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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 embryological structure gives rise to the coronary sinus?
Folate antagonists
Respiratory distress syndrome
Left horn of the sinus venosus
Yolk sac; 3rd week
2. which posterior fossa malformation results in aqueductal stenosis and hydrocephaly? what other spinal cord lesion does this malformation present with?
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
Mesoderm; nucleous pulposos
A vitelline fistula - failure of vitelline duct to close
Arnold chiari; syringomyelia
3. What is meckel's diverticulum? What is it associated with? What does that cause?
Day 6; maintains corpus luteum; 1st trimester
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
Polyhydramnios
Physiologic incomplete muscular ventricular septum
4. What arises from the fourth aortic arch?
3 -4 -6
Aortic arch (from left side); right subclavian (on the right)
Maternally derived; meconium
Temporary cervical sinus
5. Which branchial apparatus makes the external auditory meatus?
Fetal alcohol syndrome; mental retardation
1st cleft/groove (Ectoderm)
T neuroectoderm
Spinothalamic first
6. From What embryonic layer is the bladder and urethra from?
Mesoderm
Ectoderm
primary palate
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
7. What artery is derived branchial (aortic) arch 6?
Pulm art (prox) and ductus arteriosus
Increase in oxygen concentration which decreases prostaglandin concentration
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
8. From where is the pancreas derived? the spleen?
is no longer intact
ACE inhibitors - HCTZ
Where the epiblast and hypoblast fuse
Foregut; dorsal mesentery (mesodermal)
9. What teratogens can cause flipper limbs (limb defects)? What is this drug used for?
Cleft lip/palate
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Endoderm
Thalidomide; nausea
10. What germ layer correlates with the branchial pouches?
Where the epiblast and hypoblast fuse
Endoderm
Surface ectoderm
From teh lung;blood from IVC in RA to LA; fossa ovalis
11. What two cavities also form during the second week?
V3; VII
T neuroectoderm
Tongue
Amniotic cavity and yolk sac
12. During what week does the heart begin to beat?
Week 4
Week 3-8
Primitive atrium
Vascular accident intra uterine; apple peel atresia
13. From What embryonic layer do the astrocytes arise?
Endoderm
Sonic Hedgehog
Ionizing
Neuroectoderm
14. What is the primitive streak? From what layer does it form?
Mesoderm; epiblast
Thyroid - cricoid - arytenoids - corniculate cuneiform
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
After; extrinsic
15. From where does pons form from? what else forms from there?
secondary palate
Metencephalon; cerebellum
Surface ectoderm
Ectoderm
16. What axis does the basal plate form? what neural system does it become?
Ventral ; motor
Surface ectoderm
Endoderm - floor of primitive pharynx
Arnold chiari; syringomyelia
17. From What embryonic layer does the parathyroid arise ?
No organ in each; agenesis no primordial tissue
Neuroectoderm
Endoderm
Thyroid - cricoid - arytenoids - corniculate cuneiform
18. What is jejunal - ileal - colonic atresia usually due to? What do you see on x ray?
Valproate acid
Mesoderm
Vascular accident intra uterine; apple peel atresia
Neural crest cells
19. What is the memranous interventricular formaen made from?
3rd pouch
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
Neural crest cells
Muscular ventricular septum; no
20. What causes the decrease in Right atrial pressure to close the fossa ovale?
8
Alkylating agents
Dorsal; sensory
No more umbilical circulation emptying into RA
21. what drug is used to help close a PDA? what else does this drug treat?
Post. sup wall; luteal phase
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
3rd; proximal part of the internal carotid artery
Indomethacin; blocks PG production
22. What is the physiological herniation that occurs at the 6th week - what herniates out of the umbilical ring? when it comes back in the 10th week - What does it rotate around?
2nd; 2nd
8
Amniotic epithelium
Umbilical - midgut herniates through umbilical ring; SMA
23. From What embryonic layer are the dorsal root and celiac ganglion from?
4th pouch
Neural crest cells
Temporary cervical sinus
Mesoderm
24. what happens in hydrocele?
Mesoderm
Foramen cecum and terminal sulus
80%
Tunica vaginalis not fully fused
25. what closes the ductus arteriousus?
