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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 is the kidney that functions at the interim kidney in the 1st trimester? What does it later contribute to?
3 -4 -6
1st cleft/groove (Ectoderm)
Mesonephros; male genital system
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
2. What causes a patent foramen ovale?
Base of limbs in the zone of polarizing activity; ant - post
1st cleft/groove (Ectoderm)
Decidual basalis
Excessive resorption of septum primum or secondum (or both)
3. What causes meconium discharge from the umbilicus?
Primitive atrium
A vitelline fistula - failure of vitelline duct to close
Stapedius and hyoid artery
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
4. What is a syrinx? Where is it found in syringomelia? What is it associated with?
Neuroectoderm
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Fluid filled cavity in spinal cord; C8- T1; arnold chiari II
Right common cardinal vein and right anterior cardinal vein
5. From where did a branchial cleft cyst arise if it found?
Found in lateral neck; from no obliteration of 2-4th clefts
Neuroectoderm
Endoderm
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
6. From What embryonic layer does the skin dermis arise?
Fluid filled syrinx causes expansion and degeneration of cord tracts
VACTERL; OCPs and maternal diabetes
Pulm art (prox) and ductus arteriosus
Mesoderm
7. Monochorionic - ___________ twins are conjoined
All 3
Endoderm
pyloric stenosis
monoamniotic
8. Where is Wnt 7 gene produced?
blood entering the RA
Apical ectodermal ridge
Mesoderm
Ventral bud
9. From What embryonic layer are the dorsal root and celiac ganglion from?
Urachus/median umbilical ligament; bladder and yolk sac
Prosencephalon - mesencephalon - rhombencephalon
Neural crest cells
Cranio - caudal; segmental
10. What are markers for neural tube defects in the amniotic cavity? CSF?
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
Increased AFP and acetycholinesterase (not ACh!) in CSF
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
Surface ectoderm
11. What do the arches of the branchial apparatus correlate to?
Hepatic circulation; ligamentum venosum
Mesdoerm
They are the edge of neural plate folding; all over the body
Oligohydramnios
12. When does the neural tube form and From what does it form?
Absent cerebellar vermis; cystic enlargement of 4th ventricle
elevated AFP
Neural plate; closes by week 4
DiGeorge
13. What is the female remnant of the gubernaculum? male remnant?
Where the epiblast and hypoblast fuse
Occiptal
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
Neural crest migration - they then cause spiral
14. What connects the thyroid to the tongue? when happens if it doesnt obliterate?
Germinal matrix hemorrhage
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
3rd pouch
15. What is omphalocele? In What trisomies is it seen?
ACE inhibitors - HCTZ
Failure of the urachus to obliterate
Nicotine; preterm labor
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
16. what junction is the last to canalize? what implications does this have down the line?
Myelencephalon
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
Obliterated
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
17. What is the difference between agenesis and aplasia?
No organ in each; agenesis no primordial tissue
Right horn of the SV
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
Mesoderm
18. Name two endocardial cushion defects.
Bones - cartilage - and nerves
Failure to recanalize; 21
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
Ebsteins anomaly; tricuspid atresia
19. From What embryonic layer are the schwann cells from ?
Day 6; maintains corpus luteum; 1st trimester
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
Ectoderm
Neural crest cells
20. Where is erythropoeisis in the weeks 3-8 of fetal development? Where does it occur after that? until when?
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
During; instrinsic
Decreases
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
21. ______________ is associated with ventral curvature of the penis
Failure of the urachus to obliterate; outpouching of the bladder
hypospadias
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
Lots - cleft palate/lip
22. From What embryonic layer does the epithelial linings of the oral cavity arise?
Bones - cartilage - and nerves
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
Surface ectoderm
Week 3; primitive streak formation from the epiblast makes the three layers
23. How do you differentiate a thyroglossal duct cyst from a persistent cervical sinus?
Outgrowth of mesonephric as ureteric bud; most caudal
Week 8
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
Nutrient and gas for exchange; endometrium
24. What does DHT turn the genital tubercle into? estrogen?
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
1st cleft/groove (Ectoderm)
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
Female; paramesonephric; mesonephric
25. What teratogens can cause flipper limbs (limb defects)? What is this drug used for?
IMA
Endocardial cushions
Thalidomide; nausea
Duodenum to transverse colon; distal transverse colon to rectum
26. In anencephaly you see...
1st cleft/groove (Ectoderm)
elevated AFP
Neuroectoderm
Fetal alcohol syndrome; mental retardation
27. What do membranous interventricular septal defect cause? What does this lead to?
primary palate
Initial left to right shunting - then switches
Obliterated; forms tunica vaginalis
Failure to recanalize; 21
28. What causes tetralogy of Fallot?
Week 3-8
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
Skewed development of AP septum
Myelencephalon
29. what closes the ductus arteriousus?
