Test your basic knowledge |

USMLE Embryo

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 artery is derived branchial (aortic) arch 6?
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Tetracyclines
Left horn of the sinus venosus
Pulm art (prox) and ductus arteriosus

2. Which branchial apparatus derivative makes the tympanic membrane of the ear?
Week 4
Membrane - all 3 from 1st appartus
Thalidomide; nausea
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18

3. When does the blastocyst split into two disks? What is this disk called? What are the two germ layers called?
Nutrient and gas exchange
Week 2; bilaminar disk; epiblast and hypoblast
septum primum and/or secundum
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast

4. From What embryonic layer are the pia and arachnoid from?
Pronephros - mesonephros - metanephros; pronephros; most cranially
Valproate acid
Neural crest cells
Absent cerebellar vermis; cystic enlargement of 4th ventricle

5. What artery is derived branchial (aortic) arch 4?
Surface ectoderm
Aortic arch and prox part of subclavian
No organ in each; agenesis no primordial tissue
Maxillary

6. what week do the genitalia start to have male/female characteristics? What trimester is that?
mesodermal
Cleft lip/palate
Week 10-12; end of 1st trimester
Prostaglandins

7. what muscles are derived from branchial arch 6? CN?
Endocardial cushions
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
mesodermal
Synctiotrophoblast

8. What artery is derived branchial (aortic) arch 2?
Week 4
Persistent connection between amniotic cavity and spinal canal; low folic acid
Epiblast
Stapedius and hyoid artery

9. From which branchial derivative does the anterior 2/3 of the tongue develop?
XII
1st branchial arch
Week 4
DiGeorge

10. At what week does the fetus look like a baby?
Bone/cartilage and nerves
Epispadias
Midgut; 10th week
Week 8

11. What is meckel's diverticulum? What is it associated with? What does that cause?
Surface ectoderm
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
Grooves/clefts; arches; pouches
Excessive resorption of septum primum or secondum (or both)

12. What is the female remnant of processus vaginalis? male remnant?
Bulbos Cordis; right ventricle entirely
Ventral ; motor
Obliterated; forms tunica vaginalis
Mesdoerm

13. what drug is used to help close a PDA? what else does this drug treat?
Surface ectoderm
Neural crest cells
Mesoderm; 3 week
Indomethacin; blocks PG production

14. What embryological structure gives rise to the trabeculated parts of the left and right ventricle?
Polyhydramnios
Failure of bony spinal canal to fuse; no; lower vertebral levels
Mesoderm
Primitive ventricle

15. What causes urine discharge from the umbilicus?
Failure of the urachus to obliterate
Persistent connection between amniotic cavity and spinal canal; low folic acid
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
Neuroectoderm

16. During what periods do the damages that cerebral palsy causes occur?
Nicotine; preterm labor
Prenatal and perinatal
Stapedius and hyoid artery
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII

17. By what week is there fetal movement?
hypertrophy
Week 8
Neural crest cells
Mental retardation - holoprosencephaly - facial features - fistulas

18. what bone/cartilage and nerves are derived from branchial arch 1?
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Maxillary and medial nasal processes
Rhombencephalon
Neuroectoderm

19. which tracts are damaged first in syringomelia? What tract is preserved?
septum primum and/or secundum
Branchial arch 2
Spinothalamic first
Primitive ventricle

20. From what region do the thalami form?
All 3
Mesoderm
Diencephalon
Gastric outlet obstruction (bilious vomiting - feeding intolerance - abdominal distention)

21. From What embryonic layer do the astrocytes arise?
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
Neuroectoderm
Mesencephalon
Mesoderm

22. What are the aspects of fetal alcohol syndrome?
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
Base of limbs in the zone of polarizing activity; ant - post
Fetal and maternal
Mental retardation - holoprosencephaly - facial features - fistulas

23. Which branchial derivative creates the epithelial lining of the palatine tonsils?
Week 4
2nd pouch
Failure to recanalize; 21
SRY gene on Y chromosomes; sertoli and leydi; MIF and androgens; suppression of paramesonephric ducts and dev. of mesonephric (all respectively)

24. What does the foramen ovale shunt blood from - to where? What is its remnant?
From teh lung;blood from IVC in RA to LA; fossa ovalis
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3
Week 3-8
Neural crest cells

25. What connects the thyroid to the tongue? when happens if it doesnt obliterate?
2; 1
Ionizing
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)
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct

26. which genital embryology is default? From what duct? what duct degenerates without signal to stay?
Female; paramesonephric; mesonephric
Ventral ; motor
Mesdoerm
VACTERL; OCPs and maternal diabetes

