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❤️ Physiology · Part 9 revision hub
Reproductive Physiology
Everything you need to revise this Part in one place — the one‑page note for every concept, a rapid‑revision sheet, exam‑style questions that point you back to the right concept, flashcards, staged cases and viva practice.
8 concepts20 MCQs20 flashcards5 cases15 viva questions
📝 The plate wall
Every concept in this Part as a one‑page handwritten note. Open one to read it in full and zoom.
Concept 95
Becoming Male or Female, and Puberty
Concept 96
The Testis: sperm and testosterone factory
Concept 97
Testosterone, Semen and Male Fertility
Concept 98
The Ovary: eggs and hormones
Concept 99
The Menstrual Cycle
Concept 100
Pregnancy and Birth
Concept 101
Breastfeeding
Concept 102
Contraception and Menopause
⚡ Rapid revision
The whole Part on one screen — read it the night before.
Development and the male axis
- Layers: chromosomes → gonad (SRY → SOX9 → testis) → ducts (AMH removes Müllerian; testosterone keeps Wolffian) → external (DHT via 5α‑reductase 2).
- CAIS: 46,XY, testes, no uterus, female external; 5α‑RD2: ambiguous at birth, virilises at puberty; PMDS: male with uterus.
- Puberty: KNDy/kisspeptin reactivate GnRH pulses; leptin permissive; adrenarche separate. First sign: thelarche (girls), testes ≥ 4 mL (boys).
- Precocious < 8 (girls) / < 9 (boys); delayed: no breasts by 13 / no testicular growth by 14.
- LH → Leydig → testosterone; FSH → Sertoli → ABP, inhibin B, support. Inhibin B selectively suppresses FSH.
- Blood–testis barrier = Sertoli tight junctions. Intratesticular T ≫ serum T.
- Spermatogenesis ~74 days; primary spermatocyte 2n 4C → secondary 1n 2C → spermatid 1n 1C.
- Exogenous testosterone → ↓ LH/FSH → ↓ intratesticular T → azoospermia.
Androgens, semen and the ovary
- T → DHT (prostate, genitalia, hair) and → E2 (epiphyseal fusion, bone, feedback).
- Semen: seminal vesicles ~60–70% (fructose), prostate ~20–30% (PSA, citrate, zinc).
- WHO 2021 5th centiles: 1.4 mL, 16 M/mL, 39 M total, 42% total motility, 30% progressive, 4% normal forms.
- Erection: NO → cGMP (parasympathetic); emission sympathetic; expulsion pudendal. PDE5 inhibitors + nitrates contraindicated.
- Theca (LH, CYP17A1) → androgens; granulosa (FSH, aromatase) → oestradiol.
- Oocyte arrest: prophase I (fetal) → metaphase II (ovulation) → completes at fertilisation.
- AMH = follicle quantity, not quality. PCOS: Rotterdam 2 of 3 after excluding mimics.
Cycle, pregnancy, lactation, menopause
- Sustained E2 (~200 pg/mL, ~36–50 h) → positive feedback → LH surge → ovulation ~34–36 h after onset.
- Follicular phase varies; luteal ~14 ± 2 days. Mid‑luteal P4 ~7 days before menses confirms ovulation.
- E2: proliferative endometrium, spinnbarkeit; P4: secretory endometrium, thick mucus, BBT ↑ 0.3–0.5 °C.
- hCG rescues corpus luteum; luteo‑placental shift ~7–9 weeks; hCG peaks 8–10 weeks.
- Pregnancy: plasma volume ↑ 40–50%, CO ↑ 30–50%, SVR ↓, PaCO₂ ~30 mmHg, GFR ↑ ~50%, hypercoagulable, insulin resistant (hPL).
- Labour: functional progesterone withdrawal, oxytocin receptors, gap junctions, PGs; Ferguson reflex.
- Lactation: P4 fall triggers secretory activation; prolactin synthesis (JAK2–STAT5); oxytocin ejection (myoepithelium).
- LAM needs all three: amenorrhoea, full breastfeeding (≤ 4 h day / 6 h night), < 6 months.
- Menopause: 12 months amenorrhoea; FSH ↑↑; oestrone dominant; KNDy‑driven hot flushes; bone loss.