1st branchial arch
Week 4; week 3
Increase in oxygen concentration which decreases prostaglandin concentration
Cytotrophoblast and synctiotrophoblast
26. At what week does the fetus look like a baby?
Prenatal and perinatal
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
Neuroectoderm
Week 8
27. From what branchial derivative do the parafollicular cells arise?
Polyhydramnios
3 -4 -6
4th/5th branchial pouches
Bones - cartilage - and nerves
28. Cleft palate is a failure of formation of the...
secondary palate
Week 8
Ventral ; motor
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
29. From What embryonic layer do the ANS arise?
Mesencephalon
SRY gene on Y chromosomes; sertoli and leydi; MIF and androgens; suppression of paramesonephric ducts and dev. of mesonephric (all respectively)
Neural crest cells
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
30. What teratogen can cause an absence of digits amongst other things in the fetus? give an example.
Greater horn of hyoid; CN IX (styloPharyngeus)
Ventral shaft of penis (penile urethra); labia minora
Muscles and arteries
Alkylating agents
31. Which cranial nerve innervates the motor function of the tongue?
Tunica vaginalis not fully fused
Primitive atrium
Germinal matrix hemorrhage
XII
32. in hypospadias - on which side is the abnormal opening? What causes it?
Deoxygenated blood; fetal internal iliac arteries to placenta
1st
Alkylating agents
Ventral; failure of urogenital folds to close
33. What role does the placenta have?
Stapedius and hyoid artery
Nutrient and gas exchange
Amniotic cavity and yolk sac
Absent cerebellar vermis; cystic enlargement of 4th ventricle
34. Most myelomeningoceles present in the _______ region
lumbosacral
Pataus; fetal alcohol syndrome
Muscular ventricular septum; no
Branchial arch 2
35. What causes urine discharge from the umbilicus?
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
Midgut; 10th week
Failure of the urachus to obliterate
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
36. Which branchial apparatus develops into the inferior parathyroids?
3rd pouch
lumbosacral
Mesoderm
Right horn of the SV
37. What is used to keep the PDA open?
Maxillary and medial nasal processes
Allantois
Prostaglandins
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
38. From where do the three different kidneys come from? Which is the earliest one? is it located most cranially or caudally?
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
Pronephros - mesonephros - metanephros; pronephros; most cranially
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
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)
39. Where does the blastocyst implant in the uterus? During what phase of the menstrual cycle?
Post. sup wall; luteal phase
Diencephalon
1st
Valproate acid
40. From where does the ureteric bud arise? What does it give rise to?
Pulm art (prox) and ductus arteriosus
Hypospadias
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
Medial palatine processes
41. From where is amniotic fluid produced? other than electrolytes and carbs - what else does it contain?
Maternally derived; meconium
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
Sperm plus egg
Mesdoerm
42. From what region of the brain does the lateral ventricles and the 3rd ventricle form?
Synctiotrophoblast
5th
Prosencephalon
Mesoderm
43. what bone/cartilage and nerves are derived from branchial arch 3?
Fetal and maternal
3rd pouch
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
Greater horn of hyoid; CN IX (styloPharyngeus)
44. From What embryonic layer does connective tissue and muscle arise?
Mesoderm
Female; paramesonephric; mesonephric
hypertrophy
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
45. Which branchial derivative creates the middle ear cavity - eustachian tube and mastoid air cells?
Midgut; 10th week
First branchial pouch
Endocardial cushions
IMA
46. what structures are the derivatives of the neural crest cells in branchial arches?
Neural crest cells
Thickened ectoderm at end of each developing limb
Maternally derived; meconium
Bone/cartilage and nerves
47. what junction is the last to canalize? what implications does this have down the line?
Surface ectoderm
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
Ventral bud
Fetal and maternal
48. From What embryonic layer does the thyroid follicular cells arise?
Fallopian tube - uterus - upper 1/3 of vagina
ACE inhibitors - HCTZ
Nicotine; preterm labor
Endoderm
49. What is an example of a syndrome that can cause abnormal neural crest migration and thus CV abnormalities?
6th aortic arch
Lithium
DiGeorge
Week 3; primitive streak formation from the epiblast makes the three layers
50. From What embryonic layer do the salivary - sweat and mammary glands arise?
Surface ectoderm
During; instrinsic
Ventral shaft of penis (penile urethra); labia minora
Dorsal; sensory