27. What is a teratogen that causes Ebsteins anomaly? What is ebsteins anomaly?

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

28. what results if they dont? What can increase the risks of this?
Persistent connection between amniotic cavity and spinal canal; low folic acid
Hemorrhage - bone deformities
Endoderm
Day 6; with implantation

29. is epispadias or hypospadias associated with exstrophy of the bladder?
Neural crest cells
4th pouch
Prosencephalon - mesencephalon - rhombencephalon
Epispadias

30. what bone/cartilage and nerves are derived from branchial arch 3?
Greater horn of hyoid; CN IX (styloPharyngeus)
Pataus; fetal alcohol syndrome
Neural crest cells
mesodermal

31. What gene is produced in the zone of polarizing activity?
Aortic arch and prox part of subclavian
...
Week 4; week 3
Sonic Hedgehog

32. What does the RET gene encode? what neoplasias is it associated with?
Germinal matrix hemorrhage
Wolffian; mullerian
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
Endoderm

33. Monochorionic - ___________ twins are conjoined
3rd; proximal part of the internal carotid artery
VACTERL; OCPs and maternal diabetes
Outgrowth of mesonephric as ureteric bud; most caudal
monoamniotic

34. What is the initial step to interventricular septum development? is it complete?
Muscular ventricular septum; no
During; instrinsic
elevated AFP
Tongue

35. What is duodenal atresia usually due to? What trisomy is it most often seen in?
blood entering the RA
Mesoderm
Failure to recanalize; 21
Failure of the urachus to obliterate

36. What three layers form during gastrulation? From What do they form? and what week does gastrulation occur?
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3
Week 4
Hemorrhage - bone deformities

37. From where did a branchial cleft cyst arise if it found?
6-30
Prostaglandins
Found in lateral neck; from no obliteration of 2-4th clefts
3rd; proximal part of the internal carotid artery

38. When does erythropoeisis begin in the bone marow?
Neural crest cells
28 week onward
Thickened ectoderm at end of each developing limb
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum

39. What is hypoplasia? is primordial tissue present?
Incomplete; yes
Ebsteins anomaly; tricuspid atresia
Gastric outlet obstruction (bilious vomiting - feeding intolerance - abdominal distention)
Fallopian tube - uterus - upper 1/3 of vagina

40. what muscles are derived from branchial arch 1?
Apical ectodermal ridge
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
8
Nutrient and gas for exchange; endometrium

41. What embryological structure gives rise to the coronary sinus?
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
Neural crest cells
Maxillary and medial nasal processes
Left horn of the sinus venosus

42. How is amniontic fluid excreted? How is amniotic fluid resorped?
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
2nd; 2nd
Aortic arch and prox part of subclavian
V3; VII

43. From What embryonic layer does the pineal gland arise?
2nd pouch
Hypertrophy of muscularis externis of pylorus; surgical incision
Neural crest cells
Neuroectoderm

44. Which branchial derivative accounts for the posterior 2/3 of the tongue?
3rd and 4th arches
Thickened ectoderm at end of each developing limb
Hypertrophy of muscularis externis of pylorus; surgical incision
Ovarian ligament and round ligament of uterus; anchors testes within scrotum

45. From What embryonic layer does bone of the skulls arise?
Decreased pulmonary resistance in the pulmonary vasculature
Aortic arch (from left side); right subclavian (on the right)
Neural crest cells
Prenatal and perinatal

46. When does hcG get secreted? What does it do?up until when ?
hypospadias
Day 6; maintains corpus luteum; 1st trimester
Surface ectoderm
elevated AFP

47. From What embryonic layer does the thyroid follicular cells arise?
No organ in each; agenesis no primordial tissue
Endoderm
Synctiotrophoblast
Apical ectodermal ridge

48. From What embryonic layer does the neurohypophysis arise?
Persistent connection between amniotic cavity and spinal canal; low folic acid
Grooves/clefts; arches; pouches
Neuroectoderm
Alkylating agents

49. From What embryonic layer are the dorsal root and celiac ganglion from?
can make cells
Blind upper esophagus with lower esophagus connected to trachea; cyanosis - choking and vomiting with feeding; air bubble on CXR; polyhydramnios; failure to pass NG tube; pneumonitis
Neural crest cells
Amniotic cavity and yolk sac

50. Blood coming in the umbilical vein is ____ saturated
hypertrophy
80%
Endoderm
Pharynx to duodenum; duodenum to transverse colon; distal transverse colon to rectum