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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. When does hcG get secreted? What does it do?up until when ?
Day 6; maintains corpus luteum; 1st trimester
Nutrient and gas exchange
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
mesoderm
2. What does the RET gene encode? what neoplasias is it associated with?
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
Stapedius and hyoid artery
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
4th week
3. What teratogens can cause discolored teeth?
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
Spinothalamic first
Tetracyclines
Pronephros - mesonephros - metanephros; pronephros; most cranially
4. Does malformation occur during or after the embryonic period? is it due to an extrinsic or intrinsic disruption?
During; instrinsic
Endoderm
First branchial pouch
Mesoderm
5. From What embryonic layer is the spleen from?
Mesoderm
Epispadias
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
Respiratory distress syndrome
6. What teratogen can cause vaginal clear cell adenocarcinoma in the fetus?
DES
Bones - cartilage - and nerves
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
Mesencephalon
7. From What embryonic layer do the astrocytes arise?
Mullerian inhibitory factor from Sertoli cells; increased androgen from Leydig cells
Surface ectoderm
Neuroectoderm
Neural plate; closes by week 4
8. What causes the increase in left atrial pressure to close the fossa ovale?
Ebsteins anomaly; tricuspid atresia
Rhombencephalon
Gastric outlet obstruction (bilious vomiting - feeding intolerance - abdominal distention)
Decreased pulmonary resistance in the pulmonary vasculature
9. From what region does the cerebral hemisphere form?
Telencephalon
Maternally derived; meconium
Mesoderm
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
10. What results in annular pancreas? How does it happen?
Aminoglycosides
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
Sperm plus egg
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
11. Weeks _______ erythropoiesis takes place in the liver
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
6-30
Mesencephalon
Lithium
12. From What embryonic layer is the bladder and urethra from?
not covered
Mesoderm
Week 2; bilaminar disk; epiblast and hypoblast
Yolk sac; 3rd week
13. From What embryonic layer does a craniopharygioma arise?
Stapedius and hyoid artery
Oligohydramnios
Neuroectoderm
Surface ectoderm
14. What two cavities also form during the second week?
Cytotrophoblast
Amniotic cavity and yolk sac
Failure to recanalize; 21
Prenatal and perinatal
15. From What embryonic layer does the oligodendrocytes arise?
Neuroectoderm
Duodenum to transverse colon; distal transverse colon to rectum
Epiblast
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
16. What causes urine discharge from the umbilicus?
Primitive atrium
Failure of the urachus to obliterate
mesoderm
Muscles and arteries
17. From what region of the brain does the lateral ventricles and the 3rd ventricle form?
Surface ectoderm
Failure of the urachus to obliterate; outpouching of the bladder
First branchial pouch
Prosencephalon
18. What weeks are considered the 'embryonic period'?
Surface ectoderm
Fetal alcohol syndrome; mental retardation
Skewed development of AP septum
Week 3-8
19. What part of the gut rotates around the SMA? and At what point?
Midgut; 10th week
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
20. What is annular pancreas associated with in infants?
Initial left to right shunting - then switches
Aortic arch (from left side); right subclavian (on the right)
Decreases
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
21. 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
Neuroectoderm
Surface ectoderm
IX; X
22. What teratogen can cause IUGR and ADHD in a fetus? what else can this teratogen cause?
Decreases
Nicotine; preterm labor
Week 3; primitive streak formation from the epiblast makes the three layers
pyloric stenosis
23. What embryological structure gives rise to the coronary sinus?
Surface ectoderm
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
Left horn of the sinus venosus
Gastric outlet obstruction (bilious vomiting - feeding intolerance - abdominal distention)
24. 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?
LH
Arnold Chiari and Dandy Walker; Arnold Chiari; Dandy Walker; Arnold Chiari
Endometrium
Cerebral hemisphere - thalami
25. When does the notochord form? and When does the neural plate form?
Mesencephalon
Mesoderm; 3 week
Polyhydramnios
Dorsal; sensory
26. what muscles are derived from branchial arch 6? CN?
