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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. Where is erythropoeisis in the weeks 3-8 of fetal development? Where does it occur after that? until when?
IMA
Yolk sac; 3rd week
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
...
2. From What embryonic layer are the pia and arachnoid from?
Neural crest cells
Neuroectoderm
Bone/cartilage and nerves
Membrane - all 3 from 1st appartus
3. What do membranous interventricular septal defect cause? What does this lead to?
They are the edge of neural plate folding; all over the body
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
3rd; proximal part of the internal carotid artery
Initial left to right shunting - then switches
4. Name a syndrome cleft palate is often seen in
DiGeorge
Surface ectoderm
Aortic arch and prox part of subclavian
2nd pouch
5. Which CN accounts for the anterior 2/3 of the tongues sensation and pain? how about taste?
XII
External auditory meatus
V3; VII
5th
6. Where does the blastocyst implant in the uterus? During what phase of the menstrual cycle?
Post. sup wall; luteal phase
Rhombencephalon
Mesonephros; male genital system
Ionizing
7. From where is the allantois formed? During what week?
Decreased separation of hemispheres across midline; cyclopia
Yolk sac; 3rd week
primary palate
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
8. What type of blood do umbilical arteries carry? From where to where?
Failure of the urachus to obliterate; outpouching of the bladder
They are the edge of neural plate folding; all over the body
Deoxygenated blood; fetal internal iliac arteries to placenta
Bone/cartilage and nerves
9. What is the initial step to interventricular septum development? is it complete?
Turners; inferior
Surface ectoderm
Muscular ventricular septum; no
All or none
10. What is the effect of teratogens before week 3?
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
All or none
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Sonic Hedgehog
11. What weeks are considered the 'embryonic period'?
Excessive resorption of septum primum or secondum (or both)
Week 3-8
Midgut; 10th week
hypospadias
12. When does hcG get secreted? What does it do?up until when ?
arnold chiari associated with thoraclumbar myelomeningocele
Day 6; maintains corpus luteum; 1st trimester
Endoderm
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
13. Where is the mothers blood located in the placenta?
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
Lacunae in between the chorionic villi
Hypertrophy of muscularis externis of pylorus; surgical incision
Dorsal; sensory
14. What embryological structures give rise to the SVC?
Right common cardinal vein and right anterior cardinal vein
Surface ectoderm
ACE inhibitors - HCTZ
Dorsal and ventral buds
15. What are two common findings in pyloric stenosis?
Week 4
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
All or none
can make cells
16. From what germ layer does the primitive heart tube arise?
Tunica vaginalis not fully fused
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
Mesoderm
Metencephalon; cerebellum
17. What causes the degeneration of the spinal cord in syringomelia?
Dorsal and ventral buds
Primitive ventricle
Fluid filled syrinx causes expansion and degeneration of cord tracts
Endoderm - floor of primitive pharynx
18. In both meningocele and myelomeningocele the dura...
is no longer intact
Metencephalon; cerebellum
After; extrinsic
Temporary cervical sinus
19. When does erythropoeisis begin in the bone marow?
Maternally derived; meconium
4th week
28 week onward
1st
20. in hypospadias - on which side is the abnormal opening? What causes it?
Pharynx to duodenum; duodenum to transverse colon; distal transverse colon to rectum
