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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 embryonic layer does the pineal gland arise?
Hypertrophy of muscularis externis of pylorus; surgical incision
ACE inhibitors - HCTZ
Neuroectoderm
Neural crest cells
2. How do you differentiate a thyroglossal duct cyst from a persistent cervical sinus?
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
Failure of the urachus to obliterate; outpouching of the bladder
Metencephalon; cerebellum
Fetal and maternal
3. When does the notochord form? and When does the neural plate form?
DHT; estrogen
monoamniotic
80%
Mesoderm; 3 week
4. During what week do the limbs begin to form?
Initial left to right shunting - then switches
Thyroid - cricoid - arytenoids - corniculate cuneiform
Week 4
Neuroectoderm
5. What is the effect of teratogens before week 3?
All or none
DHT; estrogen
Deoxygenated blood; fetal internal iliac arteries to placenta
First branchial pouch
6. What is congenital pharyngocutaneous fistula? and How does it occur?
not covered
Sonic Hedgehog
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
Epispadias
7. For what reason do hypospadias need to be fixed?
Prevent recurrent UTIs
During; instrinsic
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
Mid gut to yolk sac; omphalomesenteric duct; 7th week
8. what happens in hydrocele?
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
Thyroid - cricoid - arytenoids - corniculate cuneiform
Tunica vaginalis not fully fused
All or none
9. Cleft palate is a failure of formation of the...
Week 3-8
secondary palate
When left to right shunting switching to right to left shunting
Annular pancrease
10. From where does the signal come from to suppress paramesonephric ducts? what stimulates development of the mesonephric ducts?
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
Mullerian inhibitory factor from Sertoli cells; increased androgen from Leydig cells
ACE inhibitors - HCTZ
Common carotid and internal carotid
11. By what week is the neural tube supposed to be closed? when did it start forming?
Week 10-12; end of 1st trimester
Mesencephalon
Week 4; week 3
Folate antagonists
12. What are the three results of having pathology in the aorticopulmonary septum?
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)
Synctiotrophoblast
Nutrient and gas for exchange; endometrium
Amniotic epithelium
13. what bone/cartilage and nerves are derived from branchial arch 3?
Greater horn of hyoid; CN IX (styloPharyngeus)
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
Surface ectoderm
Oxygenated; placenta to fetus (IVC)
14. What does the vitelline duct connect? What is it also known as? when should it obliterate?
Mid gut to yolk sac; omphalomesenteric duct; 7th week
A vitelline fistula - failure of vitelline duct to close
6th aortic arch
hypospadias
15. What type of blood do umbilical veins carry? From where to where?
Oxygenated; placenta to fetus (IVC)
Congenital and chromosomal abnormalities
Rostral fold closure ; lateral fold closure; lateral fold closure; caudal fold closure
Cytotrophoblast
16. From where does pons form from? what else forms from there?
Metencephalon; cerebellum
Obliterated; forms tunica vaginalis
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
Week 8
17. which teratogen can cause Ebsteins anomaly in the fetus?
Surface ectoderm
Lithium
Endoderm
Bulbos Cordis; right ventricle entirely
18. What teratogens can cause renal damage in the fetus?
Allantois
ACE inhibitors - HCTZ
1st
Surface ectoderm
19. What is the effect of teratogens after week 8?
Rhombencephalon
Cerebellar tonsillar herniation through foramen magnum
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
Deformation
20. Which part of pancreas contribute to body? tail? isthmus? accessory pancreatic duct?
Week 3-8
Neuroectoderm
Ventral bud
Oxygenated; placenta to fetus (IVC)
21. failure to close of what fold results in sternal defects? omphalocele? gastrochisis? bladder extrosphy?
Incomplete; yes
Rostral fold closure ; lateral fold closure; lateral fold closure; caudal fold closure
Neural crest cells
Day 6; with implantation
22. What is a zygote?
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
Neuroectoderm
Sperm plus egg
Nutrient and gas exchange
23. What layer is the epiblast? hypoblast?
Endoderm
Fetal alcohol syndrome; mental retardation
Ectoderm; endoderm
Mesoderm; nucleous pulposos
24. 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?
