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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 causes the transposition of the great vessels? What does it result in?
Decreased separation of hemispheres across midline; cyclopia
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
External auditory meatus
Urachus/median umbilical ligament; bladder and yolk sac
2. 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?
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
Surface ectoderm
Before getting pregnant!
Endoderm - floor of primitive pharynx
3. Which branchial derivative accounts for taste in the ant 2/3?
Neuroectoderm
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
Branchial arch 2
IX; X
4. Where is the mothers blood located in the placenta?
Mesoderm
Lacunae in between the chorionic villi
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
...
5. Cleft palate is a failure of fusion of the lateral palatine processes - the nasal septum and or the ________?
Medial palatine processes
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
Neural crest cells
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
6. What is the female remnant of the gubernaculum? male remnant?
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
Surface ectoderm
Epiblast
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
7. What can vit A in excess cause in the fetus?
Yolk sac; 3rd week
3rd pouch
Lots - cleft palate/lip
Aortic arch (from left side); right subclavian (on the right)
8. What is duodenal atresia usually due to? What trisomy is it most often seen in?
Failure to recanalize; 21
Endoderm
Neural crest cells
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
9. From where do the three different kidneys come from? Which is the earliest one? is it located most cranially or caudally?
Lithium
Pronephros - mesonephros - metanephros; pronephros; most cranially
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
Mesdoerm
10. From What embryonic layer does the parathyroid arise ?
VACTERL; OCPs and maternal diabetes
Endoderm
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
arnold chiari associated with thoraclumbar myelomeningocele
11. From What embryonic lare are the odontoblasts from?
During; instrinsic
Oligohydramnios
Neural crest cells
Surface ectoderm
12. what muscles are derived from branchial arch 1?
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
Fluid filled cavity in spinal cord; C8- T1; arnold chiari II
Upper 1/3; urogenital sinus
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
13. Which branchial apparatus develops into the inferior parathyroids?
3rd pouch
Endoderm
Base of limbs in the zone of polarizing activity; ant - post
Nutrient and gas for exchange; endometrium
14. what closes the ductus arteriousus?
Neural crest cells
Increase in oxygen concentration which decreases prostaglandin concentration
Duodenum to transverse colon; distal transverse colon to rectum
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
15. From What embryonic layer does the neurohypophysis arise?
Week 10-12; end of 1st trimester
Neuroectoderm
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
16. WithIn what week does gastrulation occur? What is gastrulation?
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
Week 3; primitive streak formation from the epiblast makes the three layers
Mesoderm; nucleous pulposos
Hypertrophy of muscularis externis of pylorus; surgical incision
17. What is congenital pharyngocutaneous fistula? and How does it occur?
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
Before getting pregnant!
28 week onward
Sonic Hedgehog
18. _____________is common in 1st born males
Muscles and arteries
pyloric stenosis
1st cleft/groove (Ectoderm)
All 3
19. Before birth - blood entering the LA is less than...
Neuroectoderm
can make cells
Hemorrhage - bone deformities
blood entering the RA
20. What is the Eisenmeger complex?
Prosencephalon
When left to right shunting switching to right to left shunting
Neural crest migration - they then cause spiral
Tunica vaginalis not fully fused
21. The spleen is ____________ in origin and supplied by a foregut artery
Rhombencephalon
Occiptal
mesodermal
2; 1
22. What is the primitive streak? From what layer does it form?
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
mesoderm
Mesoderm; epiblast
Mesoderm
23. How do you differentiate a thyroglossal duct cyst from a persistent cervical sinus?
Neural crest cells
1st cleft/groove (Ectoderm)
Amniotic epithelium
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
24. What are the two walls of the prosencephalon and What do they become?
Neural crest cells
Ebsteins anomaly; tricuspid atresia
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
Cerebral hemisphere - thalami
25. What is the kidney that functions at the interim kidney in the 1st trimester? What does it later contribute to?
Primitive atrium
Mesonephros; male genital system
A vitelline fistula - failure of vitelline duct to close
Mental retardation - holoprosencephaly - facial features - fistulas
26. What components do the mesoderm of the branchial arches give rise to?
Physiologic incomplete muscular ventricular septum
Muscles and arteries
Absent cerebellar vermis; cystic enlargement of 4th ventricle
not covered
27. What is an example of a syndrome that can cause abnormal neural crest migration and thus CV abnormalities?
Bones - cartilage - and nerves
DiGeorge
Allantois
ACE inhibitors - HCTZ
28. When is most important to take folic acid to prevent neural tube defects?
Before getting pregnant!
