5 questions · Follicle stages, hormones, 2-cell model, corpus luteum
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07:30
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Instructions: Select the single best answer for each question. Review your answers at the end of the block before proceeding.
Question 1 of 5 — Oocyte Meiotic Arrest
A 28-year-old woman undergoing IVF evaluation has her pre-ovulatory follicle aspirated after hCG trigger administration. The retrieved oocyte is examined under the microscope; chromatin analysis reveals the oocyte has completed meiosis I and arrested again. Which stage of meiosis is the oocyte currently in, and what intracellular factor maintains this arrest until fertilization?
AProphase I; maintained by oocyte meiosis inhibitor (OMI) in follicular fluid
BAnaphase I; maintained by cyclin B degradation
CMetaphase II; maintained by cytostatic factor (CSF) / high MPF activity
DTelophase II; maintained by nuclear envelope reformation
EInterphase; awaiting DNA replication after fertilization
C — Metaphase II (maintained by CSF/MPF). The complete meiotic sequence: Prophase I arrest at birth → follicular recruitment at puberty → transition to Prophase II arrest in antral follicle (OMI-mediated) → LH surge overrides OMI → meiosis resumes → completes meiosis I → arrests at metaphase II. Metaphase II arrest is maintained by cytostatic factor (CSF) keeping maturation-promoting factor (MPF) active. Only fertilization (calcium influx) can break metaphase II arrest → completion of meiosis II. OMI (A) arrests at prophase II earlier in development, not metaphase II.
Question 2 of 5 — 2-Cell Model of Steroidogenesis
A researcher isolates cells from a human pre-ovulatory Graafian follicle and cultures them with different hormones. Group 1 (theca interna cells) + LH produces compound X. When compound X is transferred to Group 2 (granulosa cells) + FSH, it is converted to estrogen. Which enzyme in Group 2 is responsible for this conversion, and what is compound X?
A5α-reductase; compound X is testosterone
BAromatase (CYP19); compound X is androstenedione
C21-hydroxylase; compound X is 17-OH-progesterone
DDesmolase; compound X is cholesterol
E11β-hydroxylase; compound X is 11-deoxycorticosterone
B — Aromatase; compound X is androstenedione. This is the classic 2-cell 2-gonadotropin model: LH stimulates THECA interna cells to produce androstenedione (from cholesterol via 17α-hydroxylase + 17,20-lyase; theca cells LACK aromatase). Androstenedione diffuses into GRANULOSA cells, where FSH-induced aromatase (CYP19) converts it to estrogen (estradiol). Granulosa cells lack the androgen-producing enzymes. This cross-talk is essential — neither cell can make estrogen alone. Clinical relevance: Aromatase inhibitors (letrozole, anastrozole) block granulosa conversion — used for ovulation induction in PCOS and postmenopausal ER+ breast cancer.
Question 3 of 5 — Corpus Luteum Hormone Switch
A 29-year-old woman's day-22 endometrial biopsy shows coiled, tortuous glands filled with glycogen-rich secretions. Her ovaries contain a large corpus luteum. The pathologist comments that granulosa lutein cells have taken on a NEW steroidogenic function distinct from their pre-ovulation role. Which of the following best describes this change?
AGranulosa cells continue producing estrogen; theca lutein cells now make progesterone
BGranulosa lutein cells now produce progesterone; theca lutein cells now produce estrogen
CGranulosa lutein cells stop all steroidogenesis; the oocyte itself secretes hormones
DBoth granulosa and theca lutein cells now produce only androgens
EGranulosa lutein cells now produce cortisol under LH stimulation
B — Progesterone from granulosa lutein; estrogen from theca lutein. After ovulation, the residual granulosa + theca cells "luteinize" and their hormone outputs swap. Granulosa lutein cells → progesterone (dominant); theca lutein cells → estrogen. This is the reverse of the pre-ovulation 2-cell model. Progesterone drives the secretory phase endometrium: glands become coiled/tortuous, spiral arteries elongate, glycogen-rich secretions for potential implantation. If pregnancy occurs, hCG (LH-like) from the syncytiotrophoblast rescues the CL. If not, the CL regresses → corpus albicans, P/E drop → menses.
