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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 difference between agenesis and aplasia?
Umbilical - midgut herniates through umbilical ring; SMA
monoamniotic
Endoderm
No organ in each; agenesis no primordial tissue
2. What is the leading cause of birth defects in the US? what else is this perpetrator the leading cause of?
Surface ectoderm
Synctiotrophoblast; outer; no
Fetal alcohol syndrome; mental retardation
Week 8
3. Which cranial nerve innervates the motor function of the tongue?
Ventral bud
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Neuroectoderm
XII
4. What causes urine discharge from the umbilicus?
septum primum and/or secundum
1st cleft/groove (Ectoderm)
Failure of the urachus to obliterate
Bulbos Cordis; right ventricle entirely
5. What is associated with only one umbilical artery?
DiGeorge
VACTERL- vertebral defect - anal atresia - cardiac defects - tracheo - esophageal fistula - renal defects - limb defects
4th/5th branchial pouches
Congenital and chromosomal abnormalities
6. What type of blood do umbilical veins carry? From where to where?
Skewed development of AP septum
Oxygenated; placenta to fetus (IVC)
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
Sperm plus egg
7. what structures are the derivatives of the neural crest cells in branchial arches?
Bone/cartilage and nerves
IX; X
Decreased separation of hemispheres across midline; cyclopia
Foregut; dorsal mesentery (mesodermal)
8. From what region do the thalami form?
Physiologic incomplete muscular ventricular septum
SRY gene on Y chromosomes; sertoli and leydi; MIF and androgens; suppression of paramesonephric ducts and dev. of mesonephric (all respectively)
Ventral shaft of penis (penile urethra); labia minora
Diencephalon
9. ______________ is associated with ventral curvature of the penis
hypospadias
3rd and 4th arches
Outgrowth of mesonephric as ureteric bud; most caudal
External auditory meatus
10. What are the two components of the fetal component of the placenta?
Mesoderm
Cytotrophoblast and synctiotrophoblast
elevated AFP
Mesoderm
11. What axis does the basal plate form? what neural system does it become?
Arches 3 and 4
Endoderm
Ventral ; motor
Fetal alcohol syndrome; mental retardation
12. What axis is Wnt 7 responsible for developing?
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
Fluid filled syrinx causes expansion and degeneration of cord tracts
Physiologic incomplete muscular ventricular septum
Dorsal ventral axis
13. What secretes hCG?
Dorsal; sensory
Foregut; dorsal mesentery (mesodermal)
External auditory meatus
Synctiotrophoblast
14. what closes the interventricular foramen?
No more umbilical circulation emptying into RA
Physiologic incomplete muscular ventricular septum
Gastric outlet obstruction (bilious vomiting - feeding intolerance - abdominal distention)
Maternally derived; meconium
15. What are the aspects of fetal alcohol syndrome?
Incomplete; yes
secondary palate
Endocardial cushions
Mental retardation - holoprosencephaly - facial features - fistulas
16. What gene is produced in the zone of polarizing activity?
Before getting pregnant!
Sonic Hedgehog
Fluid filled syrinx causes expansion and degeneration of cord tracts
Week 2; bilaminar disk; epiblast and hypoblast
17. Which branchial derivative creates the middle ear cavity - eustachian tube and mastoid air cells?
Neural crest cells
Muscles and arteries
First branchial pouch
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
18. Name two endocardial cushion defects.
Ebsteins anomaly; tricuspid atresia
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
DiGeorge
Week 10-12; end of 1st trimester
19. What is congenital pharyngocutaneous fistula? and How does it occur?
3rd and 4th arches
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
can make cells
From endocardial cushions (ventral and dorsal meet each other)