Ventral; failure of urogenital folds to close
Neural crest cells
Dorsal; faulty positioning of genital tubercle
21. When does organogenesis occur?
Left horn of the sinus venosus
Mesoderm
Week 3-8
Embryonic period; 1st trimester
22. From What embryonic layer do the salivary - sweat and mammary glands arise?
Medial palatine processes
Where the epiblast and hypoblast fuse
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
Surface ectoderm
23. What axis does the basal plate form? what neural system does it become?
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
Week 10-12; end of 1st trimester
Ventral ; motor
24. From What embryonic layer does the retina arise?
Lots - cleft palate/lip
Neuroectoderm
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
Incomplete; yes
25. What is duodenal atresia usually due to? What trisomy is it most often seen in?
Sperm plus egg
Surface ectoderm
mesoderm
Failure to recanalize; 21
26. 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
Found in lateral neck; from no obliteration of 2-4th clefts
Neuroectoderm
is no longer intact
27. What is the female remnant of processus vaginalis? male remnant?
Pronephros - mesonephros - metanephros; pronephros; most cranially
Obliterated; forms tunica vaginalis
Decreased separation of hemispheres across midline; cyclopia
3rd and 4th arches
28. What is the homeobox gene responsible in developing? (What axis)
Failure of the urachus to obliterate; outpouching of the bladder
Cranio - caudal; segmental
V3; VII
Allantois
29. What causes a vesicourachal diverticulum? What is it?
28 week onward
Bones - cartilage - and nerves
Failure of the urachus to obliterate; outpouching of the bladder
lumbosacral
30. What is holoprosencephaly? what eye disorder does it result in?
Decreased separation of hemispheres across midline; cyclopia
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
31. From What embryonic layer does the epithelial linings of the oral cavity arise?
Surface ectoderm
Endoderm
XII
VSD
32. Cleft lip is a failure of fusion of ________ and ______.
Oligohydramnios
Maxillary and medial nasal processes
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
Prostaglandins
33. What two things cause VACTERL syndrome?
Mid gut to yolk sac; omphalomesenteric duct; 7th week
Deformation
Pulm art (prox) and ductus arteriosus
OCPS and maternal diabetes
34. what muscles are derived from branchial arch 1?
Synctiotrophoblast; outer; no
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
Mesoderm
Primitive atrium
35. From what region does the cerebral hemisphere form?
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
Telencephalon
Decreases
Prostaglandins
36. What artery is derived branchial (aortic) arch 3?
Neuroectoderm
Common carotid and internal carotid
is no longer intact
No organ in each; agenesis no primordial tissue
37. From What embryonic layer does the brain arise?
Neuroectoderm
Rhombencephalon
Aortic arch (from left side); right subclavian (on the right)
Dorsal ventral axis
38. When does hCG secretion take place? with what event?
Dorsal; faulty positioning of genital tubercle
Week 10-12; end of 1st trimester
Day 6; with implantation
Ectoderm
39. What is an arnold chiari II malformation? through what hole does it herniate?
Cerebellar tonsillar herniation through foramen magnum
IMA
StyloPharyngeus
XII
40. From What embryonic layer do the astrocytes arise?
DES
Day 6; with implantation
Neuroectoderm
Deformation
41. What is the primitive streak? From what layer does it form?
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
Duodenum to transverse colon; distal transverse colon to rectum
Mesoderm; epiblast
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
42. During what months is the fetus most susceptible to teratogens? What trimester?
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
can make cells
Embryonic period; 1st trimester
After; extrinsic
43. what bone/cartilage and nerves are derived from branchial arch 3?
Diencephalon
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Greater horn of hyoid; CN IX (styloPharyngeus)
Allantois
44. What trisomy is associated with holoprosencephaly? What teratogen?
Pataus; fetal alcohol syndrome
Neural crest cells
Ampulla
Prevent recurrent UTIs
45. Only _______________________________ are associated with neural tube defects
arnold chiari associated with thoraclumbar myelomeningocele
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
All 3
Diencephalon
46. How do you differentiate a thyroglossal duct cyst from a persistent cervical sinus?
Ebsteins anomaly; tricuspid atresia
Pataus; fetal alcohol syndrome
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
Prostaglandins
47. Which branchial apparatus develops into the thymus?
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
3rd pouch
Persistent connection between amniotic cavity and spinal canal; low folic acid
Mesoderm
48. Which branchial arch derivative is obliterated?
Fluid filled cavity in spinal cord; C8- T1; arnold chiari II
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
5th
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
49. What hormone is hcG structurally similar too?
Hepatic circulation; ligamentum venosum
LH
Rhombencephalon
Ebsteins anomaly; tricuspid atresia
50. Which branchial derivative accounts for the posterior 2/3 of the tongue?
3rd and 4th arches
Outgrowth of mesonephric as ureteric bud; most caudal
5th
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)