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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. From What embryonic layer does the sensory organs of the ear arise?
Surface ectoderm
Diencephalon
Cranio - caudal; segmental
2nd; 2nd
2. What does DHT turn the labioscrotal swelling into? estrogen?
Valproate acid
Endoderm
Respiratory distress syndrome
Scrotum; labia majora
3. What type of blood do umbilical arteries carry? From where to where?
Tongue
DiGeorge
Deoxygenated blood; fetal internal iliac arteries to placenta
Mullerian inhibitory factor from Sertoli cells; increased androgen from Leydig cells
4. What is the effect of teratogens after week 8?
Right horn of the SV
Fetal and maternal
Deformation
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
5. what drug is used to help close a PDA? what else does this drug treat?
Indomethacin; blocks PG production
Germinal matrix hemorrhage
Allantois
Failure of the urachus to obliterate; outpouching of the bladder
6. From What embryonic layer do the astrocytes arise?
Mesencephalon
Dorsal; sensory
During; instrinsic
Neuroectoderm
7. Which part of the chorionic villi can make cells?
Cytotrophoblast
Oligohydramnios
Tunica vaginalis not fully fused
secondary palate
8. From What embryonic layer does the parathyroid arise ?
Endoderm
Deoxygenated blood; fetal internal iliac arteries to placenta
Mid gut to yolk sac; omphalomesenteric duct; 7th week
Amniotic cavity and yolk sac
9. What is the defect in spina bifida occulta? is there any structural herniation? where on the spinal cord is it usually seen?
Day 6; with implantation
Hypertrophy of muscularis externis of pylorus; surgical incision
Failure of bony spinal canal to fuse; no; lower vertebral levels
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
10. what closes the ductus arteriousus?
Thalidomide; nausea
Neuroectoderm
6th aortic arch
Increase in oxygen concentration which decreases prostaglandin concentration
11. Which branchial derivative accounts for the sensation and taste in the posterior 2/3 of the tongue? how about the very back?
80%
Week 3; primitive streak formation from the epiblast makes the three layers
Amniotic epithelium
4th arch; 6th arch
12. What artery is derived branchial (aortic) arch 1?
Found in lateral neck; from no obliteration of 2-4th clefts
Decreased separation of hemispheres across midline; cyclopia
Pharynx to duodenum; duodenum to transverse colon; distal transverse colon to rectum
Maxillary
13. What does DHT turn the urogenital folds into? estrogen?
Oxygenated; placenta to fetus (IVC)
All or none
Ventral shaft of penis (penile urethra); labia minora
is no longer intact
14. From what aortic arch does the first part of the maxillary artery arise?
Ectoderm
Endoderm
Neural crest cells
1st
15. When does the blastocyst split into two disks? What is this disk called? What are the two germ layers called?
Endoderm - floor of primitive pharynx
Week 2; bilaminar disk; epiblast and hypoblast
Tunica vaginalis not fully fused
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
16. What do the arches of the branchial apparatus correlate to?
Prosencephalon - mesencephalon - rhombencephalon
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
Mesdoerm
Cleft lip/palate
17. what results if they dont? What can increase the risks of this?
Persistent connection between amniotic cavity and spinal canal; low folic acid
Congenital and chromosomal abnormalities
Mesoderm
1st branchial arch
18. What causes the increase in left atrial pressure to close the fossa ovale?
XII
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
Neural crest cells
Decreased pulmonary resistance in the pulmonary vasculature
19. What is an arnold chiari II malformation? through what hole does it herniate?
3rd; proximal part of the internal carotid artery
Cerebellar tonsillar herniation through foramen magnum
During; instrinsic
...
20. Which branchial derivative creates the epithelial lining of the palatine tonsils?
2nd pouch
Neuroectoderm
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
Prostaglandins
21. From What embryonic layer are the dorsal root and celiac ganglion from?
Nicotine; preterm labor
Dorsal ventral axis
Neural crest cells
Deoxygenated blood; fetal internal iliac arteries to placenta
22. What causes a vesicourachal diverticulum? What is it?
Failure of the urachus to obliterate; outpouching of the bladder
They are the edge of neural plate folding; all over the body
Mesonephros; male genital system
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
23. Where does the blastocyst implant in the uterus? During what phase of the menstrual cycle?
Post. sup wall; luteal phase
Cerebellar tonsillar herniation through foramen magnum
Primitive atrium
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
24. What do the 2nd through 4th clefts of the branchial apparatus correlate to?
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
Temporary cervical sinus
Week 3-8
Incomplete fusion of paramesonephric ducts; UT abnormalities and infertility
25. What does DHT turn the urogenital sinus into? estrogen?
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
Fetal and maternal
Mid gut to yolk sac; omphalomesenteric duct; 7th week
26. Pyloric stenosis is characterized by _____________ of muscularis externis in the sphincter
hypertrophy
Pataus; fetal alcohol syndrome
LH
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
27. From What embryonic layer does the adenohypophysis arise?
not covered
...
