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Test your basic knowledge |
USMLE Embryo
Start Test
Study First
Subjects
:
health-sciences
,
usmle
Instructions:
Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can
study here
.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.
This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. What axis does the basal plate form? what neural system does it become?
Neuroectoderm
Ventral ; motor
Thyroid - cricoid - arytenoids - corniculate cuneiform
Day 6; maintains corpus luteum; 1st trimester
2. What components do the mesoderm of the branchial arches give rise to?
Week 3-8
Muscles and arteries
Membrane - all 3 from 1st appartus
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
3. What artery is derived branchial (aortic) arch 6?
Mesoderm
A vitelline fistula - failure of vitelline duct to close
secondary palate
Pulm art (prox) and ductus arteriosus
4. The inner layer of the chorionic villi...
Stapedius and hyoid artery
Ventral shaft of penis (penile urethra); labia minora
can make cells
Increase in oxygen concentration which decreases prostaglandin concentration
5. what muscles are derived from branchial arch 4? CN?
Transposition of great vessels (failure to spiral)- right to left shunt; tetralogy of Fallout (right to left shunt caused by skewed development of septum); persistent TA (partial septum development - also right to left shunt)
2nd; 2nd
Excessive resorption of septum primum or secondum (or both)
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
6. what separates the atria from the ventricles?
6-30
Aortic arch (from left side); right subclavian (on the right)
Endocardial cushions
First branchial pouch
7. What is duodenal atresia usually due to? What trisomy is it most often seen in?
Week 8
Failure to recanalize; 21
Failure of bony spinal canal to fuse; no; lower vertebral levels
Maternally derived; meconium
8. What embryological structure gives rise to the coronary sinus?
Endoderm
Left horn of the sinus venosus
Aminoglycosides
Myelencephalon
9. What arises from the fourth aortic arch?
Aortic arch (from left side); right subclavian (on the right)
Ionizing
Allantois
secondary palate
10. in hypospadias - on which side is the abnormal opening? What causes it?
Vascular accident intra uterine; apple peel atresia
Ventral; failure of urogenital folds to close
8
Ampulla
11. What is the effect of teratogens after week 8?
Deformation
Excessive resorption of septum primum or secondum (or both)
Ventral bud
A vitelline fistula - failure of vitelline duct to close
12. What are markers for neural tube defects in the amniotic cavity? CSF?
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
Increased AFP and acetycholinesterase (not ACh!) in CSF
Right horn of the SV
Endocardial cushions
13. Which branchial apparatus develops into the thymus?
3rd pouch
T neuroectoderm
20-50yrs - Abdominal pain - Postprandial fullness - Nausea - Peptic ulcers - Pancreatitis - Rarely - biliary obstruction
Neural crest cells
14. What causes persistent Truncus Arteriosus? What does it result in?
Lacunae in between the chorionic villi
Before getting pregnant!
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
Cranio - caudal; segmental
15. what bone/cartilage and nerves are derived from branchial arch 1?
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Alkylating agents
Muscles and arteries
3rd pouch
16. What part of the vagina does the mullerian duct form? Where does the rest come from?
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Upper 1/3; urogenital sinus
80%
Neural crest cells
17. What congenital abnormality forms a 'double bubble' on xray?
Annular pancrease
8
Increased AFP and acetycholinesterase (not ACh!) in CSF
Week 4; week 3
18. What teratogens can cause discolored teeth?
Bulbos Cordis; right ventricle entirely
Tetracyclines
Polyhydramnios
Common carotid and internal carotid
19. What gene is produced in the zone of polarizing activity?
Sonic Hedgehog
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
SRY gene on Y chromosomes; sertoli and leydi; MIF and androgens; suppression of paramesonephric ducts and dev. of mesonephric (all respectively)
Fluid filled syrinx causes expansion and degeneration of cord tracts
20. From What do the embryoblast and trophoblast form from? What does the embryoblast split into? the trophoblast?
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
mesodermal
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
Primitive ventricle
21. During what months is the fetus most susceptible to teratogens? What trimester?
During; instrinsic
DiGeorge
Embryonic period; 1st trimester
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
22. Which branchial derivative creates the epithelial lining of the palatine tonsils?
Primitive ventricle
5th
2nd pouch
1st cleft/groove (Ectoderm)
23. Cleft palate is a failure of fusion of the lateral palatine processes - the nasal septum and or the ________?
Increased AFP and acetycholinesterase (not ACh!) in CSF
Mesoderm
Lithium
Medial palatine processes
24. What are the two walls of the prosencephalon and What do they become?
Muscular ventricular septum; no
Midgut; 10th week
VSD
Cerebral hemisphere - thalami
25. what other facial defect other than cyclopia is associated with holoprosencephaly?
