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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 holoprosencephaly? what eye disorder does it result in?
Decreased separation of hemispheres across midline; cyclopia
Ventral bud
5th
Mesdoerm
2. From What embryonic layer does bone of the skulls arise?
Ectoderm; endoderm
Pharynx to duodenum; duodenum to transverse colon; distal transverse colon to rectum
Neural crest cells
DHT; estrogen
3. From what region of the brain does the aqueduct form?
Rhombencephalon
Lacunae in between the chorionic villi
Absent cerebellar vermis; cystic enlargement of 4th ventricle
Yolk sac; 3rd week
4. What is the leading cause of birth defects in the US? what else is this perpetrator the leading cause of?
Fetal alcohol syndrome; mental retardation
Synctiotrophoblast; outer; no
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
5. From What do the embryoblast and trophoblast form from? What does the embryoblast split into? the trophoblast?
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Synctiotrophoblast
Week 2; bilaminar disk; epiblast and hypoblast
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
6. What artery is derived branchial (aortic) arch 1?
Surface ectoderm
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
Maxillary
7. What connects the thyroid to the tongue? when happens if it doesnt obliterate?
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
Prevent recurrent UTIs
SRY gene on Y chromosomes; sertoli and leydi; MIF and androgens; suppression of paramesonephric ducts and dev. of mesonephric (all respectively)
Folate antagonists
8. From What embryonic layer does the epidermis arise?
Surface ectoderm
Rhombencephalon
Neuroectoderm
Arnold Chiari and Dandy Walker; Arnold Chiari; Dandy Walker; Arnold Chiari
9. What causes tetralogy of Fallot?
2; 1
Mesoderm
Skewed development of AP septum
Annular pancrease
10. From What embryonic layer do the ependymal cells arise?
IMA
Neuroectoderm
Temporary cervical sinus
5th
11. The spinal cord is made from...
Arnold chiari; syringomyelia
T neuroectoderm
Maxillary
IMA
12. Which branchial apparatus develops into the thymus?
Week 3-8
3rd pouch
Decreases
septum primum and/or secundum
13. What does the RET gene encode? what neoplasias is it associated with?
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
Surface ectoderm
Week 4
Lacunae in between the chorionic villi
14. What is congenital pharyngocutaneous fistula? and How does it occur?
Mesoderm
Neural crest cells
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
15. 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?
Aortic arch and prox part of subclavian
hypospadias
monoamniotic
Arnold Chiari and Dandy Walker; Arnold Chiari; Dandy Walker; Arnold Chiari
16. Only _______________________________ are associated with neural tube defects
Cerebellar tonsillar herniation through foramen magnum
arnold chiari associated with thoraclumbar myelomeningocele
Yolk sac; 3rd week
hypospadias
17. What is the mcc of renovascular hypertension in children? What does this predispose to?
Week 8
Renal artery stenosis;
1st
Base of limbs in the zone of polarizing activity; ant - post
18. For what reason do hypospadias need to be fixed?
Surface ectoderm
Prevent recurrent UTIs
Renal artery stenosis;
Skewed development of AP septum
19. From What embryonic layer do chromaffin cells arise?
Neural crest cells
Mesoderm
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
Surface ectoderm
20. What type of blood do umbilical veins carry? From where to where?
Endocardial cushions
Neuroectoderm
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
Oxygenated; placenta to fetus (IVC)
21. The spleen is ____________ in origin and supplied by a foregut artery
2; 1
mesodermal
3rd and 4th arches
Week 3-8
22. What secretes hCG?
Absent cerebellar vermis; cystic enlargement of 4th ventricle
Mesdoerm
Synctiotrophoblast
From teh lung;blood from IVC in RA to LA; fossa ovalis
23. What is the neural plate and From what does it form?
Endoderm
Pulm art (prox) and ductus arteriosus
3 -4 -6
Ectoderm
24. How do adults with annular pancreas present? and At What age?
20-50yrs - Abdominal pain - Postprandial fullness - Nausea - Peptic ulcers - Pancreatitis - Rarely - biliary obstruction
Nicotine; preterm labor
Neural crest cells
28 week onward
25. What arises from the fourth aortic arch?
Aortic arch (from left side); right subclavian (on the right)
