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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 notochord? What does the notochord later become?
Primitive atrium
Mesoderm; nucleous pulposos
Aortic arch (from left side); right subclavian (on the right)
3
2. What causes a large posterior fossa in a dandy walker malformation? What is found in this fossa?
Nutrient and gas for exchange; endometrium
Right horn of the SV
Neural crest cells
Absent cerebellar vermis; cystic enlargement of 4th ventricle
3. what week do the genitalia start to have male/female characteristics? What trimester is that?
Mesoderm
Neural crest cells
Endoderm
Week 10-12; end of 1st trimester
4. What arises from the fourth aortic arch?
Aortic arch (from left side); right subclavian (on the right)
Mesoderm
All or none
Nicotine; preterm labor
5. What is used to keep the PDA open?
Prostaglandins
6th aortic arch
XII
Allantois
6. Does deformation occur during or after the embryonic period? is it due to an extrinsic or intrinsic disruption?
Tetracyclines
Neural crest cells
After; extrinsic
Ectoderm
7. When is most important to take folic acid to prevent neural tube defects?
Before getting pregnant!
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
3rd pouch
not covered
8. What separated myometrium of the uterus from the blastocyst?
Deformation
Decidual basalis
Synctiotrophoblast; outer; no
80%
9. Which branchial derivative creates the epithelial lining of the palatine tonsils?
Ventral shaft of penis (penile urethra); labia minora
Prevent recurrent UTIs
Absent cerebellar vermis; cystic enlargement of 4th ventricle
2nd pouch
10. what chemo drugs can cause neural tube defects in the fetus?
Folate antagonists
DHT; estrogen
Metencephalon; cerebellum
Surface ectoderm
11. Where is the decidua basalis derived from?
Absent cerebellar vermis; cystic enlargement of 4th ventricle
ACE inhibitors - HCTZ
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
Endometrium
12. What is the female remnant of the gubernaculum? male remnant?
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
Epiblast
Thalidomide; nausea
Decreased pulmonary resistance in the pulmonary vasculature
13. When does hcG get secreted? What does it do?up until when ?
Day 6; maintains corpus luteum; 1st trimester
2; 1
Deformation
Week 10-12; end of 1st trimester
14. Which branchial arch derivative is obliterated?
5th
Ventral ; motor
Thyroid - cricoid - arytenoids - corniculate cuneiform
2nd pouch
15. failure to close of what fold results in sternal defects? omphalocele? gastrochisis? bladder extrosphy?
Primitive ventricle
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
Rostral fold closure ; lateral fold closure; lateral fold closure; caudal fold closure
Obliterated; forms tunica vaginalis
16. From What embryonic layer does the spinal cord arise?
Cerebral hemisphere - thalami
Bones - cartilage - and nerves
Mesoderm
Neuroectoderm
17. What embryologic structure gives rise to the smooth outflow tracts of the ventricles? what else does it give rise to?
Medial palatine processes
Bulbos Cordis; right ventricle entirely
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
4th arch; 6th arch
18. In anencephaly you see...
Left horn of the sinus venosus
Neuroectoderm
elevated AFP
Oxygenated; placenta to fetus (IVC)
19. 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
Nicotine; preterm labor
Endoderm
When left to right shunting switching to right to left shunting
20. Cleft palate is a failure of formation of the...
Failure of the urachus to obliterate
secondary palate
Pulm art (prox) and ductus arteriosus
Greater horn of hyoid; CN IX (styloPharyngeus)
21. What do the groove/clefts of the branchial apparatus correlate to?
Day 6; with implantation
Decreased pulmonary resistance in the pulmonary vasculature
Ectoderm
Germinal matrix hemorrhage
22. From which myotomes are muscles of the tongue derived from?
Oligohydramnios
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
Obliterated
Occiptal
23. From What embryonic layer does the adenohypophysis arise?
LH
Surface ectoderm
From teh lung;blood from IVC in RA to LA; fossa ovalis
DiGeorge
24. The spinal cord is made from...
Nicotine; preterm labor
T neuroectoderm
Congenital and chromosomal abnormalities
Tongue
25. What do the arches of the branchial apparatus correlate to?
Mesdoerm
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
Failure of bony spinal canal to fuse; no; lower vertebral levels
Neural crest cells
26. What day is the chorion formed?
2; 1
3
Ventral bud
2nd pouch
27. From What embryonic layer does the parathyroid arise ?
Foramen cecum and terminal sulus
Ventral bud
Endoderm
Rostral fold closure ; lateral fold closure; lateral fold closure; caudal fold closure
28. What do membranous interventricular septal defect cause? What does this lead to?
Lacunae in between the chorionic villi
Initial left to right shunting - then switches
Fetal alcohol syndrome; mental retardation
Umbilical - midgut herniates through umbilical ring; SMA
29. what separates the atria from the ventricles?
