Microscopic Anatomy of Reproductive System — MCQs
What is the primary reason for infertility in Sertoli cell only syndrome?
One of the risks of the endometrial biopsy that was performed on this patient is perforation of the uterus. The endometrial biopsy device is placed through the cervix and into the endometrial cavity. If complete perforation occurs, what is the sequence of layers that the biopsy device would penetrate prior to entering the peritoneal cavity?
A major function of the epididymis is:
Sertoli cells secrete:
Investigation of choice for Posterior urethral valves?
Blood testis barrier in testis is formed by?
Remnants of Wolffian ducts in a female are found in
Development of labia majora is from -
The nasopharynx is primarily lined by which type of epithelium?
Which artery supplies the ductus deferens?
Microscopic Anatomy of Reproductive System Indian Medical PG Practice Questions and MCQs
Question 1: What is the primary reason for infertility in Sertoli cell only syndrome?
- A. Too many Sertoli cells inhibit spermatogenesis via inhibin
- B. Proper blood-testis barrier is not established
- C. Sufficient numbers of spermatozoa are not produced
- D. The absence of germ cells in this condition. (Correct Answer)
Explanation: ***The absence of germ cells in this condition.*** - **Sertoli cell only syndrome** is characterized by the complete or near-complete absence of germ cells in the seminiferous tubules [2]. - Since germ cells are the precursors to spermatozoa, their absence directly results in the inability to produce sperm, leading to **infertility** [1]. *Too many Sertoli cells inhibit spermatogenesis via inhibin* - While Sertoli cells produce **inhibin B**, which negatively regulates FSH, the primary issue in Sertoli cell only syndrome is the lack of germ cells, not an overabundance of Sertoli cells or excessive inhibin production causing inhibition [1]. - The syndrome is defined by the *absence of germ cells*, not by a functional alteration of Sertoli cells due to their quantity. *Proper blood-testis barrier is not established* - The **blood-testis barrier (BTB)** is formed by tight junctions between Sertoli cells and is crucial for creating an immunological barrier for developing germ cells [2]. - While disruptions in BTB integrity can impair spermatogenesis, the primary cause of infertility in Sertoli cell only syndrome is the *absence of the cells that the barrier is meant to protect* (germ cells), rather than a failure of the barrier itself. *Sufficient numbers of spermatozoa are not produced* - This statement is true as a *result* of infertility, but it does not explain the *primary reason* for it. - The lack of spermatozoa is a direct consequence of the **absence of germ cells**, which are necessary precursors for sperm production [1].
Question 2: One of the risks of the endometrial biopsy that was performed on this patient is perforation of the uterus. The endometrial biopsy device is placed through the cervix and into the endometrial cavity. If complete perforation occurs, what is the sequence of layers that the biopsy device would penetrate prior to entering the peritoneal cavity?
- A. Ovary, fallopian tube, broad ligament
- B. Endometrium, myometrium, serosa (Correct Answer)
- C. Round ligament, cardinal ligament, uterosacral ligament
- D. Serosa, myometrium, endometrium
Explanation: ***Endometrium, myometrium, serosa*** - The **endometrium** is the innermost lining layer of the uterus and is the first layer encountered by the biopsy device within the uterine cavity [1]. - The **myometrium** is the thick muscular middle layer of the uterine wall, which lies superficial to the endometrium and deep to the serosa [1]. - The **peritoneum** (also known as the serosa or perimetrium when referring to the uterus) is the outermost layer of the uterus that covers the myometrium, and once perforated, the device enters the peritoneal cavity [4]. *Ovary, fallopian tube, broad ligament* - The **ovaries** and **fallopian tubes** are located lateral to the uterus, and the **broad ligament** is a fold of peritoneum that supports the uterus, ovaries, and fallopian tubes [3]. - These structures are not directly superior or immediately adjacent to the uterine wall in such a way that they would be sequentially penetrated during a direct anterior-posterior perforation from the uterine cavity. *Round ligament, cardinal ligament, uterosacral ligament* - The **round, cardinal, and uterosacral ligaments** are supportive structures of the uterus located externally to the uterine wall. - They would not be encountered in a direct transmural penetration from within the uterine cavity into the peritoneal cavity. *Serosa, myometrium, endometrium* - This sequence describes penetration in the reverse direction, from the **peritoneal cavity** inward towards the uterine lumen. - An endometrial biopsy device starts within the **endometrial cavity**, so it would penetrate from inside out [2].
