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FCPS Part 1 Embryology MCQs
Embryology questions test gametogenesis and early development, germ layers, the development of the heart, gut, pharyngeal arches, face and genitourinary tract, and the congenital anomalies that follow.
Below are 5 free single-best-answer questions drawn from the most frequently examined embryology concepts, each with the answer and a rationale for every option. The full bank has 60 embryology concepts, each asked several different ways.
Free embryology questions
Question 1
Hepatocytes of the liver arise from which germ layer?
- A. Intermediate mesoderm
- B. Endoderm
- C. Mesoderm
- D. Ectoderm
- E. Neural crest
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Answer: B. Endoderm
The liver, gallbladder and pancreas bud from foregut endoderm. The rectum above the pectinate line is hindgut endoderm, while the anal canal below it comes from proctodeal ectoderm.
Why not the others: Ectoderm: skin, nervous system and the lower anal canal. Mesoderm: muscle, connective tissue and Kupffer cells' stroma. Neural crest: melanocytes and adrenal medulla. Intermediate mesoderm: kidneys and gonads.
High-yield: Gut tube epithelium and its glands = endoderm; anal canal below pectinate line = ectoderm.
Question 2
Main site of fetal erythropoiesis in the second trimester:
- A. Brain
- B. Yolk sac
- C. Kidney
- D. Liver
- E. Bone marrow
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Answer: D. Liver
The liver replaces the yolk sac as the main haemopoietic organ from about six weeks and dominates mid-gestation. Its portal vein and hepatic artery supply makes infarction uncommon.
Why not the others: Yolk sac: first erythropoiesis, weeks 3 to 8. Bone marrow: takes over late in gestation. Kidney: end-arterial supply, infarcts readily. Brain: highly ischaemia-sensitive.
High-yield: Liver: fetal erythropoiesis in mid-gestation and dual blood supply.
Question 3
Beta-hCG detected in maternal serum in early pregnancy is secreted by:
- A. Yolk sac
- B. Fibroblasts
- C. Syncytiotrophoblast
- D. Decidua
- E. Corpus luteum
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Answer: C. Syncytiotrophoblast
The syncytiotrophoblast is the multinucleate outer layer of the villus that secretes hCG, hPL and steroid hormones. The cytotrophoblast beneath is the germinative layer.
Why not the others: Corpus luteum: target of hCG, not the source. Decidua: maternal tissue. Endometrium: maternal. Yolk sac: early haematopoiesis. Fibroblasts: stroma.
High-yield: hCG from syncytiotrophoblast; corpus luteum only responds to it.
Question 4
Phenotypic female with primary amenorrhoea, normal breasts, scanty pubic hair, blind vagina and no uterus:
- A. Androgen insensitivity syndrome
- B. Mullerian agenesis (MRKH syndrome)
- C. Turner syndrome
- D. Congenital adrenal hyperplasia
- E. Klinefelter syndrome
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Answer: A. Androgen insensitivity syndrome
A defective androgen receptor leaves testosterone ineffective, so external genitalia are female and pubic and axillary hair are scanty. Testes produce Mullerian inhibiting factor, so the uterus is absent, and aromatised testosterone allows breast development.
Why not the others: Turner: 45,X, streak gonads, no breasts. MRKH: normal pubic hair, 46,XX. Klinefelter: male. CAH: virilisation of a 46,XX infant. Kallmann: anosmia with absent puberty.
High-yield: Absent pubic hair is the discriminator from MRKH.
Question 5
Respiratory bronchioles appear and capillaries grow in around them during which phase of lung maturation?
- A. Saccular stage
- B. Pseudoglandular stage
- C. Alveolar stage
- D. Canalicular stage
- E. Embryonic stage
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Answer: D. Canalicular stage
In the canalicular period, terminal bronchioles give rise to respiratory bronchioles and primitive alveolar ducts, and a rich capillary network invades. This creates the first possible air–blood interface.
Why not the others: Embryonic stage: lung bud and main bronchi. Pseudoglandular stage: conducting airways, no respiration possible. Saccular stage: terminal sacs and surfactant. Alveolar stage: mature alveoli from late fetal life.
High-yield: Canalicular = canals plus capillaries, weeks 16–25.
Keep going with embryology
Anaesgen brings every concept back on a spaced-repetition schedule timed to your exam date, as a different question each time, with full mock papers for Paper 1 and 2.
Get full access Try the 5 sample questionsHigh-yield embryology one-liners
The most-tested embryology concepts, as a clue and the answer it points to:
- Hepatocytes, islets, upper rectum, gut lining → endoderm.
- Mid-trimester erythropoiesis, dual blood supply, resists infarction → liver.
- hCG, hPL, hormone-making outer villus layer → syncytiotrophoblast.
- Primary amenorrhoea, breasts, no pubic hair, no uterus, 46,XY → androgen insensitivity.
- Weeks 16–25, respiratory bronchioles, vascularisation → canalicular.
- Serous membranes, limb bud, somatic/splanchnic split → lateral plate mesoderm.
- Uterus, tubes, upper vagina, bicornuate uterus → paramesonephric ducts.
- Covered sac, umbilical ring, midgut failed to return, chromosomal anomalies → omphalocele.
- Full patency of allantois, urine at umbilicus → urachal fistula.
- Preterm, bounding pulses, wide pulse pressure, indomethacin closes → PDA.
- Polyhydramnios, double bubble, trisomy 21 → duodenal atresia.
- Commonest VSD, aorticopulmonary septum, neural crest → membranous VSD.
- Third arch, only muscle of CN IX, from styloid process → stylopharyngeus.
- Midline, below hyoid, moves with tongue protrusion → thyroglossal duct cyst.
- Hypospadias, ventral meatus, chordee → urogenital folds.
- Down syndrome, AV septal defect, common AV canal → endocardial cushions.
- Epimere, epaxial myotome, deep back muscles → longissimus (erector spinae).
- Placental return, about 80% saturation, single vessel → umbilical vein.
- Proximal pulmonary arteries, ductus arteriosus → 6th aortic arch.
- Yolk sac to bladder, remnant urachus → allantois.
Other FCPS Part 1 subjects
AnatomyPharmacologyPathologyBiochemistry & GeneticsCardiovascularNeurophysiologyMicrobiologyHaematologyGeneral PhysiologyImmunologyEndocrineRespiratoryObstetrics & GynaeRenal & Acid-BaseHistologyGI & LiverPhysicsBiostatistics
New to the exam? Read the FCPS Part 1 exam guide: dates, format and a 12-week study plan.