Ventral; failure of urogenital folds to close
DHT; estrogen
Endocardial cushions
2nd pouch
30. What is the leading cause of birth defects in the US? what else is this perpetrator the leading cause of?
T neuroectoderm
Primitive ventricle
Fetal alcohol syndrome; mental retardation
Urachus/median umbilical ligament; bladder and yolk sac
31. Other than not having a brain - what else is a symptom of anencephaly? why? hint: think about amniotic fluid
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
Ebsteins anomaly; tricuspid atresia
Polyhydramnios
arnold chiari associated with thoraclumbar myelomeningocele
32. What does the ureteric bud interact with and What does it induce it to become?
Bones - cartilage - and nerves
Neural crest cells
VACTERL- vertebral defect - anal atresia - cardiac defects - tracheo - esophageal fistula - renal defects - limb defects
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
33. What does DHT turn the urogenital sinus into? estrogen?
IX; X
Spinothalamic first
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
Neural crest cells
34. From what aortic arch does the first part of the maxillary artery arise?
1st
DiGeorge
Upper 1/3; urogenital sinus
Pronephros - mesonephros - metanephros; pronephros; most cranially
35. From What embryonic layer is the vagina from? testes? ovaries?
Endoderm
Occiptal
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
Mesoderm
36. When does the blastocyst split into two disks? What is this disk called? What are the two germ layers called?
Upper 1/3; urogenital sinus
Week 2; bilaminar disk; epiblast and hypoblast
Aminoglycosides
Female; paramesonephric; mesonephric
37. which tracts are damaged first in syringomelia? What tract is preserved?
Spinothalamic first
Skewed development of AP septum
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
Folate antagonists
38. What is the effect of teratogens before week 3?
All or none
20-50yrs - Abdominal pain - Postprandial fullness - Nausea - Peptic ulcers - Pancreatitis - Rarely - biliary obstruction
Occiptal
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
39. From where is amniotic fluid produced? other than electrolytes and carbs - what else does it contain?
Rostral fold closure ; lateral fold closure; lateral fold closure; caudal fold closure
Skewed development of AP septum
Valproate acid
Maternally derived; meconium
40. From What embryonic layer does the lens of the eye arise?
Neuroectoderm
Lacunae in between the chorionic villi
Synctiotrophoblast; outer; no
Surface ectoderm
41. What is the kidney that functions at the interim kidney in the 1st trimester? What does it later contribute to?
Germinal matrix hemorrhage
Bulbos Cordis; right ventricle entirely
Mesonephros; male genital system
Incomplete fusion of paramesonephric ducts; UT abnormalities and infertility
42. Which is more common - epispadias or hypospadias?
Right common cardinal vein and right anterior cardinal vein
Hypospadias
Cleft lip/palate
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
43. From where does the medulla form?
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
Mesoderm
Myelencephalon
Mesdoerm
44. What is the 'fetal period'- ie When is it?
First branchial pouch
Gastric outlet obstruction (bilious vomiting - feeding intolerance - abdominal distention)
Week 8
Congenital and chromosomal abnormalities
45. What hormone is hcG structurally similar too?
3rd; proximal part of the internal carotid artery
hypospadias
Obliterated
LH
46. What does the first branchial pouch create?
Stapedius and hyoid artery
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Hypospadias
Decreased pulmonary resistance in the pulmonary vasculature
47. From what aortic arch does the stapedial artery arise? the hyoid?
Obliterated; forms tunica vaginalis
lumbosacral
2nd; 2nd
6th aortic arch
48. what happens in hydrocele?
Tunica vaginalis not fully fused
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
Respiratory distress syndrome
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
49. what closes the interventricular foramen?
Physiologic incomplete muscular ventricular septum
Endoderm
Stapedius and hyoid artery
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
50. What is contained in the umbilical cord?
Pulm art (prox) and ductus arteriosus
Endoderm
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
...