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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 a vesicourachal diverticulum? What is it?
1st
Aortic arch and prox part of subclavian
Endoderm - floor of primitive pharynx
Failure of the urachus to obliterate; outpouching of the bladder
2. From What embryonic lare are the odontoblasts from?
Nutrient and gas exchange
Neural crest cells
Ventral bud
Duodenum to transverse colon; distal transverse colon to rectum
3. From What embryonic layer do the salivary - sweat and mammary glands arise?
Surface ectoderm
Hepatic circulation; ligamentum venosum
A vitelline fistula - failure of vitelline duct to close
2nd pouch
4. What weeks are considered the 'embryonic period'?
Post. sup wall; luteal phase
Hemorrhage - bone deformities
Week 3-8
Neural plate; closes by week 4
5. what junction is the last to canalize? what implications does this have down the line?
Persistent connection between amniotic cavity and spinal canal; low folic acid
IMA
Pataus; fetal alcohol syndrome
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
6. What is the female remnant of the gubernaculum? male remnant?
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
Arches 3 and 4
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
7. What is holoprosencephaly? what eye disorder does it result in?
IMA
Found in lateral neck; from no obliteration of 2-4th clefts
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
Decreased separation of hemispheres across midline; cyclopia
8. What is hypoplasia? is primordial tissue present?
Incomplete; yes
Midgut; 10th week
can make cells
Endoderm
9. what muscles are derived from branchial arch 3?
Primitive ventricle
StyloPharyngeus
Neural crest migration - they then cause spiral
Ebsteins anomaly; tricuspid atresia
10. What teratogen can cause vaginal clear cell adenocarcinoma in the fetus?
Surface ectoderm
DES
Failure to recanalize; 21
Fluid filled syrinx causes expansion and degeneration of cord tracts
11. What are the three regions of the brain (in order of cranial to caudal)?
Decreased pulmonary resistance in the pulmonary vasculature
Neuroectoderm
Prosencephalon - mesencephalon - rhombencephalon
Endoderm
12. What does the midgut form? hindgut?
3rd; proximal part of the internal carotid artery
pyloric stenosis
Duodenum to transverse colon; distal transverse colon to rectum
Incomplete; yes
13. What embryonic structure gives rise to the ascending aorta? what else does it give rise to?
Umbilical - midgut herniates through umbilical ring; SMA
Week 8
Scrotum; labia majora
Truncus arteriosus; pulmonary trunk
14. Monochorionic - ___________ twins are conjoined
2nd pouch
Ectoderm
monoamniotic
Amniotic cavity and yolk sac
15. How is amniontic fluid excreted? How is amniotic fluid resorped?
Surface ectoderm
Neuroectoderm
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
Surface ectoderm
16. From where is the pancreas derived? the spleen?
Week 2; bilaminar disk; epiblast and hypoblast
Ventral; failure of urogenital folds to close
Foregut; dorsal mesentery (mesodermal)
Mesoderm
17. Where is the decidua basalis derived from?
Dorsal; sensory
Endometrium
Common carotid and internal carotid
Dorsal ventral axis
18. During what months is the fetus most susceptible to teratogens? What trimester?
Respiratory distress syndrome
Embryonic period; 1st trimester
Deoxygenated blood; fetal internal iliac arteries to placenta
Aortic arch and prox part of subclavian
19. From What embryonic layer does the thyroid follicular cells arise?
Fluid filled cavity in spinal cord; C8- T1; arnold chiari II
Week 3-8
Endoderm
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3
20. From What embryonic layer does the pineal gland arise?
lumbosacral
Sperm plus egg
arnold chiari associated with thoraclumbar myelomeningocele
Neuroectoderm
21. From where is amniotic fluid produced? other than electrolytes and carbs - what else does it contain?
Maternally derived; meconium
Epiblast
DiGeorge
Mental retardation - holoprosencephaly - facial features - fistulas
22. Which branchial arch derivative is obliterated?
5th
Primitive atrium
Surface ectoderm
Surface ectoderm
23. How do adults with annular pancreas present? and At What age?
Cleft lip/palate
Pharynx to duodenum; duodenum to transverse colon; distal transverse colon to rectum
20-50yrs - Abdominal pain - Postprandial fullness - Nausea - Peptic ulcers - Pancreatitis - Rarely - biliary obstruction