Ectoderm; endoderm
Decreased separation of hemispheres across midline; cyclopia
DiGeorge
26. During what week do the limbs begin to form?
Week 4
Failure of the urachus to obliterate; outpouching of the bladder
Initial left to right shunting - then switches
Bone/cartilage and nerves
27. What teratogen can cause inhibition of intestinal folate absorption and thus neural tube defects?
Valproate acid
3rd and 4th arches
No organ in each; agenesis no primordial tissue
secondary palate
28. What surrounds the umbilical cord?
All 3
Amniotic epithelium
Temporary cervical sinus
Decidual basalis
29. What are markers for neural tube defects in the amniotic cavity? CSF?
Hepatic circulation; ligamentum venosum
Surface ectoderm
4th week
Increased AFP and acetycholinesterase (not ACh!) in CSF
30. What do the groove/clefts of the branchial apparatus correlate to?
Common carotid and internal carotid
Ectoderm
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
Neural crest cells
31. What causes a large posterior fossa in a dandy walker malformation? What is found in this fossa?
Spinothalamic first
Absent cerebellar vermis; cystic enlargement of 4th ventricle
Week 4
Mesoderm
32. What are the aspects of fetal alcohol syndrome?
Mental retardation - holoprosencephaly - facial features - fistulas
Pronephros - mesonephros - metanephros; pronephros; most cranially
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Dorsal; sensory
33. From which myotomes are muscles of the tongue derived from?
Rhombencephalon
Occiptal
Pronephros - mesonephros - metanephros; pronephros; most cranially
Mesencephalon
34. From what region does the cerebral hemisphere form?
Hypertrophy of muscularis externis of pylorus; surgical incision
Ventral; failure of urogenital folds to close
Prosencephalon
Telencephalon
35. From where is amniotic fluid produced? other than electrolytes and carbs - what else does it contain?
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
Maternally derived; meconium
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
36. What is perinauds syndrome?
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
Synctiotrophoblast
Physiologic incomplete muscular ventricular septum
Absent cerebellar vermis; cystic enlargement of 4th ventricle
37. What are the neural crest cells and where do they come form? where do they go?
Sperm plus egg
Nutrient and gas exchange
They are the edge of neural plate folding; all over the body
Allantois
38. How does annular pancreas present in children?
Surface ectoderm
Gastric outlet obstruction (bilious vomiting - feeding intolerance - abdominal distention)
Week 4; week 3
Week 2; bilaminar disk; epiblast and hypoblast
39. From what aortic arch does the stapedial artery arise? the hyoid?
secondary palate
2nd; 2nd
Oligohydramnios
External auditory meatus
40. What teratogen can cause vaginal clear cell adenocarcinoma in the fetus?
Nutrient and gas exchange
DES
Diencephalon
Lithium
41. What embryological structure gives rise to the trabeculated part of the left and right atrium?
Primitive atrium
Ventral; failure of urogenital folds to close
Allantois
can make cells
42. What do the 2nd through 4th clefts of the branchial apparatus correlate to?
Mesoderm; nucleous pulposos
Neuroectoderm
Foramen cecum and terminal sulus
Temporary cervical sinus
43. What causes a vesicourachal diverticulum? What is it?
Amniotic cavity and yolk sac
Failure of the urachus to obliterate; outpouching of the bladder
Hypospadias
Rhombencephalon
44. When does the blastocyst split into two disks? What is this disk called? What are the two germ layers called?
Ventral; failure of urogenital folds to close
Decreases
Week 2; bilaminar disk; epiblast and hypoblast
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
45. 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
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
Dorsal; sensory
46. What embryological structure gives rise to the smooth part of the right atrium?
Mesoderm
Dorsal and ventral buds
Ionizing
Right horn of the SV
47. Which is more common - epispadias or hypospadias?
Dorsal; sensory
Hypospadias
First branchial pouch
Week 8
48. What is the female remnant of processus vaginalis? male remnant?
Occiptal
Obliterated; forms tunica vaginalis
Nutrient and gas for exchange; endometrium
Indomethacin; blocks PG production
49. From What embryonic layer does the thyroid follicular cells arise?
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
Endoderm
Obliterated
Neuroectoderm
50. Cleft lip is a failure of formation of the...
Endoderm
Stapedius and hyoid artery
primary palate
Synctiotrophoblast