Reproductive system overview US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Reproductive system overview. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Reproductive system overview US Medical PG Question 1: A 27-year-old man comes to the physician with his wife because they have been unable to conceive. They have had regular unprotected sex for the past 18 months without using contraception. His wife has been tested and is fertile. The patient began puberty at the age of 13 years. He has been healthy except for an infection with Chlamydia trachomatis 10 years ago, which was treated with azithromycin. He is a professional cyclist and trains every day for 3–4 hours. His wife reports that her husband has often been stressed since he started to prepare for the national championships a year ago and is very conscious about his diet. His temperature is 36.5°C (97.7°F), pulse is 50/min, and blood pressure is 154/92 mm Hg. Physical examination of the husband shows an athletic stature with uniform inflammatory papular eruptions of the face, back, and chest. Genital examination shows small testes. Which of the following is the most likely underlying cause of this patient's infertility?
- A. Heat from friction
- B. Psychogenic erectile dysfunction
- C. Kallmann syndrome
- D. Anorexia nervosa
- E. Anabolic steroid use (Correct Answer)
Reproductive system overview Explanation: ***Anabolic steroid use***
- The patient's **athletic stature**, **inflammatory papular eruptions** (acne), **small testes**, and dedication to intense training are highly suggestive of anabolic steroid use. Anabolic steroids suppress endogenous **gonadotropin-releasing hormone (GnRH)**, leading to secondary hypogonadism, testicular atrophy, and infertility.
- The history of **Chlamydia trachomatis** 10 years ago is less likely to be the primary cause of current infertility given the effective treatment, and the associated signs point more strongly to steroid use.
*Heat from friction*
- While prolonged cycling can increase **scrotal temperature**, potentially affecting **sperm quality**, it is unlikely to cause the severe **testicular atrophy** and broad systemic effects (acne, hypertension) seen in this patient.
- **Infertility related to heat** typically presents as reduced sperm count or motility, without the endocrine disruptions associated with anabolic steroids.
*Psychogenic erectile dysfunction*
- **Erectile dysfunction** is not explicitly mentioned as a complaint; the primary concern is infertility despite regular unprotected sex. While stress can contribute to ED, it does not explain the **small testes** or systemic dermatological findings.
- **Psychogenic factors** primarily affect the ability to achieve or maintain an erection, not necessarily **sperm production** or testicular size in the absence of other hormonal issues.
*Kallmann syndrome*
- **Kallmann syndrome** is a genetic condition characterized by hypogonadotropic hypogonadism and **anosmia** (inability to smell) due to defective migration of GnRH neurons. Patients typically present with **delayed puberty** (primary amenorrhea in females, lack of secondary sexual characteristics in males).
- This patient began puberty at age 13, which is within the normal range, and there is no mention of anosmia, making Kallmann syndrome unlikely.
*Anorexia nervosa*
- Anorexia nervosa can lead to **hypogonadism** (due to low GnRH output from caloric restriction and excessive exercise), which might cause small testes and infertility. However, it is typically associated with **low body weight**, which contradicts the patient's athletic stature and professional cyclist status.
- While extreme dieting is mentioned, it's in the context of professional cycling, and the other symptoms like **acne** and **hypertension** are not typical findings in anorexia nervosa.
Reproductive system overview US Medical PG Question 2: A 32-year-old man presents to his primary care physician complaining of pain accompanied by a feeling of heaviness in his scrotum. He is otherwise healthy except for a broken arm he obtained while skiing several years ago. Physical exam reveals an enlarged “bag of worms” upon palpation of the painful scrotal region. Shining a light over this area shows that the scrotum does not transilluminate. Which of the following statements is true about the most likely cause of this patient's symptoms?
- A. Equally common on both sides
- B. More common on left due to drainage into renal vein (Correct Answer)
- C. More common on right due to drainage into renal vein
- D. More common on right due to drainage into inferior vena cava
- E. More common on left due to drainage into inferior vena cava
Reproductive system overview Explanation: ***More common on left due to drainage into renal vein***
- The patient's symptoms of scrotal pain, "bag of worms" on palpation, and lack of transillumination are classic for a **left-sided varicocele**.
