Download IX EMBRYOLOGY

IX EMBRYOLOGY
Questions 1—37
For each of the following multiple choice
questions select the one most appropriate
answer:
1. The chromosomal formula of the normal
_ A_
human ovum is:
A. 45 autosomes and 1 X chromosome
B. 44 autosomes and 2 X chromosomes
C. 22 autosomes and 1 Y chromosome
D. 22 autosomes and 1 X chromosome
E. 44 autosomes and 2 Y chromosomes
2. Following ovulation the ovum is viable for up
to:
A. One hour
B. Twenty-four hours
C. Three days
D. Four days
E. Seven days
_C_
3. The ovum is surrounded by a non-cellular,
_C_
secreted layer known as the:
A. Corona radiata
B. Theca folliculi
C. Zona pellucida
D. Cumulus oophorus
E. Stratum granulosum
4. The spermatozoon is usually viable within
_C_
the female genital tract for up to:
A. One hour
B. Twenty-four hours
C. Forty-eight hours
D. Four days
E. Seven days
5. The usual number of days between
fertilization and the commencement of
implantation is:
A. One
B. Three
C. Six
D. Ten
E. Fourteen
_C_
6. The fertilized ovum is completely implanted
_C_
in the endometrium by the end of the — day
after fertilization.
A. Third
B. Seventh
C. Fourteenth
D. Twenty-first
E. Twenty-eighth
7.
Fraternal twins may arise by:
_A_
A. Simultaneous fertilization of two ova
B. Division of a single fertilized ovum
C. Duplication of the embryoblast
D. Duplication of the primitive streak
E. All of the above mechanisms
8.
The uterine cavity is obliterated during
pregnancy by fusion of:
A. Chorion frondosum and decidua basalis
B. Decidua capsularis and decidua parietalis
C. Amnion and decidua capsularis
D. Amnion and chorion
E. Endometrium and myometrium
_B_
9.
The embryo is called a fetus after the:
_B_
A. Third week
B. Eighth week
C. Twelfth week
D. Sixteenth week
E. Twenty-eighth week
10. At the rostral end of the primitive streak
_B_
lies the primitive:
A. Spot
B. Node
C. Notochord
D. Plate
E. Groove
11.At the caudal end of the primitive steak,
ectoderm and endoderm meet at the:
A. Notochordal canal
B. Coelom
C. Cloacal membrane
D. Neural groove
E. Notochord
_C_
12. The neural crest separates off from the:
_B_
A. Neural groove
B. Neural fold
C. Neural tube
D. Neurenteric canal
E. Neuropore
13. Segmentation is observed in the —
_A_
mesoderm:
A. Paraxial
B. Intermediate
C. Lateral plate
D. Splanchnic
E. Branchial
14. The embryonic coelom is formed between
the layers of the:
A. Ectoderm
B. Mesoderm
C. Endoderm
D. Somatopleure
E. Splanchnopleure
_B_
15. The mesenchymal vertebrae are formed
_A_
from:
A. Sclerotomes
B. Myotomes
C. Dermatomes
D. Notochord
E. Cartilage rudiments
16. At birth, the normal umbilical cord
_D_
contains:
A. Two umbilical veins
B. The vitelline duct
C. The ductus venosus
D. Two umbilical arteries
E. The allantois
17. The oral (buccopharyngeal) membrane
separates:
A. Amniotic sac from yolk sac
B. Nasal cavity from oral cavity
C. Proctodeum from hindgut
D. Larynx from pharynx
E. Stomodeum from foregut
_E_
18. The urorectal septum divides the cloaca
_A_
into:
A. Rectum and urogenital sinus
B. Rectum and bladder
C. Bladder and allantois
D. Hindgut and bladder
E. Urethra and anal canal
19. The cloaca of the embryo contributes to the:
_A_
A. Bladder
B. Ureter
C. Descending colon
D. Permanent kidney
E. Spinal cord
20. The conus regions of both cardiac ventricles
are derived from:
A. Sinus venosus
B. Primitive atrium
C. Primitive ventricle
D. Bulbus cordis
E. Truncus arteriosus
_D_
21. Ductus venosus connects:
_A_
A. Umbilical vein to sinus venosus
B. Right to left umbilical vein
C. Pulmonary trunk to aorta
D. Right to left atrium
E. Hepatic veins to inferior vena cava
22. The ligamentum arteriosum is derived from
_A_
the:
A. Ductus arteriosus
B. Glomus arteriosus
C. Conus arteriosus
D. Truncus arteriosus
E. Umbilical artery
23. The inguinal canal is created by:
A. Gubernaculum of gonad
B. Processus vaginalis
C. Descent of the gonad
D. Spermatic cord
E. External spermatic fascia
_A_
24. The mesonephric duct persists as the:
_D_
A. Uterine tube
B. Round ligament of uterus
C. Ureter
D. Ductus (vas) deferens
E. Nephrons
25. The mesonephros is the permanent kidney
_B_
of:
A. Fishes
B. Amphibia
C. All mammals
D. Primates only
E. Man only
26. Derived from the vitelline duct:
A. Ductus venosus
B. Portal vein
C. Gall bladder
D. Duodenum
E. Meckel’s diverticulum
_E_
27. The two embryonic portions of the
_D_
permanent human kidney are:
A. Mesonephros and metanephros
B. Mesonephric duct and metanephros
C. Metanephric cap and mesonephric duct
D. Metanephric cap and ureteric
diverticulum
E. Ureteric diverticulum and nephrogenic
cord
28. The commonest malformation of the kidney
_C_
is:
A. Horseshoe kidney
B. Congenital cystic kidney
C. Partial duplication
D. Unilateral agenesis
E. Failure of ascent
29. An ectopic testis may be found in the:
A. Pelvis
B. Superficial inguinal ring
C. Inguinal canal
D. Scrotum
E. Perineum
_E_
30. Origin from second (hyoid) branchial arch:
_C_
A. Trapezius
B. Temporalis
C. Occipitofrontalis
D. Lingual musculature
E. Lower teeth
31. The premaxilla is formed from the:
_A_
A. Medial nasal processes
B. The maxillary processes
C. The lingual swellings
D. The mandibular arch
E. The nasal septum
32. Bone ossified from a cartilaginous
precursor:
A. Frontal
B. Parietal
C. Zygomatic
D. Maxilla
E. None of the above
_C_
33. The sulcus limitans of the developing neural
_A_
tube separates:
A. Alar lamina from basal lam ma
B. The alar laminae
C. The basal laminae
D. Ependymal layer from mantle layer
E. Mantle layer from marginal layer
34. The cephalic flexure of the brain Occurs in
_C_
the region of:
A. Medulla oblongata
B. Pons
C. Midbrain
D. Diencephalon
E. Telencephalon
35. The somatic efferent cell column of the
primitive neural tube occupies the:
A. Roof plate
B. Floor plate
C. Alar lamina
D. Basal lamina
E. Marginal layer
_D_
36. Developmentally, the corpus striatum
_A_
belongs to the:
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
37. The last descending tract to undergo
myelination
A. Rubrospinal
B. Tectospinal
C. Olivospinal
D. Corticospinal
E. Reticulospinal
_D_