IEA Embryology Mock Midterm

March 5, 2003

This exam was prepared by students involved with IEA honor society. It should be used only as a tool to aid you in your studying for the embryology midterm. It should NOT be used as your only study aid. If you have and questions or concerns regarding this mock midterm, please contact Jeremy Rutherford at .

Good Luck!

1.  When is the earliest time that chorionic villi biopsy can be performed?

  1. 7th month
  2. 7th week
  3. 8th month
  4. 8th week

Match the following conditions with the appropriate disease. As always, answers may be used multiple times or not at all.

a) Formed from the union of anterior and posterior cardinal veins

b) enlarges and descends toward septum intermedium

c) opens on the wall of atrium

d) Most common ASD

e) dorsal opening of septum primum

f) none of the above

2.  Sinus venosus____

3.  Ostium primum____

4.  Duct of Cuvier____

5.  Probe patent foramen ovale____

6.  Septum primum____

7.  The midgut of the fetus goes through many rotations starting the 3rd week of life. Which of the following diseases results due to the persistence of the vitellointestinal duct?

  1. Annualar pancreas
  2. Hirshprung disease
  3. Meckel’s diverticulum
  4. Congenital omphaloceole

8.  What germ layer does the heart develop from?

  1. Somatopleuric mesoderm
  2. Splanchnopleuric endoderm
  3. Lateral plate mesoderm
  4. Ectoderm

9.  ______induces the formation of the ______

  1. Primitive node and notochord
  2. Primitive streak and neural tube
  3. Henson’s node node and prochordal plate
  4. Neural tube and Henson’s node

10.  The trophoblasts secrete which of the following?

  1. ACTH
  2. Trophoblastic juice
  3. GH
  4. LH
  5. HCG

11.  What stage in the menstral cycle do the spiral arteries become more coiled and elongated?

  1. Flow Phase
  2. Progesteronic Phase
  3. Menstral Phase
  4. Premestral Phase
  5. Estrogenic Phase

12.  Which of the following is associated with Down’s Syndrome?

  1. Trisomy 22
  2. High levels of HCG
  3. Low levels of HCG
  4. High levels of AFP
  5. Low levels of AFP

13.  How many paris of somites are there on the 23 day if development?

  1. 9
  2. 16
  3. 12
  4. 26
  5. 32

14.  What phase of the menstrual cycle is dominated by high levels of estrogen?

  1. Menstrual phase
  2. Proliferatve phase
  3. Secretory phase
  4. Premenstrual phase
  5. Flow phase

15.  On what day after fertilization does the zona pellucida disintegrate?

  1. 2
  2. 3
  3. 4
  4. 5
  5. 6

16.  Which of the following are sites where blood vessels first appear?

  1. Allantois
  2. Chorion
  3. Amniotic cavity
  4. A and B only
  5. A, B and C

17.  Which of the following correctly describes secondary chorionic villi?

  1. A central core of cellular trophoblasts surrounded by mesenchyme
  2. A central core of syncytiotrophoblasts covered on the periphery by cellular trophoblasts
  3. A central core of mesenchyme covered on the periphery by the cellular and syncytiotrophoblasts
  4. A central core of cellular trophoblasts and a peripheral layer of syncytiotrophoblast
  5. A central core of mesenchyme with blood vessels covered on the periphery by cellular and syncytiotrophoblasts

18.  A young woman who is currently into the 14th week of her first pregnancy comes to you and says she thinks her baby is starting to move around. Being the intelligent St. George’s graduate you are, you tell her:

  1. This is a totally natural occurrence at this stage of her pregnancy
  2. This is actually occurring a little later than normal and you order some tests on the fetus
  3. This being her first pregnancy, her feeling movements this early is expected
  4. This is not normal to feel movements this early and you investigate a possible cause of these movements
  5. You didn’t do well in Embryology in medical school and refer her to someone who knows the answer

19.  Which of the following is not a component of the placental barrier?

  1. Allantois
  2. Endothelial lining of the villous vessels
  3. Connective tissue of the villi
  4. Cytotrophoblasts
  5. Syncytiotrophoblasts

20.  Which of the following forms the urachus?

  1. Yolk sac
  2. Connecting stalk
  3. Allantois
  4. Chorion
  5. Amnion

21.  In the development of the lung, which stage occurs first?

  1. Alveolar stage
  2. Terminal sac stage
  3. Canalicular stage
  4. Psuedo-glandular stage

22.  The Tetralogy of Fallot consists of all the following except:

  1. Pulmonary stenosis
  2. Mitral valve defect
  3. Hypertrophy of right ventricle
  4. Over riding of aorta
  5. Ventricular septal defect

23.  The cloacal sphincter differentiates into all the following muscles except:

  1. Sphincter ani externus
  2. Bulbospongiosus
  3. Ischiocavernosus
  4. Levator ani
  5. Superficial transverse perineal muscle

24.  Which of the following results from the absence of parasympathetic ganglia in a segment of the descending or sigmoid colon?