- The longer course and perpendicular drainage of the **left testicular vein** into the left renal vein create higher pressure, making varicocele formation more common on the left.
*Equally common on both sides*
- Varicoceles are distinctly asymmetrical, with a well-established higher incidence on the left side due to anatomical differences.
- Bilateral varicoceles can occur but are less common than isolated left-sided ones and do not support an "equally common" distribution.
*More common on right due to drainage into renal vein*
- The right testicular vein typically drains directly into the **inferior vena cava (IVC)**, not the renal vein, which is a lower pressure system compared to the left.
- Therefore, anatomical factors do not favor varicocele formation on the right side due to drainage into the renal vein.
*More common on right due to drainage into inferior vena cava*
- While the right testicular vein drains into the IVC, this direct drainage path is associated with good venous return and a lower risk of varicocele.
- A right-sided varicocele is less common and, if present, should prompt investigation for retroperitoneal mass obstructing the IVC or right testicular vein.
*More common on left due to drainage into inferior vena cava*
- The left testicular vein typically drains into the **left renal vein**, not directly into the inferior vena cava.
- This anatomical description is incorrect and does not explain the higher incidence of left-sided varicoceles.
Reproductive system overview US Medical PG Question 3: A group of scientists developed a mouse model to study nondisjunction in meiosis. Their mouse model produced gametes in the following ratio: 2 gametes with 24 chromosomes each and 2 gametes with 22 chromosomes each. In which of the following steps of meiosis did the nondisjunction occur?
- A. Telophase I
- B. Metaphase II
- C. Anaphase I (Correct Answer)
- D. Anaphase II
- E. Metaphase I
Reproductive system overview Explanation: ***Anaphase I***
- Nondisjunction during **Anaphase I** occurs when homologous chromosomes fail to separate properly, meaning both homologs of a chromosome pair go to the same pole.
- This results in two secondary gametocytes with abnormal chromosome numbers: one with n+1 chromosomes (24) and one with n-1 chromosomes (22).
- When meiosis II proceeds normally, each abnormal secondary gametocyte divides to produce 2 identical gametes, resulting in **all 4 gametes being abnormal** in a 2:2 ratio (two n+1 and two n-1), matching the observed pattern.
*Telophase I*
- **Telophase I** is the final stage of meiosis I where chromosomes arrive at the poles and the cell divides, but it's not where the initial separation error (nondisjunction) occurs.
- Nondisjunction happens due to a failure of **chromosome segregation**, which is a process of anaphase, not telophase.
*Metaphase II*
- **Metaphase II** involves the alignment of sister chromatids at the metaphase plate in secondary gametocytes. Nondisjunction at this stage would involve sister chromatids failing to separate.
- Nondisjunction in Metaphase II (or Anaphase II) would lead to 2 normal gametes (23 chromosomes), one gamete with n+1 (24 chromosomes), and one gamete with n-1 (22 chromosomes), which differs from the given ratio.
*Anaphase II*
- **Nondisjunction in Anaphase II** would involve the failure of sister chromatids to separate in one of the secondary gametocytes.
- This would produce two normal gametes (23 chromosomes), one gamete with 24 chromosomes (n+1), and one gamete with 22 chromosomes (n-1), which is not the 2:2 ratio observed.
*Metaphase I*
- **Metaphase I** is characterized by the alignment of homologous chromosome pairs at the metaphase plate. While an issue here could precede nondisjunction, the actual event of failed separation occurs during anaphase.
- No separation of chromosomes occurs in Metaphase I; it is the stage of **chromosome alignment** before segregation.
Reproductive system overview US Medical PG Question 4: At postpartum physical examination, a newborn is found to have male external genitalia. Scrotal examination shows a single palpable testicle in the right hemiscrotum. Ultrasound of the abdomen and pelvis shows an undescended left testis, seminal vesicles, uterus, and fallopian tubes. Chromosomal analysis shows a 46, XY karyotype. Which of the following sets of changes is most likely to be found in this newborn?
