USMLE Step 1 Reproductive Practice Questions

In the male reproductive system, which cells are responsible for producing testosterone in response to stimulation by Luteinizing Hormone (LH)?

• (A) Leydig cells (Interstitial cells)
• (B) Sertoli cells
• (C) Spermatogonia
• (D) Epididymal cells

Which hormone is primarily responsible for inducing the proliferative phase of the endometrium during the first half of the menstrual cycle?

• (A) Estrogen
• (B) Progesterone
• (C) Follicle-stimulating hormone (FSH)
• (D) Luteinizing hormone (LH)

What is the function of Sertoli cells in the seminiferous tubules?

• (A) Support spermatogenesis, form blood-testis barrier, secrete inhibin B and androgen-binding protein (ABP)
• (B) Produce testosterone
• (C) Undergo meiosis to form sperm
• (D) Store mature sperm

The surge of which hormone is the most direct trigger for ovulation?

• (A) Luteinizing hormone (LH)
• (B) Follicle-stimulating hormone (FSH)
• (C) Estradiol
• (D) Progesterone

Where does fertilization typically occur?

• (A) Ampulla of the fallopian tube (uterine tube)
• (B) Uterus
• (C) Ovary
• (D) Vagina

Which hormone, produced by the corpus luteum, is essential for maintaining the secretory endometrium and supporting early pregnancy?

• (A) Progesterone
• (B) Estrogen
• (C) Inhibin A
• (D) Human chorionic gonadotropin (hCG)

What is the chromosomal composition of Turner syndrome?

• (A) 45,X
• (B) 47,XXY
• (C) 47,XYY
• (D) 46,XX with SRY translocation

Which structure is responsible for producing human chorionic gonadotropin (hCG) early in pregnancy to maintain the corpus luteum?

• (A) Syncytiotrophoblast of the placenta
• (B) Cytotrophoblast of the placenta
• (C) Corpus luteum itself
• (D) Decidua

What is the mechanism of action of combined oral contraceptive pills (OCPs) containing estrogen and progestin?

• (A) Suppression of ovulation by inhibiting GnRH, LH, and FSH release; thickening of cervical mucus
• (B) Blocking sperm entry into the uterus
• (C) Inducing premature menstruation
• (D) Preventing implantation directly

In which phase of the ovarian cycle does the corpus luteum degenerate if fertilization does not occur?

• (A) Late luteal phase
• (B) Follicular phase
• (C) Ovulation
• (D) Early luteal phase

Which enzyme converts testosterone to the more potent androgen, dihydrotestosterone (DHT), in target tissues?

• (A) 5-alpha-reductase
• (B) Aromatase
• (C) 17-beta-hydroxysteroid dehydrogenase
• (D) Desmolase

Polycystic Ovary Syndrome (PCOS) is often associated with which hormonal imbalance?

• (A) Elevated LH/FSH ratio, insulin resistance, and hyperandrogenism
• (B) Low estrogen and high FSH
• (C) High progesterone and low LH
• (D) Isolated hyperprolactinemia

What is the primary source of estrogen after menopause?

• (A) Peripheral conversion of adrenal androgens in adipose tissue
• (B) Ovaries
• (C) Adrenal cortex directly
• (D) Anterior pituitary

Which substance, secreted by Sertoli cells, provides negative feedback specifically for FSH secretion from the anterior pituitary?

• (A) Inhibin B
• (B) Testosterone
• (C) Androgen-binding protein (ABP)
• (D) Müllerian inhibiting substance (MIS)

What is the term for the onset of the first menstrual period?

• (A) Menarche
• (B) Thelarche
• (C) Pubarche
• (D) Adrenarche

During pregnancy, which hormone is primarily responsible for stimulating the growth and development of the mammary glands?

• (A) Estrogen, Progesterone, Prolactin, and Human placental lactogen (hPL)
• (B) Oxytocin only
• (C) FSH only
• (D) LH only

Klinefelter syndrome is characterized by which chromosomal abnormality and phenotype?

• (A) 47,XXY; Male phenotype with tall stature, gynecomastia, small testes, infertility
• (B) 45,X; Female phenotype with short stature, streak ovaries
• (C) 47,XYY; Male phenotype, often tall, may have acne/behavioral issues
• (D) 46,XY with androgen insensitivity; Female external phenotype, male genotype

Which part of the sperm contains enzymes, like hyaluronidase and acrosin, necessary to penetrate the zona pellucida of the oocyte?

• (A) Acrosome
• (B) Midpiece
• (C) Tail (Flagellum)
• (D) Nucleus

What is the function of Müllerian inhibiting substance (MIS), also known as anti-Müllerian hormone (AMH), secreted by fetal Sertoli cells?

• (A) Causes regression of the Müllerian (paramesonephric) ducts in male fetuses
• (B) Causes development of the Wolffian (mesonephric) ducts
• (C) Stimulates testosterone production
• (D) Induces descent of the testes

Cryptorchidism refers to:

• (A) Failure of one or both testes to descend into the scrotum
• (B) Absence of testes
• (C) Inflammation of the testes
• (D) Twisting of the spermatic cord

The process by which spermatids undergo morphological changes to become mature spermatozoa (sperm) is called:

• (A) Spermiogenesis
• (B) Spermatogenesis
• (C) Meiosis I
• (D) Meiosis II

Which ligament contains the ovarian vessels (artery and vein) and nerves?

