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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 aortic arch does the stapedial artery arise? the hyoid?
Stapedius and hyoid artery
2nd; 2nd
DES
hypospadias
2. what bone/cartilage and nerves are derived from branchial arch 2?
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
Pataus; fetal alcohol syndrome
Neural crest migration - they then cause spiral
3. Monochorionic - ___________ twins are conjoined
monoamniotic
OCPS and maternal diabetes
Mid gut to yolk sac; omphalomesenteric duct; 7th week
Tunica vaginalis not fully fused
4. What causes the decrease in Right atrial pressure to close the fossa ovale?
Mesoderm
No more umbilical circulation emptying into RA
Mesoderm
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
5. What are the neural crest cells and where do they come form? where do they go?
Mesoderm
They are the edge of neural plate folding; all over the body
Valproate acid
Pronephros - mesonephros - metanephros; pronephros; most cranially
6. What day is the amnion formed?
mesoderm
8
Occiptal
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
7. What are the two types of posterior fossa malformations? which one results in a hindbrain crowding? and which results in an enlarged posterior fossa? which one is associated with syringomelia?
Surface ectoderm
DiGeorge
septum primum and/or secundum
Arnold Chiari and Dandy Walker; Arnold Chiari; Dandy Walker; Arnold Chiari
8. How many components are there to the placenta? What are they called?
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
mesoderm
Truncus arteriosus; pulmonary trunk
Fetal and maternal
9. To what germ layer does the branchial pouches correlate to?
Female; paramesonephric; mesonephric
Endoderm
Endocardial cushions
Renal artery stenosis;
10. 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
Hypospadias
Mesoderm
11. What day is the chorion formed?
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Arnold chiari; syringomyelia
Cytotrophoblast and synctiotrophoblast
3
12. what muscles are derived from branchial arch 2?
Deoxygenated blood; fetal internal iliac arteries to placenta
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
Neuroectoderm
28 week onward
13. What is omphalocele? In What trisomies is it seen?
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
elevated AFP
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Decreases
14. From where does the ureteric bud arise? What does it give rise to?
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
Mesoderm
First branchial pouch
15. What is perinauds syndrome?
Telencephalon
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
Endocardial cushions
Before getting pregnant!
16. From What embryonic layer does the brain arise?
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
Neuroectoderm
3rd pouch
Absent cerebellar vermis; cystic enlargement of 4th ventricle
17. Blood coming in the umbilical vein is ____ saturated
3rd and 4th arches
Neural plate; closes by week 4
2nd; 2nd
80%
18. From which myotomes are muscles of the tongue derived from?
28 week onward
DiGeorge
Mesoderm
Occiptal
19. From What embryonic layer are the schwann cells from ?
Week 3; primitive streak formation from the epiblast makes the three layers
Turners; inferior
Neural crest cells
Pataus; fetal alcohol syndrome
20. In what chromosomal disorder is horseshoe kidney commonly seen? what poles of the kidneys fuse?
elevated AFP
Yolk sac; 3rd week
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
Turners; inferior
21. what muscles are derived from branchial arch 6? CN?
LH
Neural crest cells
Cerebral hemisphere - thalami
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
22. Where does fertilization occur?
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
Ampulla
Endoderm
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
23. What are the two components of the fetal component of the placenta?
Cytotrophoblast and synctiotrophoblast
They are the edge of neural plate folding; all over the body
monoamniotic
Obliterated
24. What is an example of a syndrome that can cause abnormal neural crest migration and thus CV abnormalities?
Scrotum; labia majora
Post. sup wall; luteal phase
DiGeorge
Fetal alcohol syndrome; mental retardation
25. what week do the genitalia start to have male/female characteristics? What trimester is that?
Neural crest cells
Fetal and maternal
Week 10-12; end of 1st trimester
Endoderm
26. The spinal cord is made from...
T neuroectoderm
Decidual basalis
Neural crest cells
Dorsal; faulty positioning of genital tubercle
27. What is the notochord? What does the notochord later become?
Mesoderm; nucleous pulposos
Ionizing
Neural crest cells
Temporary cervical sinus
28. what other facial defect other than cyclopia is associated with holoprosencephaly?