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
Mid gut to yolk sac; omphalomesenteric duct; 7th week
DHT; estrogen
Cleft lip/palate
26. What do the 2nd through 4th clefts of the branchial apparatus correlate to?
Temporary cervical sinus
Ventral ; motor
can make cells
1st branchial arch
27. Where does fertilization occur?
Amniotic epithelium
3
Nutrient and gas exchange
Ampulla
28. From what aortic arch does the stapedial artery arise? the hyoid?
Where the epiblast and hypoblast fuse
Embryonic period; 1st trimester
can make cells
2nd; 2nd
29. Which branchial derivative accounts for the posterior 2/3 of the tongue?
Metencephalon; cerebellum
3rd and 4th arches
Week 8
Arnold Chiari and Dandy Walker; Arnold Chiari; Dandy Walker; Arnold Chiari
30. what chemo drugs can cause neural tube defects in the fetus?
secondary palate
Hepatic circulation; ligamentum venosum
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
Folate antagonists
31. From What embryonic layer do CNS neurons arise?
8
Surface ectoderm
...
Neuroectoderm
32. What is the mcc of renovascular hypertension in children? What does this predispose to?
Cranio - caudal; segmental
Truncus arteriosus; pulmonary trunk
Week 4; week 3
Renal artery stenosis;
33. What is the notochord? What does the notochord later become?
Mesoderm; nucleous pulposos
Arnold Chiari and Dandy Walker; Arnold Chiari; Dandy Walker; Arnold Chiari
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
Neural crest cells
34. What is DiGeorge syndrome and What does it result in?
Mesoderm; nucleous pulposos
Week 3; primitive streak formation from the epiblast makes the three layers
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
Temporary cervical sinus
35. From where does the pulmonary arteries and the ductus arteriosus arise?
Muscles and arteries
6th aortic arch
After; extrinsic
Neural crest cells
36. What effect does warfarin have on the fetus?
4th arch; 6th arch
Hemorrhage - bone deformities
Mesoderm
Fetal alcohol syndrome; mental retardation
37. From what region does the cerebral hemisphere form?
Ventral ; motor
StyloPharyngeus
Telencephalon
Muscles of Mastication: Temporalis - masseter - Lateral and Medila pterygoids - Mylohyoid - anterior belly of the digastric - tensor tympani - tensor veli palatini; ant 2/3 of tongue
38. From What embryonic layer does the parathyroid arise ?
Endoderm
Sperm plus egg
A vitelline fistula - failure of vitelline duct to close
Skewed development of AP septum
39. From What embryonic layer is the kidney and the adrenal cortex from?
Mesoderm
elevated AFP
Neuroectoderm
Neuroectoderm
40. From what branchial derivative do the parafollicular cells arise?
primary palate
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
4th/5th branchial pouches
Respiratory distress syndrome
41. Where is the most common ectopic thyroid tissue?
Tongue
No organ in each; agenesis no primordial tissue
Valproate acid
Day 6; maintains corpus luteum; 1st trimester
42. What type of - amnios does bilateral agenesis form? What three symptoms does this cause?
Ampulla
Upper 1/3; urogenital sinus
Oligohydramnios
hypertrophy
43. What embryologic structure provides the aorticpulmonary septum?
Fluid filled cavity in spinal cord; C8- T1; arnold chiari II
...
Neural crest migration - they then cause spiral
Folate antagonists
44. What are the two components of the fetal component of the placenta?
Maxillary
Cytotrophoblast and synctiotrophoblast
Rhombencephalon
Sperm plus egg
45. From What embryonic layer is the spleen from?
Scrotum; labia majora
VACTERL- vertebral defect - anal atresia - cardiac defects - tracheo - esophageal fistula - renal defects - limb defects
Mesoderm
Neuroectoderm
46. The spleen is ____________ in origin and supplied by a foregut artery
VACTERL; OCPs and maternal diabetes
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
mesodermal
Prenatal and perinatal
47. From What embryonic layer does the spinal cord arise?
...
4th pouch
Neuroectoderm
Ebsteins anomaly; tricuspid atresia
48. From What embryonic layer are the schwann cells from ?
Wolffian; mullerian
Neural crest cells
VSD
Vascular accident intra uterine; apple peel atresia
49. What is jejunal - ileal - colonic atresia usually due to? What do you see on x ray?
not covered
Absent cerebellar vermis; cystic enlargement of 4th ventricle
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
Vascular accident intra uterine; apple peel atresia
50. What is the leading cause of birth defects in the US? what else is this perpetrator the leading cause of?
Fetal alcohol syndrome; mental retardation
Week 8
Week 4
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)