20. Which CN accounts for the anterior 2/3 of the tongues sensation and pain? how about taste?
V3; VII
Respiratory distress syndrome
Umbilical - midgut herniates through umbilical ring; SMA
Ebsteins anomaly; tricuspid atresia
21. Most myelomeningoceles present in the _______ region
lumbosacral
Mesoderm
Left horn of the sinus venosus
Epiblast
22. What are the three regions of the brain (in order of cranial to caudal)?
Arches 3 and 4
monoamniotic
Prosencephalon - mesencephalon - rhombencephalon
Obliterated
23. What is the Eisenmeger complex?
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
When left to right shunting switching to right to left shunting
Valproate acid
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
24. What does DHT turn the labioscrotal swelling into? estrogen?
Fallopian tube - uterus - upper 1/3 of vagina
Mesoderm
Week 8
Scrotum; labia majora
25. Gastroschisis is extrusion of abdominal contents out of abdominal folds ___________ by peritoneum
not covered
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
pyloric stenosis
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
26. What does the RET gene encode? what neoplasias is it associated with?
Decidual basalis
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
From teh lung;blood from IVC in RA to LA; fossa ovalis
Bulbos Cordis; right ventricle entirely
27. What is a zygote?
Sperm plus egg
Nicotine; preterm labor
Thickened ectoderm at end of each developing limb
From teh lung;blood from IVC in RA to LA; fossa ovalis
28. How do AV canals form?
hypospadias
Thalidomide; nausea
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
From endocardial cushions (ventral and dorsal meet each other)
29. What is the neural plate and From what does it form?
Ectoderm
Week 4; week 3
Neural crest cells
2; 1
30. What teratogen can cause an absence of digits amongst other things in the fetus? give an example.
Synctiotrophoblast
Alkylating agents
Neural crest cells
Foregut; dorsal mesentery (mesodermal)
31. From where does the prostate develop? seminal vesicles? fallopian tube? lower 2/3 of the vagina? ejaculatory duct? epididymis? uterus? upper 1/3 of the vagina?
Week 2; bilaminar disk; epiblast and hypoblast
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
is no longer intact
32. When does erythropoeisis begin in the bone marow?
28 week onward
Neural plate; closes by week 4
Rhombencephalon
Week 8
33. From which germlayer does the thyroid develop?? From what structure exactly?
Endoderm - floor of primitive pharynx
Greater horn of hyoid; CN IX (styloPharyngeus)
Apical ectodermal ridge
Amniotic cavity and yolk sac
34. What is holoprosencephaly? what eye disorder does it result in?
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
Decreased separation of hemispheres across midline; cyclopia
Neural plate; closes by week 4
pyloric stenosis
35. The inner layer of the chorionic villi...
can make cells
Mesdoerm
Surface ectoderm
Failure of bony spinal canal to fuse; no; lower vertebral levels
36. What causes the increase in left atrial pressure to close the fossa ovale?
Dorsal; sensory
Neural crest cells
Decreased pulmonary resistance in the pulmonary vasculature
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
37. From What embryonic layer is the bladder and urethra from?
Mesoderm
From endocardial cushions (ventral and dorsal meet each other)
SRY gene on Y chromosomes; sertoli and leydi; MIF and androgens; suppression of paramesonephric ducts and dev. of mesonephric (all respectively)
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
38. Monochorionic - ___________ twins are conjoined
Oxygenated; placenta to fetus (IVC)
monoamniotic
Neural crest cells
Bones - cartilage - and nerves
39. Which branchial derivative accounts for the sensation and taste in the posterior 2/3 of the tongue? how about the very back?
1st cleft/groove (Ectoderm)
Common carotid and internal carotid
Primitive ventricle
4th arch; 6th arch
40. In both meningocele and myelomeningocele the dura...
Pataus; fetal alcohol syndrome
is no longer intact
From teh lung;blood from IVC in RA to LA; fossa ovalis
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
41. What role does the placenta have?
Primitive ventricle
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
Nutrient and gas exchange
Cytotrophoblast and synctiotrophoblast
42. What causes the degeneration of the spinal cord in syringomelia?
8
4th pouch
Mesoderm
Fluid filled syrinx causes expansion and degeneration of cord tracts
43. What three layers form during gastrulation? From What do they form? and what week does gastrulation occur?
Mesdoerm
Failure of the urachus to obliterate
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3
Mesoderm
44. For what reason do hypospadias need to be fixed?
Prevent recurrent UTIs
Rhombencephalon
Hypospadias
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
45. What causes meconium discharge from the umbilicus?
Fetal and maternal
Pronephros - mesonephros - metanephros; pronephros; most cranially
Aortic arch and prox part of subclavian
A vitelline fistula - failure of vitelline duct to close
46. What components do the mesoderm of the branchial arches give rise to?
elevated AFP
Polyhydramnios
Muscles and arteries
secondary palate
47. From which branchial derivative does the anterior 2/3 of the tongue develop?
pyloric stenosis
Week 8
mesoderm
1st branchial arch
48. What artery is derived branchial (aortic) arch 6?
Decidual basalis
Pulm art (prox) and ductus arteriosus
Ectoderm; endoderm
When left to right shunting switching to right to left shunting
49. What is the effect of teratogens after week 8?
Ventral; failure of urogenital folds to close
Failure to recanalize; 21
Neuroectoderm
Deformation
50. What artery is derived branchial (aortic) arch 2?
Synctiotrophoblast
Stapedius and hyoid artery
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
28 week onward