• (A) Suspensory ligament of the ovary (Infundibulopelvic ligament)
• (B) Ovarian ligament
• (C) Broad ligament
• (D) Round ligament of the uterus

Gestational diabetes mellitus is most often diagnosed during pregnancy based on results from which test?

• (A) Oral glucose tolerance test (OGTT)
• (B) Fasting plasma glucose
• (C) Hemoglobin A1c (HbA1c)
• (D) Random plasma glucose

Which hormone, structurally similar to GH and prolactin, is secreted by the placenta and has anti-insulin effects, contributing to maternal insulin resistance during pregnancy?

• (A) Human placental lactogen (hPL) / Human chorionic somatomammotropin (hCS)
• (B) Human chorionic gonadotropin (hCG)
• (C) Progesterone
• (D) Estriol

A complete hydatidiform mole typically has which karyotype and origin?

• (A) 46,XX (entirely paternal origin)
• (B) 46,XY (entirely paternal origin)
• (C) 69,XXY (triploid)
• (D) 45,X

Which phase of the uterine (menstrual) cycle corresponds to the ovarian luteal phase?

• (A) Secretory phase
• (B) Proliferative phase
• (C) Menstrual phase
• (D) Ischemic phase

Benign Prostatic Hyperplasia (BPH) involves proliferation of which elements in the prostate gland, primarily in the transitional zone?

• (A) Epithelial and stromal elements
• (B) Smooth muscle only
• (C) Glandular elements only
• (D) Connective tissue only

What is the primary mechanism of action of selective estrogen receptor modulators (SERMs) like tamoxifen?

• (A) Acts as an estrogen agonist in some tissues (e.g., bone, endometrium) and an antagonist in others (e.g., breast)
• (B) Blocks estrogen synthesis
• (C) Blocks androgen receptors
• (D) Stimulates progesterone receptors

What is the source and function of Gonadotropin-Releasing Hormone (GnRH)?

• (A) Hypothalamus; stimulates FSH and LH release from anterior pituitary
• (B) Anterior pituitary; stimulates gonads
• (C) Pineal gland; regulates sleep cycles
• (D) Adrenal cortex; regulates stress response

Which female reproductive structure is homologous to the male scrotum?

• (A) Labia majora
• (B) Labia minora
• (C) Clitoris
• (D) Vestibular bulbs

Oxytocin release from the posterior pituitary is stimulated by:

• (A) Suckling during breastfeeding and cervical/uterine stretch during labor
• (B) High estrogen levels
• (C) Low progesterone levels
• (D) ACTH

What change occurs in the oocyte immediately after fertilization by a sperm?

• (A) Completion of Meiosis II and formation of the ovum and second polar body
• (B) Completion of Meiosis I
• (C) Initiation of Meiosis I
• (D) Formation of the primary oocyte

Which condition involves the presence of endometrial glands and stroma outside the uterine cavity?

• (A) Endometriosis
• (B) Adenomyosis
• (C) Leiomyoma (fibroid)
• (D) Endometrial hyperplasia

What is the role of androgen-binding protein (ABP) secreted by Sertoli cells?

• (A) Binds testosterone, concentrating it within the seminiferous tubules
• (B) Transports testosterone in the blood
• (C) Stimulates Leydig cell function
• (D) Inhibits FSH release

During which stage of meiosis are primary oocytes arrested from fetal life until puberty?

• (A) Prophase I
• (B) Metaphase II
• (C) Prophase II
• (D) Metaphase I

What is the most common cause of primary amenorrhea in a patient with normal secondary sexual characteristics?

• (A) Müllerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome)
• (B) Turner syndrome (45,X)
• (C) Androgen insensitivity syndrome
• (D) Kallmann syndrome

Where are sperm stored and undergo final maturation (acquiring motility and fertilizing capacity)?

• (A) Epididymis
• (B) Seminiferous tubules
• (C) Vas deferens
• (D) Seminal vesicles

Human Papillomavirus (HPV), particularly high-risk types like 16 and 18, is strongly associated with the development of which cancer?

• (A) Cervical cancer
• (B) Ovarian cancer
• (C) Endometrial cancer
• (D) Vulvar cancer

Pre-eclampsia is a pregnancy-specific syndrome characterized by new-onset hypertension and usually proteinuria after 20 weeks of gestation. It is thought to be related to abnormal development of which structure?

• (A) Placental spiral arteries
• (B) Fetal kidneys
• (C) Maternal liver
• (D) Fetal heart

What is the function of the prostate gland secretion?

• (A) Contributes an alkaline, milky fluid containing citrate and prostate-specific antigen (PSA) to the semen
• (B) Produces thick, fructose-rich fluid for energy
• (C) Secretes lubricating mucus
• (D) Stores sperm