Amniotic cavity and yolk sac
24. From where does the permanent kidney for? is it most caudal or most cranial?
Outgrowth of mesonephric as ureteric bud; most caudal
monoamniotic
Persistent connection between amniotic cavity and spinal canal; low folic acid
Foramen cecum and terminal sulus
25. From what does bicornuate uterus arise? What is it associated with?
Incomplete fusion of paramesonephric ducts; UT abnormalities and infertility
Right common cardinal vein and right anterior cardinal vein
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
Week 4
26. From where does the pulmonary arteries and the ductus arteriosus arise?
Dorsal; faulty positioning of genital tubercle
Neural crest cells
6th aortic arch
T neuroectoderm
27. Does deformation occur during or after the embryonic period? is it due to an extrinsic or intrinsic disruption?
Obliterated
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
After; extrinsic
Oligohydramnios
28. What does the mullerian duct develop into? wollffian?
Thickened ectoderm at end of each developing limb
Tetracyclines
6-30
Fallopian tube - uterus - upper 1/3 of vagina
29. Which branchial derivative creates the epithelial lining of the palatine tonsils?
Lacunae in between the chorionic villi
6-30
4th pouch
2nd pouch
30. What embryologic structure gives rise to the smooth outflow tracts of the ventricles? what else does it give rise to?
Bulbos Cordis; right ventricle entirely
Surface ectoderm
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
31. What is meckel's diverticulum? What is it associated with? What does that cause?
Ampulla
Cranio - caudal; segmental
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
When left to right shunting switching to right to left shunting
32. Where does the blastocyst implant in the uterus? During what phase of the menstrual cycle?
Post. sup wall; luteal phase
Gastric outlet obstruction (bilious vomiting - feeding intolerance - abdominal distention)
Embryonic period; 1st trimester
Physiologic incomplete muscular ventricular septum
33. What hormones are in charge of external genitalia development in the fetus? (in both male and female)
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Neural crest cells
Temporary cervical sinus
DHT; estrogen
34. During what periods do the damages that cerebral palsy causes occur?
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
Week 8
All or none
Prenatal and perinatal
35. From What embryonic layer do the ependymal cells arise?
Duodenum to transverse colon; distal transverse colon to rectum
T neuroectoderm
Neuroectoderm
Occiptal
36. From What embryonic layer does the sensory organs of the ear arise?
V3; VII
80%
They are the edge of neural plate folding; all over the body
Surface ectoderm
37. What does the ductus arteriosus shunt blood away from - to where? What is its remnant?
Neuroectoderm
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
External auditory meatus
38. What components do the mesoderm of the branchial arches give rise to?
Muscles and arteries
Physiologic incomplete muscular ventricular septum
Surface ectoderm
Ventral ; motor
39. From where did a branchial cleft cyst arise if it found?
Amniotic cavity and yolk sac
Found in lateral neck; from no obliteration of 2-4th clefts
Ectoderm
Neural crest cells
40. What causes a patent foramen ovale?
3 -4 -6
2; 1
DiGeorge
Excessive resorption of septum primum or secondum (or both)
41. From where do the three different kidneys come from? Which is the earliest one? is it located most cranially or caudally?
Muscles and arteries
Cytotrophoblast and synctiotrophoblast
Alkylating agents
Pronephros - mesonephros - metanephros; pronephros; most cranially
42. How many umbilical arteries are there? How many umbilical veins?
Neural crest cells
Mesoderm
2; 1
Aortic arch and prox part of subclavian
43. Where is the FGF gene produced? What is it responsible for - How does it do this?
Diencephalon
Endocardial cushions
Primitive atrium
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
44. From What embryonic layer does the parathyroid arise ?
Nicotine; preterm labor
Endoderm
Lacunae in between the chorionic villi
Germinal matrix hemorrhage
45. which genital embryology is default? From what duct? what duct degenerates without signal to stay?
Surface ectoderm
Neural crest cells
is no longer intact
Female; paramesonephric; mesonephric
46. What embryological structure gives rise to the coronary sinus?
Neuroectoderm
Left horn of the sinus venosus
IX; X
Ebsteins anomaly; tricuspid atresia
47. What do membranous interventricular septal defect cause? What does this lead to?
Mesoderm; epiblast
Initial left to right shunting - then switches
lumbosacral
Thyroid - cricoid - arytenoids - corniculate cuneiform
48. what else is the caudal regression known as? What two teratogen can cause this in the fetus?
VACTERL; OCPs and maternal diabetes
4th pouch
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
Surface ectoderm
49. What is the homeobox gene responsible in developing? (What axis)
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
Cranio - caudal; segmental
V3; VII
Week 4
50. What axis is Wnt 7 responsible for developing?
Dorsal ventral axis
Renal artery stenosis;
Temporary cervical sinus
2nd; 2nd