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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 invaginates to form the primitive streak?
Epiblast
When left to right shunting switching to right to left shunting
Stapedius and hyoid artery
3rd; proximal part of the internal carotid artery
2. What connects the thyroid to the tongue? when happens if it doesnt obliterate?
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
Surface ectoderm
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
3. Cleft lip is a failure of fusion of ________ and ______.
Maxillary and medial nasal processes
Umbilical - midgut herniates through umbilical ring; SMA
Deformation
Mesoderm
4. What embryonic structure gives rise to the ascending aorta? what else does it give rise to?
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
Endocardial cushions
Truncus arteriosus; pulmonary trunk
Thickened ectoderm at end of each developing limb
5. What components do the neural crest cells of the branchial arches give rise to?
Valproate acid
Initial left to right shunting - then switches
Bones - cartilage - and nerves
Mesdoerm
6. From What embryonic layer does the retina arise?
Endoderm
Endocardial cushions
Neuroectoderm
monoamniotic
7. Where is the FGF gene produced? What is it responsible for - How does it do this?
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
Fluid filled cavity in spinal cord; C8- T1; arnold chiari II
No organ in each; agenesis no primordial tissue
Neuroectoderm
8. From What embryonic layer do the ANS arise?
blood entering the RA
Skewed development of AP septum
Neural crest cells
Synctiotrophoblast; outer; no
9. What is the Eisenmeger complex?
1st cleft/groove (Ectoderm)
...
When left to right shunting switching to right to left shunting
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
10. From What embryonic layer does bone of the skulls arise?
Hemorrhage - bone deformities
Week 2; bilaminar disk; epiblast and hypoblast
Neural crest cells
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
11. Where does fertilization occur?
Ampulla
hypertrophy
IX; X
Lots - cleft palate/lip
12. From what arches are the neural crest cells that form the aorticpulmonary septum derived?
...
3 -4 -6
Mesoderm
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
13. During what week do the limbs begin to form?
Endoderm
Ventral shaft of penis (penile urethra); labia minora
Week 4
First branchial pouch
14. What embryological structure gives rise to the coronary sinus?
Incomplete; yes
Left horn of the sinus venosus
T neuroectoderm
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
15. Which branchial derivative creates the middle ear cavity - eustachian tube and mastoid air cells?
Initial left to right shunting - then switches
First branchial pouch
Neural crest cells
Mesoderm
16. When does hcG get secreted? What does it do?up until when ?
Day 6; maintains corpus luteum; 1st trimester
Greater horn of hyoid; CN IX (styloPharyngeus)
Mesoderm
Endoderm
17. To what germ layer does the branchial pouches correlate to?
Cranio - caudal; segmental
...
Mesoderm
Endoderm
18. When is most important to take folic acid to prevent neural tube defects?
A vitelline fistula - failure of vitelline duct to close
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)
Before getting pregnant!
Folate antagonists
19. What are the two components of the placenta? From What do they form? which one secreted hcG?
...
Arches 3 and 4
Greater horn of hyoid; CN IX (styloPharyngeus)
Dorsal ventral axis
20. What artery is derived branchial (aortic) arch 4?
Hemorrhage - bone deformities
Mesencephalon
elevated AFP
Aortic arch and prox part of subclavian
21. What effect does warfarin have on the fetus?
Initial left to right shunting - then switches
4th/5th branchial pouches
Telencephalon
Hemorrhage - bone deformities
22. in hypospadias - on which side is the abnormal opening? What causes it?
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Ventral; failure of urogenital folds to close
3rd; proximal part of the internal carotid artery
Arnold Chiari and Dandy Walker; Arnold Chiari; Dandy Walker; Arnold Chiari
23. what closes the interventricular foramen?