Legend: Normal = normal levels, ↑ = increased levels, ↓ = decreased levels
SRY-gene activity | Müllerian inhibitory factor (MIF) | Testosterone | Dihydrotestosterone (DHT)
- A. Normal normal normal ↓
- B. ↓ ↓ ↓ ↓
- C. Normal ↓ normal normal (Correct Answer)
- D. ↓ ↓ normal normal
- E. Normal normal ↑ ↑
Reproductive system overview Explanation: ***Normal ↓ Normal Normal***
- A 46, XY karyotype with male external genitalia indicates **normal SRY-gene activity** and normal **testosterone** production, as these are critical for male sexual differentiation.
- The presence of a **uterus and fallopian tubes** in a 46, XY individual is characteristic of persistent **Müllerian duct syndrome**, caused by a **deficiency or insensitivity to Müllerian Inhibiting Factor (MIF)**, leading to a decreased level of MIF.
*Normal Normal Normal ↓*
- This pattern would suggest normal initial male differentiation but an issue downstream, possibly with **5-alpha-reductase deficiency** (leading to decreased DHT) and normal MIF, which would prevent Müllerian structure development.
- The presence of a **uterus and fallopian tubes** contradicts normal MIF levels.
*↓ ↓ ↓ ↓*
- This combination indicates severe defects in all aspects of male sexual development, which would lead to **female external genitalia** or ambiguous genitalia, not male external genitalia.
- Such low levels would also prevent the formation of a palpable testis, and a 46, XY karyotype with female internal structures due to low testosterone and MIF would be highly unlikely to produce male external genitalia.
*↓ ↓ Normal Normal*
- While low MIF would explain the presence of a uterus and fallopian tubes, a **decreased SRY-gene activity** would prevent the development of testes and lead to ambiguous or female external genitalia, rather than male external genitalia.
- Normal testosterone and DHT with decreased SRY gene activity is a contradictory combination, as testosterone production is dependent on the presence of testes.
*Normal Normal ↑ ↑*
- This profile would result in normal male internal and external genitalia, without the presence of **uterus or fallopian tubes**.
- Increased levels of androgens are typically found in conditions like **congenital adrenal hyperplasia** in XX individuals, leading to virilization, but are not consistent with the internal structures seen here.
Reproductive system overview US Medical PG Question 5: A researcher is studying the effects of hormones on different cells within the ovarian follicle. She adds follicle stimulating hormone (FSH) to a culture of ovarian follicle cells. She then measures the activity levels of different enzymes within the cells. Which enzyme and ovarian cell type would be expected to be stimulated by the addition of FSH?
- A. Desmolase; theca interna cell
- B. Aromatase; theca externa cell
- C. Aromatase; granulosa cell (Correct Answer)
- D. Desmolase; granulosa cell
- E. Aromatase; theca interna cell
Reproductive system overview Explanation: ***Aromatase; granulosa cell***
- **FSH** acts directly on **granulosa cells** to stimulate their proliferation and differentiation.
- One of the key functions of stimulated granulosa cells is the production of **aromatase**, an enzyme responsible for converting **androgens** (produced by theca cells) into **estrogens**.
*Desmolase; theca interna cell*
- **Desmolase** (specifically cholesterol desmolase, or CYP11A1) is found in **theca interna cells** and is responsible for converting cholesterol into **androgens**.
- Theca interna cell activity, including desmolase, is primarily stimulated by **LH**, not FSH.
*Aromatase; theca externa cell*
- The **theca externa cells** are primarily connective tissue and lack significant endocrine function, including aromatase activity.
- **Aromatase** is predominantly present in the granulosa cells.
*Desmolase; granulosa cell*
- While granulosa cells are crucial for estrogen synthesis via aromatase, they do not produce **desmolase**.
- **Desmolase** is the key enzyme in theca interna cells for androgen synthesis.
*Aromatase; theca interna cell*
- **Theca interna cells** produce **androgens** under the influence of **LH** and do not express **aromatase**.
- **Aromatase** is exclusively expressed in the **granulosa cells** and converts these androgens into estrogens.
