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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 'fetal period'- ie When is it?
From endocardial cushions (ventral and dorsal meet each other)
Membrane - all 3 from 1st appartus
Common carotid and internal carotid
Week 8
2. in hypospadias - on which side is the abnormal opening? What causes it?
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
Alkylating agents
Fetal and maternal
Ventral; failure of urogenital folds to close
3. What congenital abnormality forms a 'double bubble' on xray?
Neural crest cells
Annular pancrease
Ectoderm
Hepatic circulation; ligamentum venosum
4. From What embryonic layer is the eustachian tube from?
Week 3-8
Turners; inferior
4th arch; 6th arch
Mesoderm
5. What role does the placenta have?
Nutrient and gas exchange
Arnold chiari; syringomyelia
Urachus/median umbilical ligament; bladder and yolk sac
Neural crest cells
6. From What embryonic layer is aorticopulmonary septum from ?
Sperm plus egg
Neural crest cells
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
7. Where is sonic hedgehog gene produced? What axis is it responsible in patterning?
Neural crest cells
Neuroectoderm
They are the edge of neural plate folding; all over the body
Base of limbs in the zone of polarizing activity; ant - post
8. What is the female remnant of processus vaginalis? male remnant?
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
DiGeorge
8
Obliterated; forms tunica vaginalis
9. During what week does the heart begin to beat?
DiGeorge
Apical ectodermal ridge
Synctiotrophoblast
Week 4
10. what else is the caudal regression known as? What two teratogen can cause this in the fetus?
Allantois
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
4th/5th branchial pouches
VACTERL; OCPs and maternal diabetes
11. What is associated with only one umbilical artery?
Sonic Hedgehog
Obliterated; forms tunica vaginalis
DES
Congenital and chromosomal abnormalities
12. From What embryonic layer are the melanocytes from?
Surface ectoderm
Increase in oxygen concentration which decreases prostaglandin concentration
Urachus/median umbilical ligament; bladder and yolk sac
Neural crest cells
13. Monochorionic - ___________ twins are conjoined
monoamniotic
Dorsal ventral axis
primary palate
Neuroectoderm
14. What is the effect of teratogens before week 3?
All or none
Indomethacin; blocks PG production
Oligohydramnios
Endoderm
15. From where does the pulmonary arteries and the ductus arteriosus arise?
Week 2; bilaminar disk; epiblast and hypoblast
Maternally derived; meconium
6th aortic arch
Medial palatine processes
16. What do the groove/clefts of the branchial apparatus correlate to?
Dorsal ventral axis
During; instrinsic
Ectoderm
Epiblast
17. What is contained in the umbilical cord?
Excessive resorption of septum primum or secondum (or both)
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
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
18. What artery is derived branchial (aortic) arch 1?
Neural crest cells
Maxillary
Neural crest cells
Nutrient and gas exchange
19. what chemo drugs can cause neural tube defects in the fetus?
Folate antagonists
Initial left to right shunting - then switches
Pulm art (prox) and ductus arteriosus
monoamniotic
20. Which part of the chorionic villi can make cells?
Decidual basalis
Cytotrophoblast
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Mesoderm
21. From where does the medulla form?
Myelencephalon
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
Neural crest cells
3rd and 4th arches
22. Which branchial apparatus derivative makes the tympanic membrane of the ear?
DHT; estrogen
Bones - cartilage - and nerves
Gastric outlet obstruction (bilious vomiting - feeding intolerance - abdominal distention)
Membrane - all 3 from 1st appartus
23. What hormone is hcG structurally similar too?
...
LH
Week 4
VSD
24. Which arches form the posterior 1/3 of the tongue?
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Bulbos Cordis; right ventricle entirely
Arches 3 and 4
25. What does the first cleft/groove of the branchial apparatus develop into?
They are the edge of neural plate folding; all over the body
External auditory meatus
Bones - cartilage - and nerves
Cytotrophoblast
26. The inner layer of the chorionic villi...
Rostral fold closure ; lateral fold closure; lateral fold closure; caudal fold closure
can make cells
Polyhydramnios
Failure of bony spinal canal to fuse; no; lower vertebral levels
27. Does deformation occur during or after the embryonic period? is it due to an extrinsic or intrinsic disruption?
Urachus/median umbilical ligament; bladder and yolk sac
4th arch; 6th arch
After; extrinsic
...
28. The spinal cord is made from...
T neuroectoderm
LH
Mesoderm
...
29. What teratogen can cause an absence of digits amongst other things in the fetus? give an example.
blood entering the RA
Ectoderm
Alkylating agents
Epispadias
30. What is omphalocele? In What trisomies is it seen?
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Endoderm
is no longer intact
StyloPharyngeus
31. Which parts of the pancreas contribute to the head - uncinate process and main pancreatic duct?
Medial palatine processes
Dorsal and ventral buds
Mental retardation - holoprosencephaly - facial features - fistulas
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
32. Blood coming in the umbilical vein is ____ saturated
monoamniotic
80%
Fetal and maternal
Failure of the urachus to obliterate
33. Which is more common - epispadias or hypospadias?
Duodenum to transverse colon; distal transverse colon to rectum
Hypospadias
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Neural crest cells
34. which tracts are damaged first in syringomelia? What tract is preserved?
No organ in each; agenesis no primordial tissue
Grooves/clefts; arches; pouches
elevated AFP
Spinothalamic first
35. Septum primum (patent foramen oval) caused by excessive resorption of...
septum primum and/or secundum
VSD
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
Surface ectoderm
36. What are the clinical symptoms that present with syringomelia?
Nutrient and gas exchange
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
4th pouch
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)
37. Name a syndrome cleft palate is often seen in
DiGeorge
Temporary cervical sinus
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
1st
38. On what side is the abnormal opening in epispadias? What causes it?
3rd; proximal part of the internal carotid artery
Dorsal; faulty positioning of genital tubercle
Week 4
Polyhydramnios
39. What day is the amnion formed?
6th aortic arch
8
4th week
Thalidomide; nausea
40. The notochord is...
Neuroectoderm
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
mesoderm
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)
41. In both meningocele and myelomeningocele the dura...
is no longer intact
Neural crest cells
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
ACE inhibitors - HCTZ
42. From where does the ureteric bud arise? What does it give rise to?
Surface ectoderm
Metencephalon; cerebellum
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
43. Which part of pancreas contribute to body? tail? isthmus? accessory pancreatic duct?
3
DiGeorge
Ventral bud
Endoderm
44. What is the mnueomonic for the mesodermal defects? What does it stand for?
Urachus/median umbilical ligament; bladder and yolk sac
IX; X
Mesoderm
VACTERL- vertebral defect - anal atresia - cardiac defects - tracheo - esophageal fistula - renal defects - limb defects
45. What is perinauds syndrome?
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
Tongue
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
No more umbilical circulation emptying into RA
46. What is the female remnant of the gubernaculum? male remnant?
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
Occiptal
Mullerian inhibitory factor from Sertoli cells; increased androgen from Leydig cells
47. From What embryonic layer are the cardiovascular - lymphatics and blood from?
Indomethacin; blocks PG production
External auditory meatus
Failure of bony spinal canal to fuse; no; lower vertebral levels
Mesoderm
48. What is the neural plate and From what does it form?
LH
Upper 1/3; urogenital sinus
Fetal alcohol syndrome; mental retardation
Ectoderm
49. From What embryonic layer is the kidney and the adrenal cortex from?
3rd pouch
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
Mesoderm
...
50. From What embryonic layer do the salivary - sweat and mammary glands arise?
Surface ectoderm
Arches 3 and 4
Neural plate; closes by week 4
Mesoderm