Question 4 of 5 — LH Surge Physiology
A medical student reviewing the menstrual cycle notes that estrogen from the dominant follicle exerts negative feedback on the hypothalamus throughout the early follicular phase. Yet at mid-cycle, estrogen suddenly triggers a massive LH surge instead of inhibiting it. Which of the following best explains this apparently paradoxical switch?
AInhibin B from granulosa cells temporarily blocks the negative feedback loop
BRising progesterone from the corpus luteum removes estrogen's feedback
CSustained high estrogen above a critical threshold switches to positive feedback on the hypothalamus and pituitary
DFSH directly stimulates LH secretion at mid-cycle
EGnRH receptors on pituitary gonadotrophs downregulate
C — Estrogen threshold → positive feedback. Most of the menstrual cycle, estrogen exerts negative feedback on GnRH/LH/FSH. However, when estrogen reaches a sustained high level (typically >200 pg/mL for ~50 hours) from the dominant Graafian follicle, it paradoxically SWITCHES to POSITIVE feedback on the hypothalamus (↑ GnRH pulse frequency) and pituitary (↑ responsiveness) → the LH surge. This is the rising estrogen of Graafian follicle → LH surge → ovulation. Pharmacologically, clomiphene (SERM that blocks hypothalamic estrogen receptors) removes the estrogen signal → hypothalamus "senses" low estrogen → ↑ GnRH pulses → ↑ FSH → ovulation induction in PCOS.
Question 5 of 5 — Follicular Identification
An ovarian histology slide shows a follicle with an eccentrically located oocyte surrounded by a thin ring of granulosa cells, connected to the main follicular wall by a thicker stalk of granulosa cells. A large fluid-filled space dominates the center of the follicle. Well-defined theca interna and theca externa layers are visible at the periphery. Which structure directly surrounding the oocyte travels with it at ovulation?
ATheca interna cells
BZona pellucida alone (no cells)
CCorona radiata — innermost layer of granulosa cells
DCumulus oophorus — the stalk of granulosa cells
EBasal lamina of the granulosa layer
C — Corona radiata. This describes a Graafian (tertiary) follicle — the dominant pre-ovulatory follicle. Structures: antrum (large fluid-filled space), cumulus oophorus (granulosa stalk anchoring oocyte to follicle wall), corona radiata (innermost single layer of granulosa cells tightly surrounding the oocyte), zona pellucida (glycoprotein coat inside corona radiata), theca interna + externa (outside granulosa). At ovulation, the oocyte + zona pellucida + corona radiata are released together — the corona radiata must be "drilled through" by sperm (acrosome reaction) to access the zona pellucida and then the oocyte. Cumulus (D) anchors to the follicle wall; it does NOT travel with the oocyte.
Instructions: Select the single best answer for each question. Review your answers at the end of the block before proceeding.
Question 6 of 15 — Endometrial Histology
A 34-year-old woman undergoing workup for infertility has an endometrial biopsy on day 22 of her menstrual cycle. Histology demonstrates coiled, tortuous glands with vacuolated cells, prominent spiral arteries extending close to the surface, and edematous stroma. Serum progesterone at the time of biopsy is 15 ng/mL. Which of the following best describes the endocrine state responsible for these findings?
D — Mid-secretory (luteal) phase. Day 22 is mid-luteal. Coiled/tortuous glands + prominent spiral arteries + stromal edema + serum progesterone ~15 ng/mL = classic secretory phase signature driven by corpus luteum progesterone. The secretory phase readies the endometrium for implantation (~day 21–24 = "implantation window"). Contrast: proliferative phase shows straight tubular glands (not coiled) driven by estrogen. Late secretory / ischemic phase shows gland breakdown and spiral artery vasospasm as progesterone falls. Progesterone levels > 3–5 ng/mL confirm ovulation has occurred.
Question 7 of 15 — Asherman Syndrome
A 32-year-old G3P3 woman had a dilation and curettage (D&C) after a miscarriage 6 months ago. She has now developed secondary amenorrhea and inability to conceive. Hysteroscopy reveals intrauterine adhesions and scarring. Which of the following anatomic structures was most likely destroyed during her procedure, preventing normal endometrial regeneration?
