MCQs

IX EMBRYOLOGY

Questions 137
For each of the following multiple choice questions select the one most appropriate answer:

1. The chromosomal formula of the normal human ovum is:

45 autosomes and 1 X chromosome
44 autosomes and 2 X chromosomes
22 autosomes and 1 Y chromosome
22 autosomes and 1 X chromosome
44 autosomes and 2 Y chromosomes

2. Following ovulation the ovum is viable for up to:

One hour
Twenty-four hours
Three days
Four days
Seven days


_ A_

_ C _

3. The ovum is surrounded by a non-cellular, secreted layer known as the:

Corona radiata

Theca folliculi
Zona pellucida
Cumulus oophorus
Stratum granulosum

4. The spermatozoon is usually viable within the female genital tract for up to:

One hour
Twenty-four hours
Forty-eight hours
Four days
Seven days

5. The usual number of days between fertilization and the commencement of implantation is:

One
Three
Six
Ten
Fourteen

_ C _

_ C _

_ C _

6. The fertilized ovum is completely implanted in the endometrium by the end of the day after fertilization.

Third

Seventh
Fourteenth
Twenty-first
Twenty-eighth

7. Fraternal twins may arise by:

Simultaneous fertilization of two ova
Division of a single fertilized ovum
Duplication of the embryoblast
Duplication of the primitive streak
All of the above mechanisms

8. The uterine cavity is obliterated during pregnancy by fusion of:

Chorion frondosum and decidua basalis
Decidua capsularis and decidua parietalis
Amnion and decidua capsularis
Amnion and chorion
Endometrium and myometrium

_ C _

_ A _

_ B _

9. The embryo is called a fetus after the:


Third week
Eighth week
Twelfth week
Sixteenth week
Twenty-eighth week

10. At the rostral end of the primitive streak lies the primitive:

Spot
Node
Notochord
Plate
Groove

11. At the caudal end of the primitive steak, ectoderm and endoderm meet at the:

Notochordal canal
Coelom
Cloacal membrane
Neural groove
Notochord


_ B _

_ B _

_ C _

12. The neural crest separates off from the:

Neural groove
Neural fold
Neural tube
Neurenteric canal
Neuropore

13. Segmentation is observed in the mesoderm:

Paraxial
Intermediate
Lateral plate
Splanchnic
Branchial


14. The embryonic coelom is formed between the layers of the:

Ectoderm

Mesoderm
Endoderm
Somatopleure
Splanchnopleure

_ B _

_ A _

_ B _

15. The mesenchymal vertebrae are formed from:

Sclerotomes

Myotomes
Dermatomes
Notochord
Cartilage rudiments


16. At birth, the normal umbilical cord contains:

Two umbilical veins

The vitelline duct
The ductus venosus
Two umbilical arteries
The allantois

17. The oral (buccopharyngeal) membrane separates:

Amniotic sac from yolk sac
Nasal cavity from oral cavity
Proctodeum from hindgut
Larynx from pharynx
Stomodeum from foregut

_ A _

_ D _

_ E _

18. The urorectal septum divides the cloaca into:

Rectum and urogenital sinus

Rectum and bladder
Bladder and allantois
Hindgut and bladder
Urethra and anal canal

19. The cloaca of the embryo contributes to the:

Bladder
Ureter
Descending colon
Permanent kidney
Spinal cord

20. The conus regions of both cardiac ventricles are derived from:

Sinus venosus
Primitive atrium
Primitive ventricle
Bulbus cordis
Truncus arteriosus


_ A _

_ A _

_ D _

21. Ductus venosus connects:

Umbilical vein to sinus venosus
Right to left umbilical vein
Pulmonary trunk to aorta
Right to left atrium
Hepatic veins to inferior vena cava

22. The ligamentum arteriosum is derived from the:

Ductus arteriosus
Glomus arteriosus
Conus arteriosus
Truncus arteriosus
Umbilical artery


23. The inguinal canal is created by:

Gubernaculum of gonad

Processus vaginalis
Descent of the gonad
Spermatic cord
External spermatic fascia

_ A _

_ A _

_ A _

24. The mesonephric duct persists as the:

Uterine tube

Round ligament of uterus
Ureter
Ductus (vas) deferens
Nephrons


25. The mesonephros is the permanent kidney of:

Fishes

Amphibia
All mammals
Primates only
Man only

26. Derived from the vitelline duct:

Ductus venosus
Portal vein
Gall bladder
Duodenum
Meckels diverticulum

_ D _

_ B _

_ E _

27. The two embryonic portions of the permanent human kidney are:

Mesonephros and metanephros

Mesonephric duct and metanephros
Metanephric cap and mesonephric duct
Metanephric cap and ureteric diverticulum
Ureteric diverticulum and nephrogenic cord

28. The commonest malformation of the kidney is:

Horseshoe kidney
Congenital cystic kidney
Partial duplication
Unilateral agenesis
Failure of ascent

29. An ectopic testis may be found in the:

Pelvis
Superficial inguinal ring
Inguinal canal
Scrotum
Perineum


_ D _

_ C _

_ E _

30. Origin from second (hyoid) branchial arch:

Trapezius
Temporalis
Occipitofrontalis
Lingual musculature
Lower teeth

31. The premaxilla is formed from the:

Medial nasal processes
The maxillary processes
The lingual swellings
The mandibular arch
The nasal septum


32. Bone ossified from a cartilaginous precursor:

Frontal

Parietal
Zygomatic
Maxilla
None of the above

_ C _

_ A _

_ C _

33. The sulcus limitans of the developing neural tube separates:

Alar lamina from basal lam ma

The alar laminae
The basal laminae
Ependymal layer from mantle layer
Mantle layer from marginal layer


34. The cephalic flexure of the brain Occurs in the region of:

Medulla oblongata

Pons
Midbrain
Diencephalon
Telencephalon

35. The somatic efferent cell column of the primitive neural tube occupies the:

Roof plate
Floor plate
Alar lamina
Basal lamina
Marginal layer

_ A _

_ C _

_ D _

36. Developmentally, the corpus striatum belongs to the:

Telencephalon

Diencephalon
Mesencephalon
Metencephalon
Myelencephalon

37. The last descending tract to undergo myelination

Rubrospinal
Tectospinal
Olivospinal
Corticospinal
Reticulospinal

_ A _

_ D _