🎯 Single‑best‑answer MCQs
Pick an answer to see the explanation — and the concept to revisit if you missed it. Your answers are saved on this device.
Score 0 / 00 of 20 answered
Question 1
The hormone responsible for regression of the Müllerian ducts is:
Question 2
A 46,XY infant with ambiguous genitalia who virilises at puberty and has a raised testosterone:DHT ratio most likely has:
Question 3
The first physical sign of puberty in most boys is:
Question 4
The blood–testis barrier is formed by:
Question 5
A man with infertility has high FSH, normal LH and normal testosterone. The most likely defect lies in:
Question 6
A secondary spermatocyte is best described as:
Question 7
Epiphyseal closure in males is mediated mainly by:
Question 8
Azoospermia with low semen volume, acidic pH and absent fructose suggests:
Question 9
Sildenafil enhances erection by:
Question 10
Granulosa cells convert androgens to oestradiol using:
Question 11
At ovulation, the oocyte is arrested at:
Question 12
Serum AMH is best used to estimate:
Question 13
The LH surge is triggered by:
Question 14
In a woman with regular 35‑day cycles, ovulation is best confirmed by serum progesterone on about:
Question 15
Variation in menstrual cycle length is mainly due to variation in the:
Question 16
The corpus luteum is maintained in early pregnancy by:
Question 17
Which change is physiological in the third trimester?
Question 18
Copious milk secretion after delivery is triggered mainly by:
Question 19
The milk‑ejection reflex results from oxytocin acting on:
Question 20
After menopause, FSH rises because of loss of:
🃏 Flashcards
Say the answer out loud before you flip. Shuffle once you know the order.
Card 1 of 20
🩺 Staged clinical cases
Read the presentation, decide what is going on and what you would do — then reveal the reasoning.
Case 1 — Primary amenorrhoea in a tall teenager
Stage A: A 16‑year‑old girl has never menstruated. Breast development is normal, but pubic and axillary hair are sparse. Examination shows a short, blind‑ending vagina and bilateral inguinal swellings.
Case 2 — A bodybuilder who cannot conceive
Stage A: A 29‑year‑old man has 18 months of infertility. He has used injectable testosterone and other anabolic steroids for 2 years. His testes are small and soft.
Case 3 — Irregular periods, acne and weight gain
Stage A: A 24‑year‑old woman has 4–6 periods a year, acne and hirsutism. BMI 31 kg/m²; acanthosis nigricans on the neck.
Linked concepts: 98. The Ovary: eggs and hormones, 99. The Menstrual Cycle
Case 4 — Breathless at 34 weeks with a "normal" gas
Stage A: A 30‑year‑old at 34 weeks with asthma has worsening wheeze for 2 days. Respiratory rate 28/min, SpO₂ 94% on air.
Linked concepts: 100. Pregnancy and Birth
Case 5 — No milk after a massive bleed
Stage A: A 27‑year‑old needed 8 units of blood for postpartum haemorrhage. Six days later her breasts have not become full and she cannot breastfeed. She is tired and dizzy on standing.
Linked concepts: 101. Breastfeeding, 85. Concept 85
🎤 Viva practice
Answer aloud as if an examiner asked you — then check the model points.
Viva 1
Outline the layers of sexual differentiation.
Viva 2
Why does a woman with CAIS have breasts but no uterus?
Viva 3
What initiates puberty?
Viva 4
Describe the functions of Sertoli cells.
Viva 5
Why does exogenous testosterone cause infertility?
Viva 6
Name the actions of DHT.
Viva 7
Interpret azoospermia with normal FSH and normal testes.
Viva 8
Explain the two‑cell two‑gonadotropin model.
Viva 9
How is a dominant follicle selected?
Viva 10
Explain positive feedback in the cycle.
Viva 11
How do you confirm ovulation?
Viva 12
Why is PaCO₂ low in pregnancy?
Viva 13
What causes the onset of human labour?
Viva 14
Distinguish the roles of prolactin and oxytocin in lactation.
Viva 15
How does the combined pill prevent pregnancy?
Keep going
Educational only — not a substitute for clinical judgement, supervision, or local guidelines.