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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 tetralogy of Fallot?
Skewed development of AP septum
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
Neuroectoderm
2. What causes the obstruction in pyloric stenosis? treatment?
6th aortic arch
Ampulla
Increase in oxygen concentration which decreases prostaglandin concentration
Hypertrophy of muscularis externis of pylorus; surgical incision
3. From What embryonic layer does the brain arise?
Neuroectoderm
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3
Prostaglandins
4. Name a syndrome cleft palate is often seen in
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
Mental retardation - holoprosencephaly - facial features - fistulas
DiGeorge
From teh lung;blood from IVC in RA to LA; fossa ovalis
5. 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?
Mesoderm
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
No organ in each; agenesis no primordial tissue
6. What do the groove/clefts of the branchial apparatus correlate to?
They are the edge of neural plate folding; all over the body
Oxygenated; placenta to fetus (IVC)
Prosencephalon
Ectoderm
7. During what week does the heart begin to beat?
2; 1
...
Week 4
hypospadias
8. What weeks are considered the 'embryonic period'?
Epispadias
Week 3-8
Week 8
External auditory meatus
9. What is the kidney that functions at the interim kidney in the 1st trimester? What does it later contribute to?
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
Tetracyclines
Neural crest cells
Mesonephros; male genital system
10. What produces testis determining factor? what cells are produced from this? and What do they secrete? does this result in?
SRY gene on Y chromosomes; sertoli and leydi; MIF and androgens; suppression of paramesonephric ducts and dev. of mesonephric (all respectively)
Epiblast
...
Ionizing
11. What role does the placenta have?
Nutrient and gas exchange
Endocardial cushions
When the AP septum meets and fuses with the muscular ventricular septum to form membranous intraventricular septum - closing interventricular foramen
Mesoderm
12. What surrounds the umbilical cord?
Amniotic epithelium
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
lumbosacral
Ventral ; motor
13. From where does the signal come from to suppress paramesonephric ducts? what stimulates development of the mesonephric ducts?
They are the edge of neural plate folding; all over the body
Mid gut to yolk sac; omphalomesenteric duct; 7th week
4th arch; 6th arch
Mullerian inhibitory factor from Sertoli cells; increased androgen from Leydig cells
14. what bone/cartilage and nerves are derived from branchial arch 1?
Synctiotrophoblast; outer; no
Obliterated
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
...
15. What are the aspects of fetal alcohol syndrome?
Mental retardation - holoprosencephaly - facial features - fistulas
Week 8
Maxillary and medial nasal processes
3 -4 -6
16. What is the neural plate and From what does it form?
Ectoderm
blood entering the RA
3rd and 4th arches
Pulm art (prox) and ductus arteriosus
17. What causes the increase in left atrial pressure to close the fossa ovale?
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
Decreased pulmonary resistance in the pulmonary vasculature
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
18. What causes meconium discharge from the umbilicus?
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
Mid gut to yolk sac; omphalomesenteric duct; 7th week
A vitelline fistula - failure of vitelline duct to close
19. From what aortic arch does the common carotid artery arise? what else arises from this arch?
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
Fluid filled syrinx causes expansion and degeneration of cord tracts
3rd; proximal part of the internal carotid artery
Week 4
20. Where is sonic hedgehog gene produced? What axis is it responsible in patterning?
Base of limbs in the zone of polarizing activity; ant - post
Neuroectoderm
Neural crest cells
Oxygenated; placenta to fetus (IVC)
