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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 is the effect of teratogens before week 3?
Tunica vaginalis not fully fused
5th
All or none
Scrotum; labia majora
2. What type of radiation is teratogenic ?
Mesoderm
Ionizing
Found in lateral neck; from no obliteration of 2-4th clefts
No more umbilical circulation emptying into RA
3. From What embryonic lare are the odontoblasts from?
Neural crest cells
Congenital and chromosomal abnormalities
Pharynx to duodenum; duodenum to transverse colon; distal transverse colon to rectum
DiGeorge
4. What does the ductus venosus shunt blood away from? What is its remnant?
Sonic Hedgehog
Upper 1/3; urogenital sinus
From teh lung;blood from IVC in RA to LA; fossa ovalis
Hepatic circulation; ligamentum venosum
5. What embryologic structure gives rise to the smooth outflow tracts of the ventricles? what else does it give rise to?
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Bulbos Cordis; right ventricle entirely
secondary palate
Before getting pregnant!
6. On what side is the abnormal opening in epispadias? What causes it?
Female; paramesonephric; mesonephric
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
Dorsal; faulty positioning of genital tubercle
mesodermal
7. How do you differentiate a thyroglossal duct cyst from a persistent cervical sinus?
Thyroglossal duct cysts will move with swallowing while persistent cervical sinuses in lateral neck wont
Endocardial cushions
Week 4
Failure of the urachus to obliterate
8. From where does the ureteric bud arise? What does it give rise to?
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
Rhombencephalon
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
Temporary cervical sinus
9. What produces testis determining factor? what cells are produced from this? and What do they secrete? does this result in?
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
Greater horn of hyoid; CN IX (styloPharyngeus)
8
SRY gene on Y chromosomes; sertoli and leydi; MIF and androgens; suppression of paramesonephric ducts and dev. of mesonephric (all respectively)
10. Where is erythropoeisis in the weeks 3-8 of fetal development? Where does it occur after that? until when?
Yolk sac; liver (weeks 6-30) and spleen (9-28 weeks)
Found in lateral neck; from no obliteration of 2-4th clefts
septum primum and/or secundum
Increase in oxygen concentration which decreases prostaglandin concentration
11. Cleft palate is a failure of formation of the...
elevated AFP
4th/5th branchial pouches
secondary palate
Neuroectoderm
12. From What embryonic layer do the salivary - sweat and mammary glands arise?
Maxillary and medial nasal processes
Surface ectoderm
Oxygenated; placenta to fetus (IVC)
Foregut; dorsal mesentery (mesodermal)
13. Which branchial derivative accounts for the posterior 2/3 of the tongue?
3rd and 4th arches
Failure of the urachus to obliterate; outpouching of the bladder
Aortic arch (from left side); right subclavian (on the right)
Week 3-8
14. From what region of the brain does the lateral ventricles and the 3rd ventricle form?
Fallopian tube - uterus - upper 1/3 of vagina
Persistance of herniation of abdominal contents into umbilical cord covered by peritoneum; 13 - 18
Prosencephalon
Ventral bud
15. Which parts of the pancreas contribute to the head - uncinate process and main pancreatic duct?
ACE inhibitors - HCTZ
Mesoderm
Dorsal and ventral buds
Hemorrhage - bone deformities
16. How do adults with annular pancreas present? and At What age?
Week 2; bilaminar disk; epiblast and hypoblast
1st cleft/groove (Ectoderm)
Mid gut to yolk sac; omphalomesenteric duct; 7th week
20-50yrs - Abdominal pain - Postprandial fullness - Nausea - Peptic ulcers - Pancreatitis - Rarely - biliary obstruction
17. Most myelomeningoceles present in the _______ region
Primitive ventricle
StyloPharyngeus
Mid gut to yolk sac; omphalomesenteric duct; 7th week
lumbosacral
18. What is the defect in spina bifida occulta? is there any structural herniation? where on the spinal cord is it usually seen?
Week 8
Neural plate; closes by week 4
Failure of bony spinal canal to fuse; no; lower vertebral levels
Common carotid and internal carotid
19. What teratogens can cause discolored teeth?
Week 4
Tetracyclines
Neuroectoderm
Endoderm
20. Where does fertilization occur?
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
Maxillary
Ampulla
Epiblast
21. From where is the pancreas derived? the spleen?
Neuroectoderm
Foregut; dorsal mesentery (mesodermal)
XII
hypertrophy
22. What type of - amnios does bilateral agenesis form? What three symptoms does this cause?
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
septum primum and/or secundum
Endoderm
Oligohydramnios
23. in hypospadias - on which side is the abnormal opening? What causes it?
