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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 bone/cartilage and nerves are derived from branchial arch 2?
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
No organ in each; agenesis no primordial tissue
80%
Prosencephalon - mesencephalon - rhombencephalon
2. What is the female remnant of the gubernaculum? male remnant?
Week 3-8
Neuroectoderm
Ovarian ligament and round ligament of uterus; anchors testes within scrotum
Endometrium
3. When does hCG secretion take place? with what event?
Day 6; with implantation
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
Incomplete fusion of paramesonephric ducts; UT abnormalities and infertility
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
4. What do membranous interventricular septal defect cause? What does this lead to?
Initial left to right shunting - then switches
Neural crest cells
DES
VACTERL- vertebral defect - anal atresia - cardiac defects - tracheo - esophageal fistula - renal defects - limb defects
5. What do the arches of the branchial apparatus correlate to?
Mesoderm
Mesdoerm
5th
Metencephalon; cerebellum
6. _____________is common in 1st born males
Midgut; 10th week
pyloric stenosis
Bone/cartilage and nerves
Prostaglandins
7. What germ layer correlates with the branchial pouches?
Maxillary
Endoderm
All or none
Mid gut to yolk sac; omphalomesenteric duct; 7th week
8. what else is the caudal regression known as? What two teratogen can cause this in the fetus?
Week 4
Rhombencephalon
VACTERL; OCPs and maternal diabetes
is no longer intact
9. What does the foramen ovale shunt blood from - to where? What is its remnant?
From teh lung;blood from IVC in RA to LA; fossa ovalis
Maxillary
not covered
Thyroglossal duct; persists as pyramidal lobe of thyroid; foramen cecum on tongue is normal remnant of thyroglossal duct
10. What trisomy is associated with holoprosencephaly? What teratogen?
septum primum and/or secundum
elevated AFP
Hypospadias
Pataus; fetal alcohol syndrome
11. From What embryonic layer does the pineal gland arise?
Mental retardation - holoprosencephaly - facial features - fistulas
Neuroectoderm
septum primum and/or secundum
Greater horn of hyoid; CN IX (styloPharyngeus)
12. When is most important to take folic acid to prevent neural tube defects?
Ectoderm; endoderm
Surface ectoderm
1st cleft/groove (Ectoderm)
Before getting pregnant!
13. What type of - amnios does bilateral agenesis form? What three symptoms does this cause?
Oligohydramnios
Nicotine; preterm labor
Truncus arteriosus; pulmonary trunk
Mesencephalon
14. failure to close of what fold results in sternal defects? omphalocele? gastrochisis? bladder extrosphy?
Ventral shaft of penis (penile urethra); labia minora
Neural crest cells
Neuroectoderm
Rostral fold closure ; lateral fold closure; lateral fold closure; caudal fold closure
15. What is meckel's diverticulum? What is it associated with? What does that cause?
After; extrinsic
Partial closure of vitelline duct so that the patent portion is attached to ileum; ectopic gastric mucosa; melena and periumbilical pain
IX; X
Neural crest cells
16. Does malformation occur during or after the embryonic period? is it due to an extrinsic or intrinsic disruption?
Aortic arch (from left side); right subclavian (on the right)
During; instrinsic
Surface ectoderm
Neuroectoderm
17. What embryologic structure provides the aorticpulmonary septum?
Tongue
Neural crest migration - they then cause spiral
Endoderm
elevated AFP
18. What is the Eisenmeger complex?
When left to right shunting switching to right to left shunting
Primitive atrium
Day 6; with implantation
Indomethacin; blocks PG production
19. From What embryonic layer do chromaffin cells arise?
Neural crest cells
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Week 4; week 3
Decreases
20. During what week do the limbs begin to form?
Surface ectoderm
Increased AFP and acetycholinesterase (not ACh!) in CSF
Week 4
LH
21. Which branchial derivative accounts for the sensation and taste in the posterior 2/3 of the tongue? how about the very back?
Week 4
Endoderm
4th arch; 6th arch
Failure of the urachus to obliterate
22. When does the blastocyst split into two disks? What is this disk called? What are the two germ layers called?
Neural crest cells
3 -4 -6
Umbilical - midgut herniates through umbilical ring; SMA
Week 2; bilaminar disk; epiblast and hypoblast
23. What is the 'fetal period'- ie When is it?
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
Cerebral hemisphere - thalami
Week 8
Myelencephalon
24. what results if they dont? What can increase the risks of this?
Persistent connection between amniotic cavity and spinal canal; low folic acid
3rd pouch
...
