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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. Which CN allows for taste and sensation in the posterior 1/3 of the tongue? how about the very back ?
Hypospadias
Mesdoerm
IX; X
A vitelline fistula - failure of vitelline duct to close
2. Where is the mothers blood located in the placenta?
Foramen cecum and terminal sulus
Cerebellar tonsillar herniation through foramen magnum
They are the edge of neural plate folding; all over the body
Lacunae in between the chorionic villi
3. From What embryonic layer do the parafollicular cells of the thyroid arise?
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
Cleft lip/palate
Neural crest cells
Fetal and maternal
4. From which germlayer does the thyroid develop?? From what structure exactly?
Decidual basalis
Deformation
All 3
Endoderm - floor of primitive pharynx
5. In what chromosomal disorder is horseshoe kidney commonly seen? what poles of the kidneys fuse?
Arches 3 and 4
Week 10-12; end of 1st trimester
Turners; inferior
Obliterated; forms tunica vaginalis
6. in hypospadias - on which side is the abnormal opening? What causes it?
80%
Neural crest cells
Ventral; failure of urogenital folds to close
3rd and 4th arches
7. Pyloric stenosis is characterized by _____________ of muscularis externis in the sphincter
hypertrophy
Decreased pulmonary resistance in the pulmonary vasculature
Urachus/median umbilical ligament; bladder and yolk sac
Mesoderm
8. What is holoprosencephaly? what eye disorder does it result in?
Nicotine; preterm labor
Decreased separation of hemispheres across midline; cyclopia
Diencephalon
Day 6; maintains corpus luteum; 1st trimester
9. When does organogenesis occur?
Mesoderm
Aminoglycosides
Neural crest cells
Week 3-8
10. What is jejunal - ileal - colonic atresia usually due to? What do you see on x ray?
Neuroectoderm
hypospadias
Vascular accident intra uterine; apple peel atresia
Cerebellar tonsillar herniation through foramen magnum
11. How do adults with annular pancreas present? and At What age?
hypertrophy
20-50yrs - Abdominal pain - Postprandial fullness - Nausea - Peptic ulcers - Pancreatitis - Rarely - biliary obstruction
XII
Surface ectoderm
12. what closes the interventricular foramen?
5th
OCPS and maternal diabetes
Physiologic incomplete muscular ventricular septum
Mesdoerm
13. what results if they dont? What can increase the risks of this?
Persistent connection between amniotic cavity and spinal canal; low folic acid
Week 4
StyloPharyngeus
Spinothalamic first
14. How is amniontic fluid excreted? How is amniotic fluid resorped?
lumbosacral
Surface ectoderm
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
15. From What embryonic layer do the ANS arise?
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
Neural crest cells
Alkylating agents
Lacunae in between the chorionic villi
16. Which branchial apparatus develops into the inferior parathyroids?
Lacunae in between the chorionic villi
Dorsal; sensory
3rd pouch
From teh lung;blood from IVC in RA to LA; fossa ovalis
17. What does the ductus arteriosus shunt blood away from - to where? What is its remnant?
Annular pancrease
Neuroectoderm
Fetal and maternal
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
18. What is DiGeorge syndrome and What does it result in?
5th
Fetal kidney; fetal swallows - absorbs - and then removed from placental blood
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
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)
19. What causes persistent Truncus Arteriosus? What does it result in?
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
Synctiotrophoblast; outer; no
Lacunae in between the chorionic villi
Decreases
20. Which branchial derivative accounts for the posterior 2/3 of the tongue?
3rd and 4th arches
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Mesoderm
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
21. What is used to keep the PDA open?
Endoderm
Endoderm - floor of primitive pharynx
Prostaglandins
Foramen cecum and terminal sulus
22. What day is the chorion formed?
3
Neural crest cells
2nd pouch
Sonic Hedgehog
23. What teratogen can cause an absence of digits amongst other things in the fetus? give an example.
Endoderm
Alkylating agents
6th aortic arch
Metencephalon; cerebellum
24. What is duodenal atresia usually due to? What trisomy is it most often seen in?
Failure to recanalize; 21
Cleft lip/palate
After; extrinsic
...
25. what muscles are derived from branchial arch 6? CN?
Mid gut to yolk sac; omphalomesenteric duct; 7th week
...
Dorsal and ventral buds
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
26. Only _______________________________ are associated with neural tube defects
is no longer intact
First branchial pouch
Wolffian; mullerian
arnold chiari associated with thoraclumbar myelomeningocele
27. Which branchial derivative creates the middle ear cavity - eustachian tube and mastoid air cells?
Lots - cleft palate/lip
Failure of bony spinal canal to fuse; no; lower vertebral levels
Tunica vaginalis not fully fused
First branchial pouch
28. what week do the genitalia start to have male/female characteristics? What trimester is that?