  1. Meckel’s diverticulum
  2. Subhepatic cecum
  3. Congenital omphalocoele
  4. Hirschsprung disease
  5. Hiatial hernia

25.  Which of the following is not a collecting part of the adult kidney?

  1. Ureter
  2. Bowman’s capsule
  3. Major calyces
  4. Minor calyces
  5. Arched tubules

26.  Which of the following results from the complete non-obliteration of the allantois?

  1. Urachal sinus
  2. Urachal fistula
  3. Urachal cyst
  4. Umbilical fistula
  5. Umbilical cyst

27.  The normal site of fertilization is

  1. Vagina
  2. Cervix
  3. Ampulla of fallopian tube
  4. Ovary

28.  Nucleus Pulposus is a persisting remnant of the

  1. Primitive streak
  2. Notochord
  3. Allantois
  4. Prochordal plate

29.  Neural crest cells give rise to all the following EXCEPT

  1. Schwann cells
  2. Pigment cells
  3. Pia and arachnoid
  4. Retina

30.  The muscles of the larynx develop from the mesoderm of:

  1. 3rd arch
  2. 4th and 6th arches
  3. 4th and 5th arches
  4. none of the above

31.  Placenta

  1. Is delivered during the 2nd stage of labor
  2. Its maternal surface is smooth
  3. Its fetal component develops from the chorion laeve
  4. Its normal site of attachment is the posterior wall of the uterus

32.  The cartilage and musculature of the trachea develop from:

  1. 4th arch mesoderm
  2. 6th arch mesoderm
  3. both a and b
  4. splanchnopleuric mesoderm

33.  Capacitation of the spermatozoa occurs in the:

  1. Seminiferous tubules
  2. Epididymis
  3. Female genital tract
  4. Seminal vesicle

34.  The blastocyst becomes completely embedded in the uterine stroma by the:

  1. 2nd day
  2. 6th day
  3. 12th day
  4. 18th day

35.  The inner cell mass gives rise to all the following EXCEPT:

  1. Amnion
  2. Yolk sac
  3. Hypoblasts
  4. Embryotroph

36.  The neural tube is induced to form from ectoderm by:

  1. Neural crest cells
  2. The notochord
  3. Secondary mesoderm
  4. Primitive streak

37.  Parietal pleura is formed from:

  1. Endoderm
  2. Splanchnic mesoderm
  3. Ectoderm
  4. Somatic mesoderm

38.  The deciduas basalis:

  1. Overlies the conceptus
  2. Forms the basal portion of the embryo
  3. Forms the maternal portion of the placenta
  4. Is the largest part of the deciduas

39.  The developing larynx undergoes recanalization by the:

  1. 8th week
  2. 6th week
  3. 10th week
  4. 12th week

40.  A fetus is born prematurely at 28 weeks, the mother would like to know if the fetus is a capable of surviving. You tell the mother:

  1. yes, the fetus will survive because although the lung is not mature, respiration is possible
  2. yes, the fetus will survive because it has adequate terminal sacs and surfactant to permit survival
  3. no, the fetus will not survive because there are no respiratory structures

41.  Lung Hypoplasia is associated with :

  1. agenesis of lung
  2. oligohydramnios
  3. renal agenesis
  4. a and c
  5. b and c

42.  The tubular heart is suspended into the pericardial cavity from the ventral side of the foregut by the:

  1. epimyocardial mantle
  2. splanchnic mesoderm
  3. pericardium
  4. dorsal mesocardium

43.  The tubular heart in order from caudal to cranial is as follows:

  1. sinus venosus, atrium, atrioventricular canal, ventricle, bulbous cordis, truncus arteriosus
  2. ventricle, atrium, bulbous cordis, truncus arteriosus, sinus venosus, atrioventricular canal
  3. atrium, sinus venosus, atrioventricular canal, ventricle, bulbous cordis, truncus arteriosus
  4. truncus arteriosus, atrioventricular canal, atrium, sinus venosus, bulbous cordis

44.  The septum spurium is formed by ______; the septum intermedium is formed by ______.

  1. dorsal and ventral endocardial cushions; right and left venous valves
  2. right and left venous valves; dorsal and ventral endocardial cushions
  3. right and left endocardial cushions; dorsal and ventral venous valves
  4. none of the above

45.  Pulmonary stenosis, ventricular septal defect and hypertrophy of right ventricle are associated with:

  1. persistent truncus
  2. Tetrology of Fallot
  3. Tertiology of Fallot
  4. Di George’s Syndrom

Questions 46-49, match the embryological structure to its adult remnant. Each choice can be used once or not at all.

