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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 ?
Pataus; fetal alcohol syndrome
28 week onward
Day 6; maintains corpus luteum; 1st trimester
Turners; inferior
2. which posterior fossa malformation results in aqueductal stenosis and hydrocephaly? what other spinal cord lesion does this malformation present with?
Arnold chiari; syringomyelia
Endoderm - floor of primitive pharynx
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
Outgrowth of mesonephric as ureteric bud; most caudal
3. Other than not having a brain - what else is a symptom of anencephaly? why? hint: think about amniotic fluid
Polyhydramnios
Synctiotrophoblast
Initial left to right shunting - then switches
Oligohydramnios
4. What three layers form during gastrulation? From What do they form? and what week does gastrulation occur?
Increase in oxygen concentration which decreases prostaglandin concentration
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Ectoderm - mesoderm - endoderm; epiblast - primitive streak - hypoblast; week 3
Membrane - all 3 from 1st appartus
5. What does the RET gene encode? what neoplasias is it associated with?
Mesdoerm
...
Neural crest development; MEN 2A (pheo - PTH tumor - parafollicular cell tumor)
XII
6. From What embryonic layer does the pineal gland arise?
Ectoderm
Neuroectoderm
Common carotid and internal carotid
Neural crest cells
7. From What embryonic layer do chromaffin cells arise?
Persistent connection between amniotic cavity and spinal canal; low folic acid
Nutrient and gas exchange
Neural crest cells
Ventral; failure of urogenital folds to close
8. Where does fertilization occur?
Ampulla
VACTERL; OCPs and maternal diabetes
Endoderm
All or none
9. Blood coming in the umbilical vein is ____ saturated
Midgut; 10th week
Mental retardation - holoprosencephaly - facial features - fistulas
Bone/cartilage and nerves
80%
10. What are the two walls of the prosencephalon and What do they become?
Cerebral hemisphere - thalami
First branchial pouch
Mesoderm
Muscles of facial expression - stapedius - stylohyoid - posterior belly of the digastric
11. Weeks _______ erythropoiesis takes place in the liver
Medial palatine processes
Bones - cartilage - and nerves
Week 8
6-30
12. what structures are the derivatives of the neural crest cells in branchial arches?
Spinothalamic first
Midgut; 10th week
Bone/cartilage and nerves
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
13. What embryological structure gives rise to the trabeculated part of the left and right atrium?
Metanephric mesenchyme; differentiation and formation of glomerulus and renal tubules to distal convoluted tubule
Primitive atrium
Urogenital sinus; wolffian duct; mullerian duct; urogenital sinus; wolffian duct; wolffian duct; mullerian; mullerian
Alkylating agents
14. What is another name for the mesonephric duct? paramesonephric?
Skewed development of AP septum
Hypospadias
Wolffian; mullerian
Mesonephros; male genital system
15. Where is the apical ectodermal ridge?
Oligohydramnios
1st
Duodenum to transverse colon; distal transverse colon to rectum
Thickened ectoderm at end of each developing limb
16. With the first breath the infant take - pulmonary vasculature resistance _______ which causes an increase in left atrial pressure
Decreases
2nd; 2nd
No organ in each; agenesis no primordial tissue
Reicherts cartilage: Stapes - Styloid process - Lesser horn of hyloid - Stylohyoid ligament and CN VII
17. What gene is produced in the zone of polarizing activity?
Sonic Hedgehog
5th
Foregut; dorsal mesentery (mesodermal)
Fetal and maternal
18. From What embryonic layer does bone of the skulls arise?
VACTERL- vertebral defect - anal atresia - cardiac defects - tracheo - esophageal fistula - renal defects - limb defects
Endoderm lined structures of ear: middle ear cavity - eustacian tube - mastoid air cells
28 week onward
Neural crest cells
19. What causes persistent Truncus Arteriosus? What does it result in?
Hemorrhage - bone deformities
Surface ectoderm
Partial AP septum development; one large vessel leaves the heart - Right to left shunt
From the the lung; blood from SVC that went into RV gets shunted from pulm artery to aorta; ligamentum arteriosum
20. From what aortic arch does the first part of the maxillary artery arise?
1st
Midgut; 10th week
Thickened ectoderm at end of each developing limb
VACTERL; OCPs and maternal diabetes
21. From which branchial derivative does the anterior 2/3 of the tongue develop?
Metencephalon; cerebellum
1st
Fallopian tube - uterus - upper 1/3 of vagina
1st branchial arch
22. Which branchial derivative accounts for taste in the ant 2/3?
Base of limbs in the zone of polarizing activity; ant - post
Polyhydramnios - Down syndrome - Esophageal/duodenal atresia - Imperforate anus - Meckel diverticulum