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
Surface ectoderm
28. How many umbilical arteries are there? How many umbilical veins?
Neuroectoderm
2; 1
2nd; 2nd
Surface ectoderm
29. What two things cause VACTERL syndrome?
Week 8
4th week
OCPS and maternal diabetes
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
30. From where did a branchial cleft cyst arise if it found?
Mesoderm
Found in lateral neck; from no obliteration of 2-4th clefts
arnold chiari associated with thoraclumbar myelomeningocele
Foregut; dorsal mesentery (mesodermal)
31. What does the first branchial pouch create?
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Right common cardinal vein and right anterior cardinal vein
Mesencephalon
...
32. What does the maternal component of the placenta provide? Where is it derived from?
ACE inhibitors - HCTZ
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
Female; paramesonephric; mesonephric
Nutrient and gas for exchange; endometrium
33. From What embryonic layer does the neurohypophysis arise?
Neuroectoderm
Prostaglandins
Greater horn of hyoid; CN IX (styloPharyngeus)
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
34. By what week is the neural tube supposed to be closed? when did it start forming?
Week 4; week 3
Right horn of the SV
Synctiotrophoblast; outer; no
Endoderm
35. From what arches are the neural crest cells that form the aorticpulmonary septum derived?
3 -4 -6
DHT; estrogen
Decreases
Decidual basalis
36. What part of the fetal comp of the placenta secretes hCG? is this part on the inner or outer layer of the chorionic villi? does it make cells?
Bone/cartilage and nerves
Synctiotrophoblast
Synctiotrophoblast; outer; no
Rhombencephalon
37. What is holoprosencephaly? what eye disorder does it result in?
3rd and 4th arches
Decreased separation of hemispheres across midline; cyclopia
Vascular accident intra uterine; apple peel atresia
Surface ectoderm
38. What weeks are considered the 'embryonic period'?
3rd pouch
Week 3-8
4th arch; 6th arch
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
39. What does the RET gene encode? what neoplasias is it associated with?
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
4th week
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3
Ventral bud
40. 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
Prosencephalon - mesencephalon - rhombencephalon
Hepatic circulation; ligamentum venosum
Nutrient and gas exchange
41. What is annular pancreas associated with in infants?
Common carotid and internal carotid
3rd pouch
Neuroectoderm
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
42. What causes urine discharge from the umbilicus?
External auditory meatus
Failure of the urachus to obliterate
hypertrophy
Spinothalamic first
43. From where does the medulla form?
Myelencephalon
Amniotic cavity and yolk sac
Neural crest cells
Metencephalon; cerebellum
44. What is the allantois become? What is this duct connected to ( on both ends)?
Aminoglycosides
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Urachus/median umbilical ligament; bladder and yolk sac
Thickened ectoderm at end of each developing limb
45. What components do the mesoderm of the branchial arches give rise to?
Muscles and arteries
Surface ectoderm
Endocardial cushions
Tunica vaginalis not fully fused
46. When does hCG secretion take place? with what event?
2nd; 2nd
T neuroectoderm
Day 6; with implantation
A vitelline fistula - failure of vitelline duct to close
47. How is amniontic fluid excreted? How is amniotic fluid resorped?
2nd pouch
Amniotic cavity and yolk sac
Prosencephalon - mesencephalon - rhombencephalon
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
48. What is the most common autopsy finding in brains of premature infants?
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
Germinal matrix hemorrhage
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
Arches 3 and 4
49. what bone/cartilage and nerves are derived from branchial arch 1?
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Cerebellar tonsillar herniation through foramen magnum
XII
Mid gut to yolk sac; omphalomesenteric duct; 7th week
50. _____________is common in 1st born males
pyloric stenosis
Week 3-8
Dorsal ventral axis
Pulm art (prox) and ductus arteriosus