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
Synctiotrophoblast; outer; no
StyloPharyngeus
Mesoderm; epiblast
25. What are the neural crest cells and where do they come form? where do they go?
Thickened ectoderm at end of each developing limb
Fallopian tube - uterus - upper 1/3 of vagina
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
They are the edge of neural plate folding; all over the body
26. What is the prochordal plate?
Annular pancrease
Surface ectoderm
Where the epiblast and hypoblast fuse
Ventral; failure of urogenital folds to close
27. What is holoprosencephaly? what eye disorder does it result in?
Maxillary and medial nasal processes
Decreased separation of hemispheres across midline; cyclopia
DiGeorge
Pataus; fetal alcohol syndrome
28. From What do the embryoblast and trophoblast form from? What does the embryoblast split into? the trophoblast?
Mesoderm
Occiptal
lumbosacral
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
29. How do adults with annular pancreas present? and At What age?
Endoderm
20-50yrs - Abdominal pain - Postprandial fullness - Nausea - Peptic ulcers - Pancreatitis - Rarely - biliary obstruction
Mesoderm
Wolffian; mullerian
30. From what region of the brain does the aqueduct form?
Rhombencephalon
Fetal alcohol syndrome; mental retardation
Renal artery stenosis;
20-50yrs - Abdominal pain - Postprandial fullness - Nausea - Peptic ulcers - Pancreatitis - Rarely - biliary obstruction
31. What germ layer correlates with the branchial pouches?
Increase in oxygen concentration which decreases prostaglandin concentration
Ectoderm
Endoderm
Increased AFP and acetycholinesterase (not ACh!) in CSF
32. What surrounds the umbilical cord?
Amniotic epithelium
Folate antagonists
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
Physiologic incomplete muscular ventricular septum
33. What part of the vagina does the mullerian duct form? Where does the rest come from?
Metencephalon; cerebellum
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
Upper 1/3; urogenital sinus
Obliterated; forms tunica vaginalis
34. is epispadias or hypospadias associated with exstrophy of the bladder?
Truncus arteriosus; pulmonary trunk
A vitelline fistula - failure of vitelline duct to close
Neural crest cells
Epispadias
35. What does DHT turn the urogenital sinus into? estrogen?
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
Day 6; with implantation
Endoderm
Neural crest cells
36. Which branchial apparatus makes the external auditory meatus?
Mesoderm; 3 week
1st cleft/groove (Ectoderm)
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
80%
37. what bone/cartilage and nerves are derived from branchial arch 1?
Primitive atrium
ACE inhibitors - HCTZ
Mesoderm
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
38. What are markers for neural tube defects in the amniotic cavity? CSF?
VACTERL- vertebral defect - anal atresia - cardiac defects - tracheo - esophageal fistula - renal defects - limb defects
Tongue
Increased AFP and acetycholinesterase (not ACh!) in CSF
Sperm plus egg
39. The spleen is ____________ in origin and supplied by a foregut artery
mesodermal
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
6th aortic arch
VACTERL- vertebral defect - anal atresia - cardiac defects - tracheo - esophageal fistula - renal defects - limb defects
40. How many umbilical arteries are there? How many umbilical veins?
Before getting pregnant!
Rhombencephalon
2; 1
Bone/cartilage and nerves
41. From where does the permanent kidney for? is it most caudal or most cranial?
VACTERL- vertebral defect - anal atresia - cardiac defects - tracheo - esophageal fistula - renal defects - limb defects
Prosencephalon
Branchial arch 2
Outgrowth of mesonephric as ureteric bud; most caudal
42. When does the neural tube form and From what does it form?
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
Cerebellar tonsillar herniation through foramen magnum
Neural plate; closes by week 4
Spinothalamic first
43. What two things cause VACTERL syndrome?
Prevent recurrent UTIs
Mesoderm
Maxillary
OCPS and maternal diabetes
44. what else is the caudal regression known as? What two teratogen can cause this in the fetus?
VACTERL; OCPs and maternal diabetes
Endoderm
Week 4
monoamniotic
45. Where is the most common ectopic thyroid tissue?
External auditory meatus
A vitelline fistula - failure of vitelline duct to close
Tongue
Week 3-8
46. What congenital abnormality forms a 'double bubble' on xray?
Annular pancrease
4th arch; 6th arch
Scrotum; labia majora
Surface ectoderm
47. What embryologic structure provides the aorticpulmonary septum?
Mesoderm
Neural crest migration - they then cause spiral
Muscular ventricular septum; no
Neural crest cells
48. Most myelomeningoceles present in the _______ region
Ventral shaft of penis (penile urethra); labia minora
Neural crest cells
Surface ectoderm
lumbosacral
49. What happens in pancreas divisum? what results?
Base of limbs in the zone of polarizing activity; ant - post
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
50. Monochorionic - ___________ twins are conjoined
monoamniotic
Female; paramesonephric; mesonephric
Skewed development of AP septum
Ectoderm