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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 artery is derived branchial (aortic) arch 2?
Stapedius and hyoid artery
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
Base of limbs in the zone of polarizing activity; ant - post
Mesoderm
2. 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?
Neuroectoderm
Excessive resorption of septum primum or secondum (or both)
2; 1
Synctiotrophoblast; outer; no
3. With the first breath the infant take - pulmonary vasculature resistance _______ which causes an increase in left atrial pressure
Yolk sac; 3rd week
OCPS and maternal diabetes
Decreases
No more umbilical circulation emptying into RA
4. What artery is derived branchial (aortic) arch 3?
4th week
Congenital and chromosomal abnormalities
Surface ectoderm
Common carotid and internal carotid
5. From what are the umbilical arteries and veins derived from?
Week 8
Skewed development of AP septum
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3
Allantois
6. What does DHT turn the urogenital folds into? estrogen?
Ventral shaft of penis (penile urethra); labia minora
Decreased pulmonary resistance in the pulmonary vasculature
Common carotid and internal carotid
Endoderm
7. What is annular pancreas associated with in infants?
Congenital and chromosomal abnormalities
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
Foramen cecum and terminal sulus
Midgut; 10th week
8. What does the maternal component of the placenta provide? Where is it derived from?
Alkylating agents
Prenatal and perinatal
Nutrient and gas for exchange; endometrium
6-30
9. Which branchial arch derivative is obliterated?
Epiblast
Embryonic period; 1st trimester
lumbosacral
5th
10. what other facial defect other than cyclopia is associated with holoprosencephaly?
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
Cleft lip/palate
Surface ectoderm
Mesoderm; nucleous pulposos
11. From What embryonic layer do the ANS arise?
Neuroectoderm
Neural crest cells
Polyhydramnios
Mesdoerm
12. What is jejunal - ileal - colonic atresia usually due to? What do you see on x ray?
Neural crest cells
Vascular accident intra uterine; apple peel atresia
Surface ectoderm
Ampulla
13. What does the vitelline duct connect? What is it also known as? when should it obliterate?
Pulm art (prox) and ductus arteriosus
Neuroectoderm
Mid gut to yolk sac; omphalomesenteric duct; 7th week
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
14. What trisomy is associated with holoprosencephaly? What teratogen?
Pataus; fetal alcohol syndrome
Prosencephalon
8
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
15. From where does the prostate develop? seminal vesicles? fallopian tube? lower 2/3 of the vagina? ejaculatory duct? epididymis? uterus? upper 1/3 of the vagina?
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
Neural crest cells
Congenital and chromosomal abnormalities
Neuroectoderm
16. What do the groove/clefts of the branchial apparatus correlate to?
Turners; inferior
Before getting pregnant!
Where the epiblast and hypoblast fuse
Ectoderm
17. what structures are the derivatives of the neural crest cells in branchial arches?
Day 6; with implantation
6-30
Neural crest cells
Bone/cartilage and nerves
18. 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?
Pataus; fetal alcohol syndrome
Bones - cartilage - and nerves
From endocardial cushions (ventral and dorsal meet each other)
Arnold Chiari and Dandy Walker; Arnold Chiari; Dandy Walker; Arnold Chiari
19. What results in annular pancreas? How does it happen?
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
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
Found in lateral neck; from no obliteration of 2-4th clefts
20. From what arches are the neural crest cells that form the aorticpulmonary septum derived?
Mid gut to yolk sac; omphalomesenteric duct; 7th week
Obliterated; forms tunica vaginalis
3 -4 -6
Maxillary
21. What is the effect of teratogens before week 3?
Week 8
Neural crest migration - they then cause spiral
All or none
Mesoderm
22. WithIn what week does gastrulation occur? What is gastrulation?
lumbosacral
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Sonic Hedgehog
Week 3; primitive streak formation from the epiblast makes the three layers
23. Which part of pancreas contribute to body? tail? isthmus? accessory pancreatic duct?
3rd pouch
Ventral bud
Primitive atrium
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
24. From where do the three different kidneys come from? Which is the earliest one? is it located most cranially or caudally?