Week 3-8
Neural crest cells
Neuroectoderm
29. Which branchial derivative accounts for the posterior 2/3 of the tongue?
Telencephalon
Membrane - all 3 from 1st appartus
3rd and 4th arches
Common carotid and internal carotid
30. Pyloric stenosis is characterized by _____________ of muscularis externis in the sphincter
hypertrophy
2; 1
Decreased pulmonary resistance in the pulmonary vasculature
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
31. what bone/cartilage and nerves are derived from branchial arch 3?
Greater horn of hyoid; CN IX (styloPharyngeus)
...
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
Prosencephalon - mesencephalon - rhombencephalon
32. In anencephaly you see...
Lots - cleft palate/lip
LH
elevated AFP
can make cells
33. Where is the apical ectodermal ridge?
Synctiotrophoblast
Allantois
Thickened ectoderm at end of each developing limb
Hypospadias
34. What causes tetralogy of Fallot?
Base of limbs in the zone of polarizing activity; ant - post
Skewed development of AP septum
Prostaglandins
Tetracyclines
35. What is perinauds syndrome?
Hepatic circulation; ligamentum venosum
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
Obliterated
Day 6; with implantation
36. With the first breath the infant take - pulmonary vasculature resistance _______ which causes an increase in left atrial pressure
Decreases
Cranio - caudal; segmental
Hemorrhage - bone deformities
Ectoderm
37. What do the groove/clefts of the branchial apparatus correlate to?
Endoderm
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
Spinothalamic first
Ectoderm
38. what closes the interventricular foramen?
From endocardial cushions (ventral and dorsal meet each other)
Physiologic incomplete muscular ventricular septum
3rd pouch
Obliterated
39. which teratogen can cause Ebsteins anomaly in the fetus?
Neuroectoderm
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
Lithium
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
40. What layer is the epiblast? hypoblast?
Oxygenated; placenta to fetus (IVC)
Ectoderm; endoderm
Neuroectoderm
Surface ectoderm
41. From What embryonic layer is the vagina from? testes? ovaries?
Neural crest cells
V3; VII
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Mesoderm
42. What is the effect of teratogens before week 3?
Common carotid and internal carotid
Oxygenated; placenta to fetus (IVC)
All or none
Neuroectoderm
43. From What embryonic layer does the inner arise?
...
Decreases
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Failure of bony spinal canal to fuse; no; lower vertebral levels
44. What does the vitelline duct connect? What is it also known as? when should it obliterate?
Mid gut to yolk sac; omphalomesenteric duct; 7th week
Mesoderm
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Oligohydramnios
45. What is the prochordal plate?
Surface ectoderm
Telencephalon
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
Where the epiblast and hypoblast fuse
46. What are the two components of the placenta? From What do they form? which one secreted hcG?
...
Indomethacin; blocks PG production
Decreased pulmonary resistance in the pulmonary vasculature
Endometrium
47. What teratogens can cause flipper limbs (limb defects)? What is this drug used for?
Thalidomide; nausea
Where the epiblast and hypoblast fuse
Neuroectoderm
Ectoderm
48. From what region does the cerebral hemisphere form?
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
Decreased separation of hemispheres across midline; cyclopia
Telencephalon
Dorsal; faulty positioning of genital tubercle
49. What arises from the fourth aortic arch?
Aortic arch (from left side); right subclavian (on the right)
They are the edge of neural plate folding; all over the body
No organ in each; agenesis no primordial tissue
Sonic Hedgehog
50. From What embryonic layer does bone of the skulls arise?
Mesoderm
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
Neural crest cells
V3; VII