Increase in oxygen concentration which decreases prostaglandin concentration
Failure of the urachus to obliterate
Umbilical - midgut herniates through umbilical ring; SMA
Aortic arch and prox part of subclavian
30. What is annular pancreas associated with in infants?
Foregut; dorsal mesentery (mesodermal)
Initial left to right shunting - then switches
Pataus; fetal alcohol syndrome
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
31. what other facial defect other than cyclopia is associated with holoprosencephaly?
Truncus arteriosus; pulmonary trunk
Cleft lip/palate
Tongue
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
32. From What embryonic layer does the gut tube epithelium arise?
Myelencephalon
Endoderm
StyloPharyngeus
Pharynx to duodenum; duodenum to transverse colon; distal transverse colon to rectum
33. What trisomy is associated with holoprosencephaly? What teratogen?
Nicotine; preterm labor
Prevent recurrent UTIs
Failure of bony spinal canal to fuse; no; lower vertebral levels
Pataus; fetal alcohol syndrome
34. From what aortic arch does the first part of the maxillary artery arise?
Branchial arch 2
1st
No more umbilical circulation emptying into RA
Prenatal and perinatal
35. What do the 2nd through 4th clefts of the branchial apparatus correlate to?
Fetal alcohol syndrome; mental retardation
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Temporary cervical sinus
Week 3-8
36. When is most important to take folic acid to prevent neural tube defects?
Pronephros - mesonephros - metanephros; pronephros; most cranially
4th pouch
Before getting pregnant!
Foregut; dorsal mesentery (mesodermal)
37. From where does the permanent kidney for? is it most caudal or most cranial?
Outgrowth of mesonephric as ureteric bud; most caudal
4th pouch
Endoderm
Fluid filled syrinx causes expansion and degeneration of cord tracts
38. What embryological structures give rise to the SVC?
Prosencephalon
Mesonephros; male genital system
2nd; 2nd
Right common cardinal vein and right anterior cardinal vein
39. what muscles are derived from branchial arch 2?
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
Neural crest cells
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
Mid gut to yolk sac; omphalomesenteric duct; 7th week
40. What causes a vesicourachal diverticulum? What is it?
Thyroid - cricoid - arytenoids - corniculate cuneiform
Failure of the urachus to obliterate; outpouching of the bladder
Neural crest cells
80%
41. From What embryonic layer is the bladder and urethra from?
Neural crest cells
Mesoderm
Female; paramesonephric; mesonephric
Ectoderm; endoderm
42. What is the allantois become? What is this duct connected to ( on both ends)?
Urachus/median umbilical ligament; bladder and yolk sac
Hemorrhage - bone deformities
Maternally derived; meconium
3rd; proximal part of the internal carotid artery
43. Cleft lip is a failure of fusion of ________ and ______.
Maxillary and medial nasal processes
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
primary palate
Arches 3 and 4
44. What are the neural crest cells and where do they come form? where do they go?
They are the edge of neural plate folding; all over the body
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Endoderm
3 -4 -6
45. When does the notochord form? and When does the neural plate form?
lumbosacral
secondary palate
Left horn of the sinus venosus
Mesoderm; 3 week
46. what muscles are derived from branchial arch 1?
Umbilical - midgut herniates through umbilical ring; SMA
Pronephros - mesonephros - metanephros; pronephros; most cranially
T neuroectoderm
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
47. From where does the medulla form?
Nutrient and gas exchange
Alkylating agents
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
Myelencephalon
48. What results in annular pancreas? How does it happen?
Foregut; dorsal mesentery (mesodermal)
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3
Mesoderm; 3 week
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
49. What does the ductus arteriosus shunt blood away from - to where? What is its remnant?
Right horn of the SV
Surface ectoderm
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
No organ in each; agenesis no primordial tissue
50. From What embryonic layer does the pineal gland arise?
Maternally derived; meconium
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
Thalidomide; nausea
Neuroectoderm