A vitelline fistula - failure of vitelline duct to close
Neuroectoderm
Surface ectoderm
Week 10-12; end of 1st trimester
29. From What embryonic layer does the gut tube epithelium arise?
Neuroectoderm
Endoderm
Blastocyst; epiblast and hypoblast; synctiotrophoblast and cytotrophoblast
Where the epiblast and hypoblast fuse
30. From where does the pulmonary arteries and the ductus arteriosus arise?
6th aortic arch
Endoderm
Ventral shaft of penis (penile urethra); labia minora
Week 4; week 3
31. what bone/cartilage and nerves are derived from branchial arch 3?
Pronephros - mesonephros - metanephros; pronephros; most cranially
Mesoderm
Greater horn of hyoid; CN IX (styloPharyngeus)
5th
32. What secretes hCG?
Respiratory distress syndrome
Neural crest cells
Epiblast
Synctiotrophoblast
33. What artery is derived branchial (aortic) arch 2?
Epispadias
Stapedius and hyoid artery
Duodenum to transverse colon; distal transverse colon to rectum
Germinal matrix hemorrhage
34. What are the clinical symptoms that present with syringomelia?
Mesoderm
Bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation
Surface ectoderm
Aortic arch (from left side); right subclavian (on the right)
35. What components do the neural crest cells of the branchial arches give rise to?
Bones - cartilage - and nerves
Week 2; bilaminar disk; epiblast and hypoblast
Wolffian; mullerian
80%
36. What teratogens can cause CN VIII toxicity in the fetus?
T neuroectoderm
Week 10-12; end of 1st trimester
Palpable olive mass in epigastric region; nonbilious projectile vomitting @around 2 weeks
Aminoglycosides
37. What type of blood do umbilical arteries carry? From where to where?
Mesoderm
Mid gut to yolk sac; omphalomesenteric duct; 7th week
1st
Deoxygenated blood; fetal internal iliac arteries to placenta
38. The spinal cord is made from...
not covered
T neuroectoderm
Endoderm
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
39. What germ layer correlates with the branchial pouches?
Surface ectoderm
Surface ectoderm
Endoderm
Week 3; primitive streak formation from the epiblast makes the three layers
40. From What embryonic layer is the kidney and the adrenal cortex from?
Mesoderm
IMA
1st cleft/groove (Ectoderm)
Failure of bony spinal canal to fuse; no; lower vertebral levels
41. How many umbilical arteries are there? How many umbilical veins?
Polyhydramnios
Amniotic epithelium
2; 1
Neural crest cells
42. Other than not having a brain - what else is a symptom of anencephaly? why? hint: think about amniotic fluid
Polyhydramnios
elevated AFP
Cytotrophoblast and synctiotrophoblast
Failure of the urachus to obliterate; outpouching of the bladder
43. What is the kidney that functions at the interim kidney in the 1st trimester? What does it later contribute to?
Fetal alcohol syndrome; mental retardation
Mesonephros; male genital system
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
...
44. What is the 'fetal period'- ie When is it?
Mesoderm
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
Week 8
Female; paramesonephric; mesonephric
45. is epispadias or hypospadias associated with exstrophy of the bladder?
not covered
Epispadias
StyloPharyngeus
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
46. what muscles are derived from branchial arch 4? CN?
StyloPharyngeus
Vascular accident intra uterine; apple peel atresia
Most pharyngeal constrictors - Cricothyroid - levator veli palatini; CN X (superior laryngeal branch - swallowing)
Apical ectodermal ridge
47. From where does pons form from? what else forms from there?
Surface ectoderm
Wolffian; mullerian
Cytotrophoblast
Metencephalon; cerebellum
48. What causes urine discharge from the umbilicus?
Failure of the urachus to obliterate
20-50yrs - Abdominal pain - Postprandial fullness - Nausea - Peptic ulcers - Pancreatitis - Rarely - biliary obstruction
Alkylating agents
After; extrinsic
49. From where is amniotic fluid produced? other than electrolytes and carbs - what else does it contain?
Maternally derived; meconium
Prenatal and perinatal
Week 4
Before getting pregnant!
50. From where does the medulla form?
Myelencephalon
Synctiotrophoblast; outer; no
mesodermal
Greater horn of hyoid; CN IX (styloPharyngeus)