a)  Sinus venarum

b)  Anterior part of right atrium

c)  Pulmonary vein

d)  Anterior part of left atrium

e)  Posterior part of left atrium

46.  Right horn of sinus venosus____

47.  Proximal portions of primitive pulmonary veins____

48.  Left half of primitive atrium____

49.  Right half of primitive atrium____

50.  The dorsal mensentery of the gut is derived from ______; the ventral mesentery is dervived from.

  1. Ectoderm; endoderm of the yolk sac
  2. Endoderm of the yolk sac; splanchnic mesoderm
  3. Septum transversum; endoderm of the yolk sac
  4. Splanchnic mesoderm; septum transversum

51.  Congenital omphalocoele results from the:

  1. Non-rotation of the midgut
  2. Reverse rotation of the hindgut
  3. Failure of the reduction of the physiological hernia of the midgut loop
  4. Failure of fixation

52.  Ectopic implantions most commonly occur in the

  1. Ovary
  2. Abdomen
  3. Uterine tube
  4. Cervix
  5. Peritoneal cavity

53.  The normal chromosome number of a human sermatid is

  1. 23 autosomes plus 2 different sex chromosomes
  2. 22 autosomes plus and X and Y chromosome
  3. 23 autosomes plus 2 identical sex chromosomes
  4. 22 autosomes plus and X or a Y chromosome

54.  The head and tail folds are due to what?

  1. Primitve streak
  2. Elongation of the neural tube
  3. Elongation of the notochord
  4. Growth of somites in a caudal and cephalic direction

55.  Multigravida is:

  1. Extrusion of the yolk sac through the primitive umbilical opening
  2. First birth
  3. Second birth
  4. Premature rupture of the colacal membrane

56.  The most frequently used method for measuring the length of 6-week old embryos is

  1. Greatest length
  2. Standing height
  3. Crown-Rump (CR) length
  4. Crown-heel (CH) length
  5. Total length

57.  The endothelial linings of the blood vessels are fromed from

  1. Angioblastic cells
  2. Haemangioblastic cells
  3. Hypoblastic cells
  4. Trophoblastic cells

58.  All of the following about the valves of the primitive heart are incorrect except

  1. The right venous valve merges with interatrial septum
  2. The lower part of the right venous valve forms the valve of the superior vena cava and the valve of the coronary sinus
  3. The upper part of the right venous valve forms the crista terminalis
  4. The left venous valve forms the valve of the coronary sinus

59.  The cloacal membrane is made up of

  1. Endoderm
  2. Endoderm and mesoderm
  3. Endoderm and ectoderm
  4. Ectoderm and mesoderm
  5. Ectoderm

60.  The anterior neuropore closes on day______. If this does not occur the teratologic condition that arises is known as______

  1. 25, persistent neurenteric canal
  2. 27, meroanencephaly
  3. 25, anencephaly
  4. 27, persistent neurenteric canal

61.  Intraembryonic celomic clefts appear in the:

  1. Lateral plate mesoderm
  2. Paraxial mesoderm
  3. Intermediate mesoderm
  4. Somites
  5. Primary mesoderm

62.  The thoracic diaphragm, which separates the pleural and peritoneal cavities is formed by the fusion of:

  1. Septum transversum
  2. Pleuroperitoneal membranes
  3. Primitive dorsal mesentery
  4. Body wall mesenchyme
  5. All of the above

63.  The secreting part of the kidney is formed from the:

  1. Pronephros
  2. Mesonephros
  3. Metanephric cap
  4. Ureteric bud
  5. Wolffian duct

64.  Each horn of the sinus venosus receives this vein from the yolk sac

  1. Vitelline vein
  2. Umbilical vein
  3. Anterior cardinal vein
  4. Common cardinal vein

65.  A 24 year-old female states that she has a very regular menstrual cycle that is 27 days in length. The projected time of ovulation for this woman would be about the:

  1. 14th day following the beginning of her last menstrual period.
  2. 13th day following the beginning of her last menstrual period.
  3. 12th day following the beginning of her last menstrual period.
  4. 12th day following the end of her last menstrual period.
  5. 13th day following the end of her last menstrual period.

1. D 47. E

2. F 48. D

3. F 49. B

4. A 50. D

5. D 51. C

6. B 52. C

7. C 53. D

8. A 54. B

9. A 55. C

10. E 56. C

11. B 57. A

12. E 58. C

13. C 59. C

14. B 60. C

15. D 61. A

16. D 62. E

17. C 63. C

18. D 64. A

19. A 65. B

20. C

21. D

22. B

23. D

24. D

25. B

26. B

27. C

28. B

29. D

30. B

31. D

32. D

33. C

34. D

35. D

36. B

37. D

38. C

39. C

40. B

41. E

42. D

43. A

44. B

45. B

46. A