Neuroectoderm
5th
Physiologic incomplete muscular ventricular septum
Maxillary and medial nasal processes
24. Name a syndrome cleft palate is often seen in
DiGeorge
Amniotic epithelium
septum primum and/or secundum
From teh lung;blood from IVC in RA to LA; fossa ovalis
25. From what region do the thalami form?
Medial palatine processes
Fluid filled syrinx causes expansion and degeneration of cord tracts
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
Diencephalon
26. Septum primum (patent foramen oval) caused by excessive resorption of...
VACTERL; OCPs and maternal diabetes
Primitive atrium
septum primum and/or secundum
Ectoderm
27. What trisomy is associated with holoprosencephaly? What teratogen?
Valproate acid
Pataus; fetal alcohol syndrome
elevated AFP
Absent cerebellar vermis; cystic enlargement of 4th ventricle
28. In what chromosomal disorder is horseshoe kidney commonly seen? what poles of the kidneys fuse?
Turners; inferior
VSD
Decreased separation of hemispheres across midline; cyclopia
Ectoderm; endoderm
29. What do the arches of the branchial apparatus correlate to?
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
Neural crest cells
Mesdoerm
Surface ectoderm
30. During what week does the heart begin to beat?
Endocardial cushions
Week 4
Found in lateral neck; from no obliteration of 2-4th clefts
Pronephros - mesonephros - metanephros; pronephros; most cranially
31. When does the notochord form? and When does the neural plate form?
Incomplete; yes
Umbilical - midgut herniates through umbilical ring; SMA
Mesoderm; 3 week
Female; paramesonephric; mesonephric
32. what results if they dont? What can increase the risks of this?
Sperm plus egg
6th aortic arch
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
Persistent connection between amniotic cavity and spinal canal; low folic acid
33. What are the neural crest cells and where do they come form? where do they go?
Mesoderm
Fetal alcohol syndrome; mental retardation
elevated AFP
They are the edge of neural plate folding; all over the body
34. What separated myometrium of the uterus from the blastocyst?
IX; X
Decidual basalis
Congenital and chromosomal abnormalities
80%
35. What is omphalocele? In What trisomies is it seen?
Obliterated
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
36. What does DHT turn the labioscrotal swelling into? estrogen?
Fluid filled cavity in spinal cord; C8- T1; arnold chiari II
Week 10-12; end of 1st trimester
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Scrotum; labia majora
37. What happens in pancreas divisum? what results?
Left horn of the sinus venosus
Endoderm
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
septum primum and/or secundum
38. What is duodenal atresia usually due to? What trisomy is it most often seen in?
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
Greater horn of hyoid; CN IX (styloPharyngeus)
Failure to recanalize; 21
No more umbilical circulation emptying into RA
39. Blood coming in the umbilical vein is ____ saturated
Ventral ; motor
80%
Increase in oxygen concentration which decreases prostaglandin concentration
Dorsal ventral axis
40. From what does bicornuate uterus arise? What is it associated with?
Arches 3 and 4
Yolk sac; 3rd week
Incomplete fusion of paramesonephric ducts; UT abnormalities and infertility
Aortic arch and prox part of subclavian
41. From What embryonic layer is the eustachian tube from?
Urachus/median umbilical ligament; bladder and yolk sac
Germinal matrix hemorrhage
Mesoderm
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
42. What causes a large posterior fossa in a dandy walker malformation? What is found in this fossa?
After; extrinsic
Absent cerebellar vermis; cystic enlargement of 4th ventricle
Amniotic epithelium
Neural crest cells
43. The inner layer of the chorionic villi...
Neural crest cells
can make cells
Diencephalon
Incomplete fusion of paramesonephric ducts; UT abnormalities and infertility
44. What causes meconium discharge from the umbilicus?
No more umbilical circulation emptying into RA
Greater horn of hyoid; CN IX (styloPharyngeus)
Decreased pulmonary resistance in the pulmonary vasculature
A vitelline fistula - failure of vitelline duct to close
45. what other facial defect other than cyclopia is associated with holoprosencephaly?
Mid gut to yolk sac; omphalomesenteric duct; 7th week
Neural crest cells
1st cleft/groove (Ectoderm)
Cleft lip/palate
46. what bone/cartilage and nerves are derived from branchial arch 1?
Neural crest cells
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Synctiotrophoblast; outer; no
Mesoderm; 3 week
47. is epispadias or hypospadias associated with exstrophy of the bladder?
Muscular ventricular septum; no
Fetal and maternal
Epispadias
Synctiotrophoblast; outer; no
48. What are the two components of the fetal component of the placenta?
can make cells
Mesoderm
Cytotrophoblast and synctiotrophoblast
Mesoderm
49. Does malformation occur during or after the embryonic period? is it due to an extrinsic or intrinsic disruption?
ACE inhibitors - HCTZ
During; instrinsic
Absent cerebellar vermis; cystic enlargement of 4th ventricle
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
50. What part of the vagina does the mullerian duct form? Where does the rest come from?
Week 4
Ectoderm
Neuroectoderm
Upper 1/3; urogenital sinus