Mullerian inhibitory factor from Sertoli cells; increased androgen from Leydig cells
25. What do the 2nd through 4th clefts of the branchial apparatus correlate to?
Umbilical - midgut herniates through umbilical ring; SMA
Prenatal and perinatal
Temporary cervical sinus
Folate antagonists
26. During what week does the heart begin to beat?
28 week onward
Surface ectoderm
No organ in each; agenesis no primordial tissue
Week 4
27. Where is Wnt 7 gene produced?
Surface ectoderm
Apical ectodermal ridge
mesodermal
Folate antagonists
28. From what aortic arch does the stapedial artery arise? the hyoid?
3rd; proximal part of the internal carotid artery
LH
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
2nd; 2nd
29. From what region of the brain does the aqueduct form?
4th arch; 6th arch
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
Rhombencephalon
Upper 1/3; urogenital sinus
30. Which branchial apparatus makes the external auditory meatus?
1st cleft/groove (Ectoderm)
Dorsal ventral axis
Prenatal and perinatal
Arnold Chiari and Dandy Walker; Arnold Chiari; Dandy Walker; Arnold Chiari
31. what chemo drugs can cause neural tube defects in the fetus?
Umbilical artery - vein; and whartons jelly (mucus connective tissue) - urachus
Occiptal
8
Folate antagonists
32. In anencephaly you see...
3
Base of limbs in the zone of polarizing activity; ant - post
Surface ectoderm
elevated AFP
33. To what germ layer does the branchial pouches correlate to?
Hypertrophy of muscularis externis of pylorus; surgical incision
3rd and 4th arches
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
Endoderm
34. How many umbilical arteries are there? How many umbilical veins?
Week 3; primitive streak formation from the epiblast makes the three layers
Neural crest cells
2; 1
Synctiotrophoblast; outer; no
35. What two cavities also form during the second week?
Base of limbs in the zone of polarizing activity; ant - post
Ring of pancreatic tissue can cause duodenal narrowing; ventral pancreatic bud abnormally encircles 2nd part of duodenum
Amniotic cavity and yolk sac
Dorsal; faulty positioning of genital tubercle
36. From What embryonic layer do the ANS arise?
Bulbourethral glands (of Cowper) and Prostate gland; greater vestibular glands (of Bartholin) and Urethral and paraurethral glands (of Skene)
SRY gene on Y chromosomes; sertoli and leydi; MIF and androgens; suppression of paramesonephric ducts and dev. of mesonephric (all respectively)
Endoderm
Neural crest cells
37. What effect does warfarin have on the fetus?
Allantois
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
Hemorrhage - bone deformities
DiGeorge
38. What does DHT turn the genital tubercle into? estrogen?
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
Surface ectoderm
Failure to recanalize; 21
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
39. From What embryonic layer does the inner arise?
...
Ampulla
Membrane - all 3 from 1st appartus
Primitive atrium
40. During what periods do the damages that cerebral palsy causes occur?
Tunica vaginalis not fully fused
Prenatal and perinatal
Found in lateral neck; from no obliteration of 2-4th clefts
Mesoderm
41. Which is more common - epispadias or hypospadias?
Primitive atrium
Greater horn of hyoid; CN IX (styloPharyngeus)
Neural crest cells
Hypospadias
42. What is the kidney that functions at the interim kidney in the 1st trimester? What does it later contribute to?
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
Mesonephros; male genital system
Telencephalon
Increase in oxygen concentration which decreases prostaglandin concentration
43. What does the ductus arteriosus shunt blood away from - to where? What is its remnant?
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
Dorsal; sensory
Pataus; fetal alcohol syndrome
Ectoderm
44. What teratogen can cause IUGR and ADHD in a fetus? what else can this teratogen cause?
Mental retardation - holoprosencephaly - facial features - fistulas
Vascular accident intra uterine; apple peel atresia
Nicotine; preterm labor
28 week onward
45. Where does fertilization occur?
Ampulla
Endoderm
Mesoderm; 3 week
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
46. 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)
Sperm plus egg
Failure of bony spinal canal to fuse; no; lower vertebral levels
Membrane - all 3 from 1st appartus
47. From what region do the thalami form?
IX; X
Endoderm
Diencephalon
6-30
48. From what region does the cerebral hemisphere form?
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
Ventral bud
Telencephalon
Cleft lip/palate
49. What are the clinical symptoms that present with syringomelia?
Occiptal
Neuroectoderm
Gastric outlet obstruction (bilious vomiting - feeding intolerance - abdominal distention)
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
50. From What embryonic layer does the parathyroid arise ?
Endoderm
Nutrient and gas exchange
Week 10-12; end of 1st trimester
Increase in oxygen concentration which decreases prostaglandin concentration