Reproductive system overview US Medical PG Question 6: A 25-year-old male visits his physician because of fertility issues with his wife. Physical exam reveals bilateral gynecomastia, elongated limbs, and shrunken testicles. Levels of plasma gonadotropins are elevated. Which of the following is also likely to be increased in this patient:
- A. Testosterone
- B. Inhibin
- C. Sertoli cells
- D. Ejaculatory sperm
- E. Aromatase (Correct Answer)
Reproductive system overview Explanation: ***Correct: Aromatase***
- The symptoms described (gynecomastia, elongated limbs, shrunken testicles, elevated gonadotropins) are characteristic of **Klinefelter syndrome (47, XXY)**.
- In Klinefelter syndrome, **increased aromatase activity** (particularly in adipose tissue) leads to enhanced conversion of androgens to estrogens, resulting in elevated estrogen levels.
- This increased estrogen contributes to gynecomastia and exacerbates the hypogonadism and fertility issues.
*Incorrect: Testosterone*
- In Klinefelter syndrome, **testosterone levels are typically low** due to primary testicular failure, which explains the shrunken testicles and infertility.
- The elevated gonadotropins (LH and FSH) are a compensatory response to the low testosterone.
*Incorrect: Inhibin*
- **Inhibin** is produced by **Sertoli cells** and normally suppresses FSH release.
- In Klinefelter syndrome, damage to the seminiferous tubules and impaired Sertoli cell function lead to **decreased inhibin production**, contributing to elevated FSH.
*Incorrect: Sertoli cells*
- Klinefelter syndrome is characterized by **dysgenesis and reduced numbers of Sertoli cells** within the seminiferous tubules, leading to impaired spermatogenesis and fertility issues.
- This reduction in Sertoli cells also contributes to decreased inhibin levels.
*Incorrect: Ejaculatory sperm*
- Individuals with Klinefelter syndrome typically have **azoospermia** or severe oligozoospermia due to profound testicular dysfunction and seminiferous tubule atrophy.
- This significantly impairs their fertility and is a common reason for presenting with infertility.
Reproductive system overview US Medical PG Question 7: A researcher is studying gamete production and oogenesis. For her experiment, she decides to cultivate primary oocytes in their arrested state and secondary oocytes just prior to fertilization. When she examines these gametes, she will find that the primary oocytes and secondary oocytes are arrested in which phases of meiosis, respectively?
- A. Anaphase I; anaphase II
- B. Interphase I; prophase II
- C. Metaphase I; metaphase II
- D. Metaphase I; prophase II
- E. Prophase I; metaphase II (Correct Answer)
Reproductive system overview Explanation: ***Prophase I; metaphase II***
- **Primary oocytes** are arrested in **prophase I** from embryonic development until puberty, when they resume meiosis in preparation for ovulation.
- **Secondary oocytes** are immediately arrested in **metaphase II** after completing meiosis I, and they will remain in this stage until fertilization occurs.
*Anaphase I; anaphase II*
- **Anaphase I** involves the separation of **homologous chromosomes**, and **anaphase II** involves the separation of **sister chromatids**. Neither primary nor secondary oocytes are arrested in these stages.
- Meiotic arrest occurs at earlier stages to prevent further division until specific triggers (ovulation or fertilization) are met.
*Interphase I; prophase II*
- **Interphase I** precedes meiosis I, during which DNA replication occurs, and it is not a stage of meiotic arrest for primary oocytes.
- **Prophase II** is a transient stage in meiosis II, and secondary oocytes are arrested later in **metaphase II**, not prophase II.
*Metaphase I; metaphase II*
- While **secondary oocytes** are indeed arrested in **metaphase II**, **primary oocytes** are arrested much earlier in **prophase I**, not metaphase I.
- The arrest in metaphase I is temporary for primary oocytes as they complete meiosis I to form secondary oocytes upon hormonal signaling.
*Metaphase I; prophase II*
- **Primary oocytes** are arrested in **prophase I**, not metaphase I. Meiosis I is completed before ovulation, leading to the formation of secondary oocytes.
- **Secondary oocytes** are arrested in **metaphase II**, not prophase II, awaiting fertilization to complete meiosis II.
Reproductive system overview US Medical PG Question 8: Linear growth of bone is disturbed when a fracture occurs in which part?