DiGeorge
Ventral; failure of urogenital folds to close
T neuroectoderm
From endocardial cushions (ventral and dorsal meet each other)
24. What is holoprosencephaly? what eye disorder does it result in?
2; 1
Decreased separation of hemispheres across midline; cyclopia
All or none
IX; X
25. What embryologic structure provides the aorticpulmonary septum?
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
1st arch neural crest fails to migrate --> mandibular hypoplasia - facial abnormalities (cleft palate - decreased slanting of palpebral fissures)
Neural crest migration - they then cause spiral
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
26. Which branchial apparatus develops into the inferior parathyroids?
is no longer intact
3rd pouch
Nutrient and gas for exchange; endometrium
Cranio - caudal; segmental
27. What hormones are in charge of external genitalia development in the fetus? (in both male and female)
Surface ectoderm
DHT; estrogen
VACTERL; OCPs and maternal diabetes
4th pouch
28. what invaginates to form the primitive streak?
Mesonephros; male genital system
IMA
Epiblast
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
29. What is germinal matrix hemorrhage associated with?
Respiratory distress syndrome
Primitive ventricle
hypertrophy
Fetal alcohol syndrome; mental retardation
30. From What embryonic layer are the dorsal root and celiac ganglion from?
Week 3-8
VACTERL; OCPs and maternal diabetes
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
Neural crest cells
31. With the first breath the infant take - pulmonary vasculature resistance _______ which causes an increase in left atrial pressure
Decreases
Bones - cartilage - and nerves
Pataus; fetal alcohol syndrome
Yolk sac; 3rd week
32. What two cavities also form during the second week?
Amniotic cavity and yolk sac
Oligohydramnios
Foregut; dorsal mesentery (mesodermal)
ACE inhibitors - HCTZ
33. What do the arches of the branchial apparatus correlate to?
Branchial arch 2
Week 8
Mesdoerm
Cerebral hemisphere - thalami
34. From what aortic arch does the first part of the maxillary artery arise?
Ectoderm
1st
2nd; 2nd
28 week onward
35. From What embryonic layer do chromaffin cells arise?
Neural crest cells
Indomethacin; blocks PG production
Endometrium
Day 6; with implantation
36. which teratogen can cause Ebsteins anomaly in the fetus?
Neural plate; closes by week 4
Neural crest cells
Thalidomide; nausea
Lithium
37. What type of blood do umbilical arteries carry? From where to where?
Mesoderm
Deoxygenated blood; fetal internal iliac arteries to placenta
VSD
Decreased separation of hemispheres across midline; cyclopia
38. Where is sonic hedgehog gene produced? What axis is it responsible in patterning?
Base of limbs in the zone of polarizing activity; ant - post
Fetal alcohol syndrome; mental retardation
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)
Muscles and arteries
39. what else is the caudal regression known as? What two teratogen can cause this in the fetus?
VACTERL; OCPs and maternal diabetes
Indomethacin; blocks PG production
Dorsal; sensory
DHT; estrogen
40. From What embryonic layer does the retina arise?
Maxillary and medial nasal processes
Neuroectoderm
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
Physiologic incomplete muscular ventricular septum
41. When does the notochord form? and When does the neural plate form?
Mesoderm; 3 week
Branchial arch 2
blood entering the RA
Day 6; with implantation
42. what results if they dont? What can increase the risks of this?
Ionizing
blood entering the RA
Neuroectoderm
Persistent connection between amniotic cavity and spinal canal; low folic acid
43. Septum primum (patent foramen oval) caused by excessive resorption of...
Neural crest cells
septum primum and/or secundum
Telencephalon
5th
44. What causes urine discharge from the umbilicus?
Vascular accident intra uterine; apple peel atresia
Week 3; primitive streak formation from the epiblast makes the three layers
Failure of the urachus to obliterate
Hemorrhage - bone deformities
45. What is perinauds syndrome?
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
Cerebellar tonsillar herniation through foramen magnum
Week 3-8
Epispadias
46. What is associated with only one umbilical artery?
Spinothalamic first
Congenital and chromosomal abnormalities
Mesoderm
Mesoderm; epiblast
47. When does the blastocyst split into two disks? What is this disk called? What are the two germ layers called?
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
80%
Week 2; bilaminar disk; epiblast and hypoblast
Mullerian inhibitory factor from Sertoli cells; increased androgen from Leydig cells
48. what bone/cartilage and nerves are derived from branchial arch 3?
Apical ectodermal ridge; limb lengthening; stimulates mitosis of underlying mesoderm
ACE inhibitors - HCTZ
Decreases
Greater horn of hyoid; CN IX (styloPharyngeus)
49. From what arches are the neural crest cells that form the aorticpulmonary septum derived?
A vitelline fistula - failure of vitelline duct to close
Occiptal
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
3 -4 -6
50. What type of blood do umbilical veins carry? From where to where?
Endoderm - floor of primitive pharynx
Aortic arch and prox part of subclavian
Spinothalamic first
Oxygenated; placenta to fetus (IVC)