21. What is the notochord? What does the notochord later become?
V3; VII
Mesoderm; nucleous pulposos
Skewed development of AP septum
Cerebellar tonsillar herniation through foramen magnum
22. From What embryonic layer does the epidermis arise?
Surface ectoderm
All 3
Ventral shaft of penis (penile urethra); labia minora
DiGeorge
23. What does DHT turn the labioscrotal swelling into? estrogen?
Scrotum; labia majora
Neuroectoderm
80%
1st branchial arch
24. In anencephaly you see...
Neuroectoderm
Epispadias
elevated AFP
Mid gut to yolk sac; omphalomesenteric duct; 7th week
25. Which branchial derivative accounts for the posterior 2/3 of the tongue?
Congenital and chromosomal abnormalities
3rd and 4th arches
blood entering the RA
Mesoderm
26. What happens in pancreas divisum? what results?
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Ectoderm
Persistent connection between amniotic cavity and spinal canal; low folic acid
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
27. Where is Wnt 7 gene produced?
Increased AFP and acetycholinesterase (not ACh!) in CSF
Common carotid and internal carotid
Apical ectodermal ridge
1st
28. What part of the vagina does the mullerian duct form? Where does the rest come from?
Temporary cervical sinus
Upper 1/3; urogenital sinus
Cytotrophoblast
Hemorrhage - bone deformities
29. From What embryonic layer are the melanocytes from?
DiGeorge
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
Midgut; 10th week
Neural crest cells
30. What is the fate of the cervical sinuses that develop from the 2nd -4th branchial grooves?
Mesoderm
Obliterated
Prosencephalon
1st branchial arch
31. Which CN allows for taste and sensation in the posterior 1/3 of the tongue? how about the very back ?
Right horn of the SV
Neuroectoderm
hypospadias
IX; X
32. What are markers for neural tube defects in the amniotic cavity? CSF?
Increased AFP and acetycholinesterase (not ACh!) in CSF
From endocardial cushions (ventral and dorsal meet each other)
Week 3-8
Cleft lip/palate
33. In order to survive tricuspid atresia - What do you need?
Apical ectodermal ridge
VSD
Surface ectoderm
From endocardial cushions (ventral and dorsal meet each other)
34. What is the difference between agenesis and aplasia?
From teh lung;blood from IVC in RA to LA; fossa ovalis
Tunica vaginalis not fully fused
No organ in each; agenesis no primordial tissue
Day 6; with implantation
35. Blood coming in the umbilical vein is ____ saturated
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
80%
Nicotine; preterm labor
is no longer intact
36. What type of - amnios does bilateral agenesis form? What three symptoms does this cause?
Oligohydramnios
XII
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
Scrotum; labia majora
37. Where is the most common ectopic thyroid tissue?
Tongue
lumbosacral
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
38. Where is the FGF gene produced? What is it responsible for - How does it do this?
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
hypertrophy
Lots - cleft palate/lip
Maternally derived; meconium
39. The inner layer of the chorionic villi...
Week 3-8
Foregut; dorsal mesentery (mesodermal)
hypospadias
can make cells
40. From what region of the brain does the aqueduct form?
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
Rhombencephalon
DiGeorge
Endoderm
41. What does DHT turn the urogenital folds into? estrogen?
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
Hepatic circulation; ligamentum venosum
Ventral shaft of penis (penile urethra); labia minora
They are the edge of neural plate folding; all over the body
42. When does hcG get secreted? What does it do?up until when ?
Day 6; maintains corpus luteum; 1st trimester
lumbosacral
Mesdoerm
Week 4
43. what muscles are derived from branchial arch 3?
Hepatic circulation; ligamentum venosum
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
StyloPharyngeus
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
44. From which myotomes are muscles of the tongue derived from?
Prosencephalon
Occiptal
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
Endoderm
45. From What embryonic layer does bone arise ?
4th pouch
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
Mesoderm
Indomethacin; blocks PG production
46. When does organogenesis occur?
Week 3-8
V3; VII
Increase in oxygen concentration which decreases prostaglandin concentration
Metencephalon; cerebellum
47. What teratogens can cause CN VIII toxicity in the fetus?
Aminoglycosides
is no longer intact
Cranio - caudal; segmental
OCPS and maternal diabetes
48. From What embryonic layer does the skin dermis arise?
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
Mesoderm
Thickened ectoderm at end of each developing limb
49. What embryologic structure gives rise to the smooth outflow tracts of the ventricles? what else does it give rise to?
OCPS and maternal diabetes
Dorsal ventral axis
Bulbos Cordis; right ventricle entirely
Cytotrophoblast and synctiotrophoblast
50. _____________is common in 1st born males
Rostral fold closure ; lateral fold closure; lateral fold closure; caudal fold closure
pyloric stenosis
Prostaglandins
Cerebral hemisphere - thalami