AFunctionalis layer of the endometrium
BBasalis layer of the endometrium
CMyometrium
DPerimetrium
EMuscularis mucosae
B — Basalis layer. This is Asherman syndrome — intrauterine adhesions from trauma (D&C, infection, retained products of conception). The basalis is the deep layer of the endometrium that serves as the stem cell source for regenerating the functionalis each cycle. Supplied by straight arteries (not hormone-responsive). Destruction of the basalis → cannot regenerate functionalis → amenorrhea/hypomenorrhea + infertility. The functionalis (A) is what normally sheds with menses; its destruction doesn't cause Asherman because it would normally regrow. Tx: hysteroscopic adhesiolysis.
Question 8 of 15 — Cervical Cancer Mechanism
A 42-year-old woman has a Pap smear showing high-grade squamous intraepithelial lesion (HSIL). HPV testing is positive for HPV-16. Colposcopy with biopsy at the squamocolumnar junction confirms CIN III with carcinoma in situ. Which of the following molecular mechanisms best explains the loss of cell cycle control in her lesion?
AHPV E1 protein induces DNA hypermethylation of tumor suppressors
BHPV E6 promotes p53 degradation; HPV E7 inhibits Rb protein
CHPV capsid proteins L1/L2 directly bind to DNA polymerase
EHPV activates PI3K/AKT/mTOR signaling via receptor tyrosine kinase mutations
B — E6 degrades p53; E7 inhibits Rb. High-risk HPV types (16, 18, 31, 33, 45) encode two critical oncoproteins: E6 binds and promotes ubiquitin-mediated degradation of p53 — losing the G1 DNA-damage checkpoint. E7 binds Rb, displacing E2F transcription factors → unchecked G1/S progression. Loss of both tumor suppressors allows uncontrolled proliferation → CIN progression → invasive SCC. Location: transformation zone (squamocolumnar junction). L1 (C) is the capsid protein used to make Gardasil vaccine (L1-based VLPs). Prevention: Gardasil 9 (9–45 yo).
Question 9 of 15 — Adenomyosis
A 45-year-old G4P4 woman presents with progressively worsening heavy, painful menstrual periods over the past 2 years. Pelvic exam shows a diffusely enlarged, globular, boggy, and tender uterus. Pelvic MRI demonstrates thickening of the junctional zone with small cystic foci within the myometrium. Which of the following best describes the pathophysiology of her condition?
AEndometrial tissue outside the uterus (ovaries, peritoneum)
BEndometrial glands and stroma within the myometrium
CBenign smooth muscle tumors arising from myometrium
DMalignant proliferation of endometrial glands
EChronic infection with endomyometritis
B — Endometrial tissue within myometrium (adenomyosis). Buzzwords: multiparous woman ~ 40s, heavy painful menses, globular/boggy/tender uterus, thickened junctional zone on MRI. Adenomyosis = endometrial glands + stroma trapped WITHIN the myometrium (contrast to endometriosis = ectopic endometrium OUTSIDE uterus). These ectopic foci bleed with each menstrual cycle, causing dysmenorrhea and uterine enlargement. Definitive dx is post-hysterectomy histology. Fibroids (C) would give an irregularly enlarged uterus. Endometrial cancer (D) presents with postmenopausal bleeding. Tx: OCPs, IUD, hysterectomy (definitive).
Question 10 of 15 — Endometrial Cancer
A 62-year-old obese postmenopausal woman (BMI 36) with diabetes, hypertension, and nulliparity presents with 2 months of intermittent vaginal bleeding. Her last menstrual period was at age 54. She has taken tamoxifen for 4 years for ER+ breast cancer. Endometrial biopsy reveals well-differentiated endometrioid adenocarcinoma. Which of the following is the most important underlying mechanism for her endometrial cancer risk?
ADirect mutagenic effect of insulin on endometrial DNA
CAge-related accumulation of somatic p53 mutations as in Type II cancer
DMicrosatellite instability from Lynch syndrome (MLH1 germline)
EHPV infection of the endometrium
B — Chronic unopposed estrogen. Type I endometrial cancer (80%, endometrioid) is estrogen-driven, preceded by endometrial hyperplasia. Risk factors all share unopposed estrogen exposure: obesity (peripheral aromatization of androstenedione → estrone in adipose), nulliparity (more ovulatory cycles + unopposed proliferative stimulation), late menopause/early menarche, PCOS (anovulation), estrogen-only HRT, tamoxifen (uterine agonist while breast antagonist). Postmenopausal bleeding requires endometrial biopsy. Type II (C — serous/clear cell, p53-driven) is non-estrogen, worse prognosis. Lynch syndrome (D) is hereditary, usually earlier onset.