4th pouch
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
Ionizing
Decidual basalis
27. From where does the permanent kidney for? is it most caudal or most cranial?
Outgrowth of mesonephric as ureteric bud; most caudal
Thyroid - cricoid - arytenoids - corniculate cuneiform
Upper 1/3; urogenital sinus
1st cleft/groove (Ectoderm)
28. What are the two walls of the prosencephalon and What do they become?
Neural crest cells
2nd pouch
Mesoderm
Cerebral hemisphere - thalami
29. What embryologic structure gives rise to the smooth outflow tracts of the ventricles? what else does it give rise to?
1st branchial arch
Initial left to right shunting - then switches
Surface ectoderm
Bulbos Cordis; right ventricle entirely
30. How many components are there to the placenta? What are they called?
Lots - cleft palate/lip
Fetal and maternal
Epispadias
Neural crest cells
31. From What embryonic layer does the adenohypophysis arise?
Surface ectoderm
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
20-50yrs - Abdominal pain - Postprandial fullness - Nausea - Peptic ulcers - Pancreatitis - Rarely - biliary obstruction
mesoderm
32. The spleen is ____________ in origin and supplied by a foregut artery
Pataus; fetal alcohol syndrome
mesodermal
Wolffian; mullerian
Neural crest cells
33. which tracts are damaged first in syringomelia? What tract is preserved?
Spinothalamic first
Skewed development of AP septum
Metencephalon; cerebellum
4th/5th branchial pouches
34. in hypospadias - on which side is the abnormal opening? What causes it?
Obliterated; forms tunica vaginalis
Ventral; failure of urogenital folds to close
Decreased pulmonary resistance in the pulmonary vasculature
Neuroectoderm
35. What is DiGeorge syndrome and What does it result in?
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
SRY gene on Y chromosomes; sertoli and leydi; MIF and androgens; suppression of paramesonephric ducts and dev. of mesonephric (all respectively)
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
elevated AFP
36. What hormone is hcG structurally similar too?
LH
Surface ectoderm
pyloric stenosis
Rhombencephalon
37. During what week does the heart begin to beat?
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
Week 4
Mesoderm; 3 week
Prosencephalon - mesencephalon - rhombencephalon
38. When does the neural tube form and From what does it form?
Neural plate; closes by week 4
Arnold chiari; syringomyelia
Mesoderm
Urachus/median umbilical ligament; bladder and yolk sac
39. From what aortic arch does the stapedial artery arise? the hyoid?
2nd; 2nd
not covered
Neuroectoderm
All or none
40. What type of - amnios does bilateral agenesis form? What three symptoms does this cause?
Mesoderm
Oligohydramnios
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
IX; X
41. What embryological structure gives rise to the trabeculated parts of the left and right ventricle?
Aminoglycosides
secondary palate
Mesoderm; nucleous pulposos
Primitive ventricle
42. What is the female remnant of processus vaginalis? male remnant?
Neuroectoderm
Ebsteins anomaly; tricuspid atresia
Mental retardation - holoprosencephaly - facial features - fistulas
Obliterated; forms tunica vaginalis
43. what muscles are derived from branchial arch 1?
Ionizing
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
Thickened ectoderm at end of each developing limb
Amniotic epithelium
44. what chemo drugs can cause neural tube defects in the fetus?
Synctiotrophoblast
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Polyhydramnios
Folate antagonists
45. From what are the umbilical arteries and veins derived from?
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
Allantois
Pronephros - mesonephros - metanephros; pronephros; most cranially
Endoderm - floor of primitive pharynx
46. What does DHT turn the urogenital folds into? estrogen?
Prosencephalon
VACTERL; OCPs and maternal diabetes
Day 6; with implantation
Ventral shaft of penis (penile urethra); labia minora
47. What part of the vagina does the mullerian duct form? Where does the rest come from?
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
Upper 1/3; urogenital sinus
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
hypertrophy
48. From What embryonic layer is aorticopulmonary septum from ?
Hemorrhage - bone deformities
Rhombencephalon
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
Neural crest cells
49. Which CN allows for taste and sensation in the posterior 1/3 of the tongue? how about the very back ?
LH
Ectoderm
IX; X
3 -4 -6
50. Septum primum (patent foramen oval) caused by excessive resorption of...
Excessive resorption of septum primum or secondum (or both)
Sonic Hedgehog
septum primum and/or secundum
External auditory meatus