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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. When does hcG get secreted? What does it do?up until when ?
Day 6; maintains corpus luteum; 1st trimester
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
Surface ectoderm
Midgut; 10th week
2. What are the three regions of the brain (in order of cranial to caudal)?
Cranio - caudal; segmental
Prosencephalon - mesencephalon - rhombencephalon
Duodenum to transverse colon; distal transverse colon to rectum
Thalidomide; nausea
3. Which branchial derivative accounts for the sensation and taste in the posterior 2/3 of the tongue? how about the very back?
4th arch; 6th arch
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
Neural crest cells
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
4. which posterior fossa malformation results in aqueductal stenosis and hydrocephaly? what other spinal cord lesion does this malformation present with?
Arnold chiari; syringomyelia
Neural crest cells
Obliterated; forms tunica vaginalis
Decreases
5. What is the notochord? What does the notochord later become?
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
Dorsal; sensory
Neuroectoderm
Mesoderm; nucleous pulposos
6. For what reason do hypospadias need to be fixed?
Prevent recurrent UTIs
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
Transposition of great vessels (failure to spiral)- right to left shunt; tetralogy of Fallout (right to left shunt caused by skewed development of septum); persistent TA (partial septum development - also right to left shunt)
Bones - cartilage - and nerves
7. Does deformation occur during or after the embryonic period? is it due to an extrinsic or intrinsic disruption?
is no longer intact
Muscular ventricular septum; no
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
After; extrinsic
8. Which part of pancreas contribute to body? tail? isthmus? accessory pancreatic duct?
Ventral bud
Dorsal and ventral buds
Ebsteins anomaly; tricuspid atresia
Week 4; week 3
9. what closes the interventricular foramen?
Branchial arch 2
Physiologic incomplete muscular ventricular septum
Dorsal; faulty positioning of genital tubercle
Respiratory distress syndrome
10. What results in annular pancreas? How does it happen?
VSD
Increase in oxygen concentration which decreases prostaglandin concentration
can make cells
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
11. What is associated with only one umbilical artery?
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
Dorsal ventral axis
Congenital and chromosomal abnormalities
Amniotic epithelium
12. The notochord is...
Neural crest cells
mesoderm
StyloPharyngeus
Lithium
13. What is the most common subtype of tracheoesophageal fistula? name some symptoms (hint: O2 levels - feeding - stomach on CXR - - amnios? - NG tube? - respiratory infection? )
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
2nd pouch
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
Umbilical - midgut herniates through umbilical ring; SMA
14. what week do the genitalia start to have male/female characteristics? What trimester is that?
Fluid filled cavity in spinal cord; C8- T1; arnold chiari II
Week 10-12; end of 1st trimester
Endoderm
Primitive ventricle
15. What are the two walls of the prosencephalon and What do they become?
Cerebral hemisphere - thalami
Germinal matrix hemorrhage
3rd pouch
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
16. What does the midgut form? hindgut?
Duodenum to transverse colon; distal transverse colon to rectum
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
Week 8
Nutrient and gas for exchange; endometrium
17. When does the blastocyst split into two disks? What is this disk called? What are the two germ layers called?
Fluid filled syrinx causes expansion and degeneration of cord tracts
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
Week 8
Week 2; bilaminar disk; epiblast and hypoblast
18. What hormones are in charge of external genitalia development in the fetus? (in both male and female)
DHT; estrogen
Neuroectoderm
Week 8
Alkylating agents
19. Cleft palate is a failure of fusion of the lateral palatine processes - the nasal septum and or the ________?
Turners; inferior
1st branchial arch
Failure of bony spinal canal to fuse; no; lower vertebral levels
Medial palatine processes
20. what closes the ductus arteriousus?
Increase in oxygen concentration which decreases prostaglandin concentration
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
Obliterated
External auditory meatus
21. What day is the amnion formed?
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
28 week onward
8
Diencephalon
22. From What embryonic layer does the skin dermis arise?
Mesoderm
blood entering the RA
Dorsal ventral axis
DiGeorge
23. Which arches form the posterior 1/3 of the tongue?
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
From endocardial cushions (ventral and dorsal meet each other)
Arches 3 and 4
Neural crest cells
24. From what region do the thalami form?
Tunica vaginalis not fully fused
Cleft lip/palate
Diencephalon
Female; paramesonephric; mesonephric
25. what structures are the derivatives of the neural crest cells in branchial arches?