Question 3: A major function of the epididymis is:
- A. Storage and transport of mature sperm (Correct Answer)
- B. Secretion of estrogens
- C. Initiating the development of spermatozoa
- D. Production of inhibin
Explanation: ***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.
Question 4: Sertoli cells secrete:
- A. Androstenedione
- B. Testosterone
- C. Inhibin (Correct Answer)
- D. Estrogen
Explanation: ***Inhibin*** - **Sertoli cells** secrete **inhibin**, a hormone that selectively inhibits the secretion of **follicle-stimulating hormone (FSH)** from the anterior pituitary. - This negative feedback mechanism helps regulate **spermatogenesis**. *Androstenedione* - **Androstenedione** is primarily produced by the **adrenal glands** and **gonads** (Leydig cells in males, theca cells in females). - It serves as a precursor in the biosynthesis of **testosterone** and **estrogen**. *Testosterone* - **Testosterone** is predominantly secreted by the **Leydig cells** in the testes, stimulated by luteinizing hormone (LH). - While Sertoli cells are crucial for spermatogenesis, they do not directly produce significant amounts of testosterone. *Estrogen* - In males, **estrogen** is produced in small amounts primarily through the aromatization of androgens (like testosterone) in various tissues, including **Leydig cells** and adipose tissue. - While Sertoli cells have estrogen receptors, they are not a primary source of estrogen production.
Question 5: Investigation of choice for Posterior urethral valves?
- A. Ultrasound
- B. Retrograde urethrography
- C. Micturating Cystourethrography (MCU) (Correct Answer)
- D. Intravenous Pyelography
Explanation: ***Micturating Cystourethrography (MCU)*** - The **Micturating Cystourethrography (MCU)** is the gold standard for diagnosing posterior urethral valves (PUV) as it directly visualizes the posterior urethra during voiding. - It classically shows a **dilated posterior urethra** with a narrow opening at the level of the valves, often accompanied by **vesicoureteral reflux** and bladder wall abnormalities. *Ultrasound* - **Antenatal ultrasound** can suggest PUV by showing bilateral **hydronephrosis**, a dilated bladder, and thick-walled bladder with a "keyhole sign" (dilated posterior urethra). - However, ultrasound alone **cannot definitively diagnose** the valves or rule out other causes of obstruction. *Retrograde urethrography* - **Retrograde urethrography (RGU)** involves injecting contrast against the flow of urine, which can mask the presence of posterior urethral valves, as they are typically obstructive to antegrade flow. - While RGU can highlight urethral strictures and other anterior urethral pathologies, it is **not ideal** for visualizing posterior urethral valves. *Intravenous Pyelography* - **Intravenous Pyelography (IVP)** assesses kidney function and the collecting system, but it provides **limited detailed visualization** of the urethra itself. - While it might show features of obstructive uropathy like **hydronephrosis** or delayed excretion, it cannot directly confirm the presence or location of posterior urethral valves.
Question 6: Blood testis barrier in testis is formed by?
- A. Germ cells
- B. Sertoli cells (Correct Answer)
- C. Leydig cells
- D. Granulosa cells
Explanation: ***Sertoli cells*** - **Sertoli cells** form tight junctions with each other, creating the **blood-testis barrier** [1] - This barrier divides the seminiferous epithelium into **basal and adluminal compartments** [1] - Essential for protecting developing **germ cells** from immune attack and maintaining a specialized microenvironment for **spermatogenesis** [1] - The tight junctions between Sertoli cells are among the tightest in the human body *Granulosa cells* - **Granulosa cells** are found in the **ovary**, not the testis - They surround the oocyte in ovarian follicles and produce **estrogen** - Completely unrelated to testicular structure or function *Germ cells* - **Germ cells** (spermatogonia, spermatocytes, spermatids, spermatozoa) are the developing sperm cells [1] - They are **protected by** the blood-testis barrier, not forming it [1] - Located within the seminiferous tubules but do not create barrier structures [1] *Leydig cells* - **Leydig cells** are interstitial cells located in the connective tissue **between seminiferous tubules** - Their primary function is production of **testosterone**, not forming barriers [2] - They are outside the seminiferous tubules and not involved in barrier formation [2]
Question 7: Remnants of Wolffian ducts in a female are found in
- A. Broad ligament (Correct Answer)
- B. Uterovesical pouch
- C. Pouch of Douglas
- D. Iliac fossa
Explanation: ***Broad ligament*** - In females, remnants of the **Wolffian (mesonephric) ducts** can persist as structures such as the **epoophoron**, **paroophoron**, and **Gartner's duct cysts**, which are typically found within the broad ligament [1]. - The **broad ligament** is a fold of peritoneum that extends from the lateral walls of the uterus to the sidewalls of the pelvis, enclosing these developmental remnants. *Uterovesical pouch* - This is a peritoneal reflection between the **uterus and the bladder** and does not typically contain remnants of the Wolffian ducts. - It is a common site for fluid accumulation but not for developmental anomalies related to the mesonephric system. *Pouch of Douglas* - Also known as the **recto-uterine pouch**, this is the most dependent part of the peritoneal cavity in females, located between the **uterus and the rectum**. - While it can accumulate fluid or pathology, it is not where Wolffian duct remnants are primarily located. *Iliac fossa* - The **iliac fossa** contains structures like the **iliacus muscle**, **lymph nodes**, and parts of the bowel, but it is not the anatomical location for the remnants of the Wolffian ducts in females. - This region is more involved in supporting abdominal contents and housing major blood vessels and nerves rather than reproductive developmental remnants.