Block 3 — Gyn Pathology & Clinical Correlates
5 questions · PCOS, endometriosis, ovarian CA, ectopic pregnancy, breast CA
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07:30
Block Timer
Instructions: Select the single best answer for each question. These questions integrate multiple concepts from female reproductive pathology.
Question 11 of 15 — PCOS & Ovulation Induction
A 26-year-old woman with a BMI of 31 presents with 18 months of secondary infertility. Her cycles are 45–60 days. She has moderate facial hirsutism. Labs: LH 18, FSH 5 mIU/mL; testosterone 82 ng/dL (elevated); fasting insulin elevated with HOMA-IR 4.2. Pelvic US shows bilateral ovaries with 15+ subcapsular follicles (2–9 mm). Which first-line agent is most effective for ovulation induction in this patient, and by what mechanism?
AClomiphene citrate — SERM antagonist at hypothalamus → ↑ FSH
BLetrozole — aromatase inhibitor → ↓ estrogen → ↑ FSH; superior live birth rates vs clomiphene in PCOS
CExogenous LH injections to simulate an LH surge
DProgesterone suppositories to induce ovulation
ECombined OCP — suppresses the HPO axis to "reset" ovulation
B — Letrozole (aromatase inhibitor). This is classic PCOS (obese + oligomenorrhea + hirsutism + LH:FSH > 3 + insulin resistance + string of pearls). Recent RCTs (PPCOS II, Legro et al.) showed letrozole is SUPERIOR to clomiphene for live birth rates in PCOS, making it first-line for ovulation induction. Mechanism: aromatase inhibitor → blocks peripheral + granulosa estrogen synthesis → removes negative feedback → ↑ FSH → follicle recruitment → ovulation. Clomiphene (A) is also effective but second-line in PCOS. Also key: weight loss is first intervention; add metformin for insulin resistance. OCPs (E) suppress ovulation — opposite of what's needed.
Question 12 of 15 — Ectopic Pregnancy
A 24-year-old G1P0 woman presents to the ED with 2 hours of severe right lower quadrant pain and scant vaginal bleeding. Her last menstrual period was 7 weeks ago. She has tachycardia (HR 118), BP 90/60, and diffuse abdominal tenderness with rebound. Urine β-hCG is positive; serum β-hCG is 2,200 mIU/mL but rose only 20% over 48 hours. Transvaginal US shows no intrauterine pregnancy but demonstrates a complex adnexal mass with free fluid in the cul-de-sac. Which anatomic structure has most likely been involved?
AUterine fundus
BEndocervical canal
COvarian cortex
DFallopian tube ampulla
EAbdominal peritoneum
D — Fallopian tube ampulla. Classic ruptured ectopic pregnancy: amenorrhea + unilateral pain + bleeding + hemodynamic instability + β-hCG not doubling + no IUP + complex adnexal mass + free fluid. The ampulla is the most common site (>70%) of ectopic pregnancy — same place where normal fertilization occurs. Risk factors: prior PID, tubal surgery, IUD, endometriosis, smoking. Order of frequency: Ampulla > isthmus > fimbria > ovary > abdomen > cervix. Management: unstable → surgery (salpingectomy/salpingostomy); stable with low β-hCG and no rupture → methotrexate (folate antagonist blocks trophoblast proliferation). Ruptured ectopic → surgical emergency + blood products.
Question 13 of 15 — Invasive Lobular Breast Cancer
A 49-year-old woman has a screening mammogram showing subtle architectural distortion in the left breast. Biopsy reveals tumor cells infiltrating the stroma in a single-file pattern. Immunohistochemistry demonstrates absent E-cadherin, ER positive, PR positive, HER2 negative. MRI reveals a similar-appearing contralateral lesion. Which gene is most likely mutated, and what is the tumor's predicted response to endocrine therapy?