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Pharynx to duodenum; duodenum to transverse colon; distal transverse colon to rectum
Bone/cartilage and nerves
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
26. What hormone is hcG structurally similar too?
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
LH
Neuroectoderm
Primitive ventricle
27. What does DHT turn the labioscrotal swelling into? estrogen?
Duodenum to transverse colon; distal transverse colon to rectum
Neuroectoderm
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
Scrotum; labia majora
28. From what does bicornuate uterus arise? What is it associated with?
Germinal matrix hemorrhage
Primitive atrium
Incomplete fusion of paramesonephric ducts; UT abnormalities and infertility
Thalidomide; nausea
29. From what aortic arch does the common carotid artery arise? what else arises from this arch?
3rd; proximal part of the internal carotid artery
Nutrient and gas exchange
2nd pouch
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
30. From What embryonic layer does the lens of the eye arise?
Surface ectoderm
Primitive ventricle
Endoderm - floor of primitive pharynx
Diencephalon
31. From What embryonic layer does the gut tube epithelium arise?
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
Amniotic cavity and yolk sac
Ventral shaft of penis (penile urethra); labia minora
Endoderm
32. Septum primum (patent foramen oval) caused by excessive resorption of...
septum primum and/or secundum
ACE inhibitors - HCTZ
Prosencephalon - mesencephalon - rhombencephalon
Tongue
33. What does the first branchial pouch create?
IMA
Pulm art (prox) and ductus arteriosus
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
34. From What embryonic layer is the eustachian tube from?
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
Mesoderm
Endocardial cushions
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
35. What happens in pancreas divisum? what results?
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Yolk sac; 3rd week
Surface ectoderm
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
36. What artery is derived branchial (aortic) arch 6?
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Pulm art (prox) and ductus arteriosus
Muscles and arteries
Week 4
37. What causes persistent Truncus Arteriosus? What does it result in?
When left to right shunting switching to right to left shunting
Neuroectoderm
Fetal alcohol syndrome; mental retardation
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
38. What teratogen can cause IUGR and ADHD in a fetus? what else can this teratogen cause?
Rostral fold closure ; lateral fold closure; lateral fold closure; caudal fold closure
Folate antagonists
Nicotine; preterm labor
Mesencephalon
39. What do the groove/clefts of the branchial apparatus correlate to?
Ectoderm
Midgut; 10th week
Mesoderm; 3 week
Foregut; dorsal mesentery (mesodermal)
40. From What embryonic layer are the melanocytes from?
Dorsal; sensory
Increased AFP and acetycholinesterase (not ACh!) in CSF
Neural crest cells
Allantois
41. What day is the chorion formed?
Mesoderm
3
Physiologic incomplete muscular ventricular septum
Before getting pregnant!
42. 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
4th pouch
Spinothalamic first
Outgrowth of mesonephric as ureteric bud; most caudal
43. What embryonic structure gives rise to the ascending aorta? what else does it give rise to?
Mesoderm
Truncus arteriosus; pulmonary trunk
Week 4; week 3
Physiologic incomplete muscular ventricular septum
44. From What embryonic layer does the epidermis arise?
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
Oligohydramnios
septum primum and/or secundum
Surface ectoderm
45. Which branchial apparatus develops into the inferior parathyroids?
Tunica vaginalis not fully fused
3rd pouch
Post. sup wall; luteal phase
Mesoderm
46. What axis does the basal plate form? what neural system does it become?
Physiologic incomplete muscular ventricular septum
Synctiotrophoblast
Ventral ; motor
hypospadias
47. From where is amniotic fluid produced? other than electrolytes and carbs - what else does it contain?
Muscular ventricular septum; no
Maternally derived; meconium
Amniotic cavity and yolk sac
Prosencephalon
48. What is the effect of teratogens after week 8?
Deformation
lumbosacral
Hypertrophy of muscularis externis of pylorus; surgical incision
Metencephalon; cerebellum
49. what separates the atria from the ventricles?
Endocardial cushions
Endoderm
Transposition of great vessels (failure to spiral)- right to left shunt; tetralogy of Fallout (right to left shunt caused by skewed development of septum); persistent TA (partial septum development - also right to left shunt)
Dorsal and ventral buds
50. What three layers form during gastrulation? From What do they form? and what week does gastrulation occur?
blood entering the RA
Decreased separation of hemispheres across midline; cyclopia
Endoderm - floor of primitive pharynx
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3