Neural crest cells
Cleft lip/palate
Lithium
Renal artery stenosis;
29. What are two common findings in pyloric stenosis?
Increase in oxygen concentration which decreases prostaglandin concentration
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Decreases
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
30. What is germinal matrix hemorrhage associated with?
Endoderm
Wolffian; mullerian
Surface ectoderm
Respiratory distress syndrome
31. From What embryonic layer are the melanocytes from?
Neuroectoderm
Stapedius and hyoid artery
Aminoglycosides
Neural crest cells
32. The inner layer of the chorionic villi...
can make cells
VSD
Prenatal and perinatal
4th/5th branchial pouches
33. From What embryonic lare are the odontoblasts from?
Umbilical - midgut herniates through umbilical ring; SMA
Diencephalon
1st cleft/groove (Ectoderm)
Neural crest cells
34. Which CN allows for taste and sensation in the posterior 1/3 of the tongue? how about the very back ?
Ventral; failure of urogenital folds to close
Arches 3 and 4
IX; X
Muscular ventricular septum; no
35. Where is the most common ectopic thyroid tissue?
Tongue
Dorsal; faulty positioning of genital tubercle
Mesoderm
From endocardial cushions (ventral and dorsal meet each other)
36. Gastroschisis is extrusion of abdominal contents out of abdominal folds ___________ by peritoneum
Mesoderm
Outgrowth of mesonephric as ureteric bud; most caudal
IMA
not covered
37. From where is the pancreas derived? the spleen?
1st
Amniotic epithelium
Surface ectoderm
Foregut; dorsal mesentery (mesodermal)
38. Which branchial derivative accounts for the posterior 2/3 of the tongue?
3rd and 4th arches
Yolk sac; 3rd week
primary palate
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
39. Only _______________________________ are associated with neural tube defects
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
Metencephalon; cerebellum
arnold chiari associated with thoraclumbar myelomeningocele
40. From what region do the thalami form?
Failure of the urachus to obliterate; outpouching of the bladder
Diencephalon
1st
Neuroectoderm
41. From What embryonic layer does the neurohypophysis arise?
Neuroectoderm
Pataus; fetal alcohol syndrome
hypospadias
Week 8
42. What causes the transposition of the great vessels? What does it result in?
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
Fluid filled cavity in spinal cord; C8- T1; arnold chiari II
Mesoderm
Skewed development of AP septum
43. What part of the vagina does the mullerian duct form? Where does the rest come from?
Rostral fold closure ; lateral fold closure; lateral fold closure; caudal fold closure
Muscles and arteries
Synctiotrophoblast; outer; no
Upper 1/3; urogenital sinus
44. What embryological structure gives rise to the trabeculated part of the left and right atrium?
Annular pancrease
Primitive atrium
Neuroectoderm
Week 4
45. What does the ureteric bud interact with and What does it induce it to become?
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
Mesencephalon
Duodenum to transverse colon; distal transverse colon to rectum
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3
46. What trisomy is associated with holoprosencephaly? What teratogen?
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)
Neural crest cells
Initial left to right shunting - then switches
Pataus; fetal alcohol syndrome
47. Name a syndrome cleft palate is often seen in
DiGeorge
Indomethacin; blocks PG production
Dorsal and ventral buds
Fluid filled syrinx causes expansion and degeneration of cord tracts
48. From where does the medulla form?
1st cleft/groove (Ectoderm)
5th
Myelencephalon
Oligohydramnios
49. From What embryonic layer do the ependymal cells arise?
Neuroectoderm
4th week
Decreases
Scrotum; labia majora
50. Where is sonic hedgehog gene produced? What axis is it responsible in patterning?
Annular pancrease
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Neural crest cells
Base of limbs in the zone of polarizing activity; ant - post