hair–axillary hair–beard*** - The first sign of puberty in males is typically an increase in **testicular size**, followed by the appearance of **pubic hair**. - **Axillary hair** usually develops after pubic hair, and the development of a **beard** or facial hair is one of the later secondary sexual characteristics. *Testicular development –beard–pubic hair–axillary hair* - This order incorrectly places **beard growth** and **axillary hair** before **pubic hair**, which is typically the second sign of male puberty. - While testicular development is indeed first, the subsequent sequence of hair development is incorrect. *Axillary hair–beard –pubic hair–testicular development* - This order is incorrect because **testicular development** is the initial event of male puberty, not a later one. - Additionally, both **axillary hair** and **beard growth** typically follow pubic hair development, not precede it. *Pubic hair–testicular development–axillary hair – beard* - This order incorrectly places **pubic hair** development before **testicular development**, which is the primary and earliest sign of puberty in males. - While the sequence of other hair development is later, the initial stage is incorrect.

Q: Sertoli cells play a key role in which of the following processes?

Spermiogenesis. ***Spermiogenesis*** - **Sertoli cells** are crucial for supporting and nourishing developing **spermatids** during their maturation into spermatozoa, a process known as spermiogenesis. - They form the **blood-testis barrier**, which protects germ cells from immune attack and provides a unique microenvironment necessary for this process. *Gonadogenesis* - **Gonadogenesis** is the formation and development of the gonads (testes or ovaries). While Sertoli cells differentiate during male gonadogenesis, they are not the primary drivers of this broader developmental process. - This process involves the differentiation of primordial germ cells and somatic cells, influenced by various genetic and hormonal factors. *Secretion of seminal fluid* - **Seminal fluid** is primarily secreted by accessory glands such as the **seminal vesicles**, **prostate gland**, and **bulbourethral glands**. - Sertoli cells do not directly contribute to the bulk of seminal fluid, although they secrete a fluid component within the seminiferous tubules. *Testosterone secretion* - **Testosterone** is primarily secreted by the **Leydig cells** (also known as interstitial cells of Leydig), which are located in the connective tissue between the seminiferous tubules. - While Sertoli cells produce **androgen-binding protein** that helps maintain high local testosterone concentrations, they do not synthesize testosterone themselves.

Question 1

Gonadotropin levels decline to prepubertal levels by age

Accepted Answer

6 month to 1 year of age.

Answer

3 years to 4 years of age.

Answer

1 year to 2 years of age.

Answer

2 years to 3 years of age.

Question 2

Sperm acquires motility in:

Accepted Answer

Epididymis

Answer

Seminal vesicle

Answer

Ejaculatory duct

Answer

Testes

Question 3

At the time point indicated by the arrow, the hormone levels are:

Accepted Answer

Increased estrogen, decreased progesterone

Answer

Decreased estrogen, increased progesterone

Answer

Increased estrogen, increased progesterone

Answer

Decreased estrogen, decreased progesterone

Question 4

Sertoli cells secrete ?

Accepted Answer

Inhibin

Answer

Androgen

Answer

FSH

Answer

Testosterone

Question 5

A major function of the epididymis is:

Accepted Answer

Storage and transport of mature sperm

Answer

Secretion of estrogens

Answer

Initiating the development of spermatozoa

Answer

Production of inhibin

Question 6

Spermatogenesis occurs at which temperature condition?

Accepted Answer

Temperature lower than core body temperature

Answer

Temperature does not play a role

Answer

Temperature higher than core body temperature

Answer

Body temperature

Question 7

First sign of pubertal development in a female is ?

Accepted Answer

Breast enlargement

Answer

Appearance of pubic hair

Answer

Maximum growth velocity

Answer

Onset of menstruation

Question 8

Which of the following is not secreted by Sertoli cells?

Accepted Answer

Relaxin

Answer

Inhibin

Answer

Follistatin

Answer

Activin

Question 9

Order of development of secondary sexual characteristic in male –

Accepted Answer

Testicular development–pubic hair–axillary hair–beard

Answer

Testicular development –beard–pubic hair–axillary hair

Answer

Axillary hair–beard –pubic hair–testicular development

Answer

Pubic hair–testicular development–axillary hair – beard

Question 10

Sertoli cells play a key role in which of the following processes?

Accepted Answer

Spermiogenesis

Answer

Gonadogenesis

Answer

Secretion of seminal fluid

Answer

Testosterone secretion

Reproductive Physiology — MCQs

Reproductive Physiology — MCQs

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