- A. Epiphysis
- B. Diaphysis
- C. Metaphysis
- D. Epiphyseal plate (Correct Answer)
- E. Periosteum
Reproductive system overview Explanation: ***Epiphyseal plate***
- The **epiphyseal plate**, also known as the **growth plate**, is a cartilaginous disc responsible for the **longitudinal growth** of long bones.
- A fracture in this region can damage the **chondrocytes** and disrupt the normal process of endochondral ossification, leading to **growth arrest** or limb length discrepancy.
*Epiphysis*
- The **epiphysis** is the end part of a long bone, often covered by **articular cartilage**, forming a joint.
- While an epiphyseal fracture can affect joint function, it typically does not directly disturb the **linear growth** of the bone unless it extends into the growth plate.
*Diaphysis*
- The **diaphysis** is the main or midsection of a long bone, composed primarily of **compact bone**.
- Fractures in the diaphysis generally heal through **callus formation** and remodeling, usually without significantly impacting the overall **linear growth** of the bone.
*Metaphysis*
- The **metaphysis** is the wider portion of a long bone, adjacent to the growth plate and diaphysis.
- Though highly vascular, fractures to the metaphysis usually heal well and do not directly control **linear bone growth** like the epiphyseal plate.
*Periosteum*
- The **periosteum** is the fibrous membrane covering the outer surface of bones, important for **appositional growth** (bone widening) and fracture healing.
- While it contains osteogenic cells that contribute to bone repair and thickness, it does not control **longitudinal bone growth**, which is the function of the epiphyseal plate.
Reproductive system overview US Medical PG Question 9: A 14-year-old boy is brought to the physician for the evaluation of back pain for the past six months. The pain is worse with exercise and when reclining. He attends high school and is on the swim team. He also states that he lifts weights on a regular basis. He has not had any trauma to the back or any previous problems with his joints. He has no history of serious illness. His father has a disc herniation. Palpation of the spinous processes at the lumbosacral area shows that two adjacent vertebrae are displaced and are at different levels. Muscle strength is normal. Sensation to pinprick and light touch is intact throughout. When the patient is asked to walk, a waddling gait is noted. Passive raising of either the right or left leg causes pain radiating down the ipsilateral leg. Which of the following is the most likely diagnosis?
- A. Spondylolisthesis (Correct Answer)
- B. Overuse injury
- C. Ankylosing spondylitis
- D. Disc herniation
- E. Facet joint syndrome
Reproductive system overview Explanation: ***Spondylolisthesis***
- The patient presents with **back pain worse with exercise and reclining**, along with **palpable displacement of adjacent vertebrae** at different levels, which are classic signs of spondylolisthesis. The **waddling gait** and pain radiating down the leg upon passive leg raising (suggesting nerve root irritation) further support this diagnosis.
- Spondylolisthesis, particularly **isthmic type**, is common in adolescent athletes involved in sports like swimming and weightlifting due to repetitive hyperextension leading to stress fractures in the pars interarticularis.
*Overuse injury*
- While overuse injuries are common in athletes, they typically present with generalized pain or tenderness in the affected area without distinct **vertebral displacement** or neurological signs like radiating pain and a waddling gait.
- The specific signs of palpable vertebral displacement and nerve root irritation point to a more severe structural issue than a simple overuse soft tissue injury.
*Ankylosing spondylitis*
- **Ankylosing spondylitis** usually presents with **inflammatory back pain** that improves with exercise, not worsens, and often affects young adults, not typically a 14-year-old with these specific physical findings.
- It would not explain the **palpable vertebral displacement** or the sudden onset of neurological symptoms like radiating leg pain and waddling gait.
*Disc herniation*
- While disc herniation can cause **radiating leg pain** and back pain, it typically doesn't present with **palpable vertebral displacement** or a waddling gait in an adolescent without a history of significant trauma.
- The physical exam finding of displaced vertebrae is more indicative of a structural instability like spondylolisthesis rather than an isolated disc problem, even though a father has a history.