Pronephros - mesonephros - metanephros; pronephros; most cranially
2nd; 2nd
4th pouch
Fluid filled cavity in spinal cord; C8- T1; arnold chiari II
25. From What embryonic layer do CNS neurons arise?
Neuroectoderm
Pataus; fetal alcohol syndrome
Foregut; dorsal mesentery (mesodermal)
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
26. From what aortic arch does the common carotid artery arise? what else arises from this arch?
When left to right shunting switching to right to left shunting
Grooves/clefts; arches; pouches
3
3rd; proximal part of the internal carotid artery
27. What is the effect of teratogens after week 8?
Endoderm
Physiologic incomplete muscular ventricular septum
Week 8
Deformation
28. What is hypoplasia? is primordial tissue present?
Mesoderm
Incomplete; yes
Dorsal and ventral buds
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
29. Which branchial derivative accounts for taste in the ant 2/3?
Bone/cartilage and nerves
Neuroectoderm
Primitive atrium
Branchial arch 2
30. Cleft palate is a failure of fusion of the lateral palatine processes - the nasal septum and or the ________?
Medial palatine processes
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
elevated AFP
31. What happens in pancreas divisum? what results?
Neural crest cells
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Neural crest cells
Stapedius and hyoid artery
32. From What embryonic layer does the sensory organs of the ear arise?
Surface ectoderm
All or none
Wolffian; mullerian
Mid gut to yolk sac; omphalomesenteric duct; 7th week
33. Which branchial derivative creates the epithelial lining of the palatine tonsils?
2nd pouch
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
Nutrient and gas exchange
Ebsteins anomaly; tricuspid atresia
34. What teratogen can cause an absence of digits amongst other things in the fetus? give an example.
Left horn of the sinus venosus
4th arch; 6th arch
Ionizing
Alkylating agents
35. From where is amniotic fluid produced? other than electrolytes and carbs - what else does it contain?
No more umbilical circulation emptying into RA
Rhombencephalon
Maternally derived; meconium
Decreased separation of hemispheres across midline; cyclopia
36. What day is the chorion formed?
3
3 -4 -6
Cerebral hemisphere - thalami
Ionizing
37. From what region does the midbrain form from?
Vascular accident intra uterine; apple peel atresia
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
Cerebral hemisphere - thalami
Mesencephalon
38. What causes a large posterior fossa in a dandy walker malformation? What is found in this fossa?
not covered
Absent cerebellar vermis; cystic enlargement of 4th ventricle
Surface ectoderm
Endocardial cushions
39. From What embryonic layer does the brain arise?
primary palate
Prosencephalon - mesencephalon - rhombencephalon
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
Neuroectoderm
40. From What embryonic layer do chromaffin cells arise?
Obliterated; forms tunica vaginalis
Week 4
Neural crest cells
Week 3-8
41. What does DHT turn the urogenital sinus into? estrogen?
Dorsal; faulty positioning of genital tubercle
LH
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
Greater horn of hyoid; CN IX (styloPharyngeus)
42. What components do the neural crest cells of the branchial arches give rise to?
Cleft lip/palate
Aortic arch (from left side); right subclavian (on the right)
4th week
Bones - cartilage - and nerves
43. what junction is the last to canalize? what implications does this have down the line?
ACE inhibitors - HCTZ
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
They are the edge of neural plate folding; all over the body
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
44. What does the mullerian duct develop into? wollffian?
Fallopian tube - uterus - upper 1/3 of vagina
Neuroectoderm
4th pouch
ACE inhibitors - HCTZ
45. From What embryonic layer is the vagina from? testes? ovaries?
Amniotic cavity and yolk sac
Mesoderm
Failure of bony spinal canal to fuse; no; lower vertebral levels
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
46. From What embryonic layer are the melanocytes from?
Neural crest cells
Week 3-8
Absent cerebellar vermis; cystic enlargement of 4th ventricle
Week 2; bilaminar disk; epiblast and hypoblast
47. what bone/cartilage and nerves are derived from branchial arch 1?
Cerebellar tonsillar herniation through foramen magnum
Endoderm
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
3 -4 -6
48. What does the RET gene encode? what neoplasias is it associated with?
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
Increase in oxygen concentration which decreases prostaglandin concentration
Neuroectoderm
49. What is an arnold chiari II malformation? through what hole does it herniate?
Week 10-12; end of 1st trimester
Polyhydramnios
Hepatic circulation; ligamentum venosum
Cerebellar tonsillar herniation through foramen magnum
50. Name a syndrome cleft palate is often seen in
Neural crest cells
Failure to recanalize; 21
DiGeorge
Failure of the urachus to obliterate