Question 8: Development of labia majora is from -
- A. Urogenital sinus
- B. Mullerian duct
- C. Genital ridge
- D. Genital swelling (Correct Answer)
Explanation: ***Genital swelling*** - The **labia majora** develop from the **genital (labioscrotal) swellings** in females, which are homologous to the scrotum in males [3]. - These swellings enlarge and fuse anteriorly to form the mons pubis and posteriorly to form the posterior commissures of the labia majora. *Urogenital sinus* - The **urogenital sinus** gives rise to structures like the **bladder**, **urethra**, and parts of the **vagina** in females [2]. - It does not contribute to the formation of the external labial structures. *Mullerian duct* - The **Mullerian (paramesonephric) ducts** develop into the **fallopian tubes**, **uterus**, and the **upper third of the vagina** [1], [2]. - These structures are internal reproductive organs and do not form external genitalia like the labia majora. *Genital ridge* - The **genital ridge** is the embryonic precursor to the **gonads** (ovaries or testes). - It differentiates into either ovaries or testes and does not directly form external genital structures.
Question 9: The nasopharynx is primarily lined by which type of epithelium?
- A. Stratified squamous keratinized
- B. Ciliated columnar (Correct Answer)
- C. Cuboidal
- D. Stratified squamous nonkeratinized
Explanation: ***Ciliated columnar*** - The **nasopharynx** is lined by **pseudostratified ciliated columnar epithelium** with goblet cells, also known as respiratory epithelium [2]. - This specialized epithelium is crucial for **warming**, **humidifying**, and **filtering** inhaled air before it reaches the lungs [1]. *Stratified squamous nonkeratinized* - This type of epithelium is found in areas subject to **abrasion** and needing protection, such as the **oral cavity**, pharynx (oropharynx and laryngopharynx), and esophagus. - It is not primary in the nasopharynx, which requires ciliary action for particle removal. *Stratified squamous keratinized* - This robust epithelium is characteristic of areas that require significant **protection against friction** and **drying**, such as the **epidermis of the skin**. - It is not found in the nasopharynx due to its lack of flexibility and ciliary function. *Cuboidal* - **Cuboidal epithelium** is typically found in glands and kidney tubules, where its function includes **secretion** and **absorption**. - It lacks the specialized cilia and goblet cells necessary for the respiratory function of the nasopharynx [2].
Question 10: Which artery supplies the ductus deferens?
- A. Deferential artery (Correct Answer)
- B. Cremasteric artery
- C. Inferior epigastric artery
- D. Vesical artery
Explanation: ***Deferential artery*** - The **deferential artery** is the primary blood supply to the **ductus deferens**. It typically originates from the **superior or inferior vesical artery**. - This artery runs alongside the ductus deferens within the **spermatic cord**, providing arterial branches throughout its length. *Cremasteric artery* - The **cremasteric artery** primarily supplies the **cremaster muscle** and the fascial coverings of the spermatic cord [1]. - While it traverses the spermatic cord, it does not directly supply the ductus deferens itself. *Inferior epigastric artery* - The **inferior epigastric artery** supplies the **anterior abdominal wall muscles** and skin [1]. - It does not directly supply the ductus deferens but gives rise to the **cremasteric artery** as one of its branches [1]. *Vesical artery* - The **vesical arteries** (superior and inferior) primarily supply the **urinary bladder**. - While the deferential artery often originates from a vesical artery, "vesical artery" itself is not the direct and specific supply to the ductus deferens.
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