*Facet joint syndrome*
- Facet joint syndrome usually results in localized back pain that **worsens with extension and rotation** but typically does not cause **palpable vertebral displacement** or neurological deficits like radiating pain and a waddling gait.
- It is also more common in older adults due to degenerative changes, rather than a 14-year-old athlete.
Reproductive system overview US Medical PG Question 10: A 53-year-old man with a history of alcoholic liver cirrhosis was admitted to the hospital with ascites and general wasting. He has a history of 3-5 ounces of alcohol consumption per day for 20 years and 20-pack-year smoking history. Past medical history is significant for alcoholic cirrhosis of the liver, diagnosed 5 years ago. On physical examination, the abdomen is firm and distended. There is mild tenderness to palpation in the right upper quadrant with no rebound or guarding. Shifting dullness and a positive fluid wave is present. Prominent radiating umbilical varices are noted. Laboratory values are significant for the following:
Total bilirubin 4.0 mg/dL
Aspartate aminotransferase (AST) 40 U/L
Alanine aminotransferase (ALT) 18 U/L
Gamma-glutamyltransferase 735 U/L
Platelet count 11,000/mm3
WBC 4,300/mm3
Serology for viral hepatitis B and C are negative. A Doppler ultrasound of the abdomen shows significant enlargement of the epigastric superficial veins and hepatofugal flow within the portal vein. There is a large volume of ascites present. Paracentesis is performed in which 10 liters of straw-colored fluid is removed. Which of the following sites of the portocaval anastomosis is most likely to rupture and bleed first in this patient?
- A. Superior and middle rectal vein – inferior rectal veins
- B. Umbilical vein – superficial epigastric veins
- C. Esophageal branch of left gastric vein – esophageal branches of azygos vein (Correct Answer)
- D. Paraumbilical veins – inferior epigastric veins
- E. Short gastric veins – intercostal veins
Reproductive system overview Explanation: ***Esophageal branch of left gastric vein – esophageal branches of azygos vein***
- The gastroesophageal junction is the most frequent site of **life-threatening variceal bleeding** in patients with portal hypertension due to liver cirrhosis. The elevated portal pressure forces blood from the **left gastric (coronary) vein** into the thinner-walled esophageal veins which drain into the azygos system.
- The patient's history of **alcoholic liver cirrhosis** makes portal hypertension and subsequent esophageal varices highly likely. While other portocaval anastomoses exist, esophageal varices are clinically the most significant due to their propensity for rupture and severe hemorrhage.
*Superior and middle rectal vein – inferior rectal veins*
- This anastomosis concerns the rectums, involving the **superior rectal vein (portal system)** and the **middle/inferior rectal veins (systemic system)**.
- While portal hypertension can lead to **anorectal varices**, also known as hemorrhoids, these are less prone to life-threatening hemorrhage compared to esophageal varices and typically present with bleeding on defecation or discomfort.
*Umbilical vein – superficial epigastric veins*
- This anastomosis is responsible for the formation of a **caput medusae**, which is a sign of portal hypertension where prominent periumbilical veins radiate from the navel. The patient presents with prominent "radiating umbilical varices," which is consistent with this finding.
- While visually striking and indicative of portal hypertension, these superficial varices are generally **not associated with significant or life-threatening hemorrhage** compared to esophageal varices.
*Paraumbilical veins – inferior epigastric veins*
- The paraumbilical veins run within the falciform ligament and connect the portal system to the systemic circulation via the **epigastric veins**.
- This anastomosis contributes to the formation of caput medusae but is **not a common site for clinically significant bleeding** requiring intervention compared to esophageal varices.
*Short gastric veins – intercostal veins*
- The short gastric veins drain into the splenic vein (part of the portal system) and connect to systemic veins such as the intercostal veins via retroperitoneal anastomoses.
- While this is a potential site of portosystemic shunting, the short gastric veins are more commonly implicated in **gastric varices**, particularly in the fundus. However, gastric varices are less frequent and **rupture less commonly than esophageal varices**, although hemorrhage from them can be more severe when it does occur.
More Reproductive system overview US Medical PG questions available in the OnCourse app. Practice MCQs, flashcards, and get detailed explanations.