ABRCA1; poor response to tamoxifen (triple-negative)
BTP53; responds well to trastuzumab (HER2-targeted)
DERBB2 (HER2) amplification; responds to trastuzumab
EPTEN; responds to PI3K inhibitors
C — CDH1 (E-cadherin); responsive to endocrine therapy. The single-file ("Indian file") infiltration pattern + loss of E-cadherin + frequent bilaterality are pathognomonic for invasive lobular carcinoma. E-cadherin (encoded by CDH1 gene) normally maintains epithelial cell-cell adhesion — loss allows single-cell dispersion. Hereditary CDH1 mutations cause hereditary diffuse gastric cancer + lobular breast cancer syndrome. Since this tumor is ER+/PR+, it responds well to endocrine therapy: tamoxifen (SERM) premenopausal or aromatase inhibitors (anastrozole, letrozole) postmenopausal. HER2-negative → trastuzumab not indicated (D wrong). Contrast: invasive ductal carcinoma forms stellate/spiculated mass with retraction — not single-file.
Question 14 of 15 — Ovarian CA + Psammoma Bodies
A 58-year-old woman with a BRCA1 mutation (diagnosed after her sister's ovarian cancer) opts for prophylactic bilateral salpingo-oophorectomy at age 55. Pathology reveals a 1.8-cm tumor in the right ovary; histologic sections show papillary projections with concentric laminated calcifications within the tumor cells. Which of the following ovarian tumor types is most likely, and from what cell layer does it arise?
AGranulosa cell tumor from follicular cells — produces estrogen
BDysgerminoma from primordial germ cells — ↑ LDH
CSerous cystadenocarcinoma from germinal (surface) epithelium
DMature teratoma (dermoid cyst) from totipotent germ cells
EKrukenberg tumor from gastric metastasis — signet ring cells
C — Serous cystadenocarcinoma from germinal (surface) epithelium.Psammoma bodies (concentric laminated calcifications) are highly associated with: PSaMMoma mnemonic — Papillary thyroid CA, Serous ovarian cystadenoCA, Meningioma, Mesothelioma. Most ovarian cancers (65–70%) arise from the germinal (surface) epithelium — and serous cystadenocarcinoma is the most common subtype. BRCA1/BRCA2 mutations increase risk of high-grade serous ovarian CA (and breast CA) because BRCA proteins perform homologous recombination DNA repair. Risk-reducing salpingo-oophorectomy is recommended at 35–40. Other ovarian tumor origins: sex cord-stromal (granulosa — Call-Exner bodies, estrogen-producing), germ cell (dysgerminoma, teratoma), metastasis (Krukenberg, bilateral signet ring).
Question 15 of 15 — Comprehensive Menopause/HRT
A 52-year-old woman presents with 18 months of hot flashes, night sweats, and vaginal dryness causing dyspareunia. Her last menstrual period was 16 months ago. She has no personal or family history of breast/ovarian/endometrial cancer, VTE, CAD, or stroke. Her uterus is intact. She wishes to start HRT for symptom relief. Which of the following represents the MOST APPROPRIATE hormonal regimen AND the physiologic rationale?
AEstrogen alone (oral); progesterone is unnecessary since she's postmenopausal
BCombined estrogen + progestin; progestin protects the intact endometrium from estrogen-driven hyperplasia/cancer
CProgesterone-only regimen; sufficient for vasomotor symptoms
B — Combined estrogen + progestin. This is classic menopause (12+ months amenorrhea + vasomotor symptoms + vaginal atrophy). HRT relieves symptoms and preserves bone/skin/brain in appropriately selected patients. The key rule: if a uterus is present, progestin MUST be added to estrogen. Unopposed estrogen → chronic stimulation of the endometrium → endometrial hyperplasia → type I endometrial adenocarcinoma. Progestin counteracts by preventing uncontrolled proliferation (and induces decidualization → regular withdrawal bleeding on cyclic regimens). Estrogen-only HRT is only appropriate for women who have had a hysterectomy (A wrong — the vignette specifies intact uterus). Progesterone alone (C) doesn't treat hot flashes effectively. Clomiphene (D) can't restart ovulation after ovarian follicles are depleted. WHI data informed risks: HRT CI in breast CA hx, VTE, active liver disease, unexplained vaginal bleeding, CAD/stroke history.
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