Branchial arch 2
Ventral ; motor
23. 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
Germinal matrix hemorrhage
secondary palate
4th/5th branchial pouches
24. Which branchial apparatus derivative makes the tympanic membrane of the ear?
Endoderm
Surface ectoderm
Mesencephalon
Membrane - all 3 from 1st appartus
25. From What embryonic layer is the eustachian tube from?
Mesoderm
Maternally derived; meconium
Week 4
Failure of the urachus to obliterate; outpouching of the bladder
26. Which parts of the pancreas contribute to the head - uncinate process and main pancreatic duct?
Fetal alcohol syndrome; mental retardation
Arnold Chiari and Dandy Walker; Arnold Chiari; Dandy Walker; Arnold Chiari
Dorsal and ventral buds
Neuroectoderm
27. What is DiGeorge syndrome and What does it result in?
Aberrant development of 3rd and 4th pouches; t cell def (thymic aplasia) - hypocalcemia (failure of parathyroid development) - CF and CV defects
Fallopian tube - uterus - upper 1/3 of vagina
Turners; inferior
Dorsal; faulty positioning of genital tubercle
28. Septum primum (patent foramen oval) caused by excessive resorption of...
Pronephros - mesonephros - metanephros; pronephros; most cranially
Neuroectoderm
Week 3-8
septum primum and/or secundum
29. What type of blood do umbilical arteries carry? From where to where?
Epispadias
Deoxygenated blood; fetal internal iliac arteries to placenta
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
28 week onward
30. How many components are there to the placenta? What are they called?
Fetal and maternal
All or none
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Pharynx to duodenum; duodenum to transverse colon; distal transverse colon to rectum
31. What artery is derived branchial (aortic) arch 6?
Umbilical - midgut herniates through umbilical ring; SMA
Foregut; dorsal mesentery (mesodermal)
Pataus; fetal alcohol syndrome
Pulm art (prox) and ductus arteriosus
32. To what germ layer does the branchial pouches correlate to?
Mesoderm
Endoderm
A vitelline fistula - failure of vitelline duct to close
Prevent recurrent UTIs
33. From What embryonic layer are the melanocytes from?
Meckels cartilage: mandible - malleus - INCUS - sphenoMandibular ligament; CN V2 and V3
Neural crest cells
Primitive atrium
Hypertrophy of muscularis externis of pylorus; surgical incision
34. What is the allantois become? What is this duct connected to ( on both ends)?
Temporary cervical sinus
Urachus/median umbilical ligament; bladder and yolk sac
Prevent recurrent UTIs
Lacunae in between the chorionic villi
35. what separates the atria from the ventricles?
Lithium; valve leaflets attach to domain down low in RV- 'atrialized RV'
Mullerian inhibitory factor from Sertoli cells; increased androgen from Leydig cells
1st cleft/groove (Ectoderm)
Endocardial cushions
36. From where does pons form from? what else forms from there?
Metencephalon; cerebellum
Neuroectoderm
Week 2; bilaminar disk; epiblast and hypoblast
Glans penis and corpus cavernosum and spongiosum; glans clitoris and vestibular bulbs
37. From what germ layer does the primitive heart tube arise?
Apical ectodermal ridge
Mesoderm
80%
No organ in each; agenesis no primordial tissue
38. What is congenital pharyngocutaneous fistula? and How does it occur?
Neuroectoderm
DiGeorge
Persistence of 3rd cleft (groove) and pouch causes fistula between tonsillar area and cleft in lateral neck
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
39. From What embryonic layer does the epithelial linings of the oral cavity arise?
2; 1
Surface ectoderm
Prostaglandins
No organ in each; agenesis no primordial tissue
40. What causes the transposition of the great vessels? What does it result in?
1st
All intrinsic muscles of larynx except cricothyroid; CN X (recurrent laryngeal nerve - speaking)
Failure to spiral (aorta coming out of RV and PA coming out of left ventricle)- two completely separate systems
Muscles and arteries
41. What separated myometrium of the uterus from the blastocyst?
Decidual basalis
During; instrinsic
Found in lateral neck; from no obliteration of 2-4th clefts
Duodenum to transverse colon; distal transverse colon to rectum
42. What is the 'fetal period'- ie When is it?
Mesoderm; epiblast
From endocardial cushions (ventral and dorsal meet each other)
Diencephalon
Week 8
43. What arises from the fourth aortic arch?
Before getting pregnant!
Aortic arch (from left side); right subclavian (on the right)
Ventral and dorsal parts fail to fuse at 8th week; 2 pancreatic ducts!- more prone to pancreatitis
Thyroid - cricoid - arytenoids - corniculate cuneiform
44. Which arches form the posterior 1/3 of the tongue?
VACTERL- vertebral defect - anal atresia - cardiac defects - tracheo - esophageal fistula - renal defects - limb defects
Arches 3 and 4
Muscles and arteries
Left horn of the sinus venosus
45. What is perinauds syndrome?
Neuroectoderm
Increased AFP and acetycholinesterase (not ACh!) in CSF
Neural crest cells
Caused by compression on trocheal nerve - causes vertical gaze paralysis (associated with arnold chiari)
46. What role does the placenta have?
Nutrient and gas exchange
Decreased pulmonary resistance in the pulmonary vasculature
Indomethacin; blocks PG production
Uretopelvis; most common site for obstruction (hydronephrosis) in fetus
47. What is hypoplasia? is primordial tissue present?
Incomplete; yes
Muscular ventricular septum; no
80%
Medial palatine processes
48. From where does the medulla form?
Day 6; with implantation
Myelencephalon
During; instrinsic
StyloPharyngeus
49. From where does the ureteric bud arise? What does it give rise to?
Renal artery stenosis;
The caudal end mesonephros; the ureter - pelvis - calyces - collecting ducts
Mesoderm
Decreased pulmonary resistance in the pulmonary vasculature
50. what other facial defect other than cyclopia is associated with holoprosencephaly?
Cleft lip/palate
Occiptal
4th/5th branchial pouches
4th week