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EMBRYOLOGY
1. Which of the following synthesize progesterone?
a) Cytotrophoblast
Syncytiotrophoblast b)
c) Both A and B
d) Neither A or B
2. All occur during the morula stage except:
Attachment to the uterine epithelium takes place a)
b) The location of the cells dictates their fate
c) The outer cells pump fluid creating a fluid-filled blastocele
d) Tight junctions appear between cells at the periphery, isolating the inner
Cells from the uterine fluid
3. During the first week of human development:
a) The zona pellicoda is formed
e smallerThe cells of the embryo increase in number but becom b)
c) The cells of the embryo increase in size
d) Implantation is completed
e) None of the above
4. During the second week of human development:
a) The trophoblast differentiates into cytotrophoblast & syncytiotrophoblast
b) The utero-placental circulation begins
c) The inner cell mass differentiation into hypoblast and epiblast
d) Primary stem villi appear
ll of the aboveA e)
5. As a result of transverse and longitudinal folding of the embryo:
a) The prochordal membrane is moved ventrally and caudally
b) Position of yolk sac becomes incorporated into embryonic body
c) The primitive groove is moved cranially & dorsally
Both A and B d)
e) All of the above
6. Which of the following is/are normally always interposed between fetal and
maternal blood:
a) Extraembronic mesoderm
b) Maternal endothelial cells
Syncytiotrophoblast c)
d) Both A and B
e) All of the above
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7. Maternal blood normally comes into contact with:
Syncytiotrophoblast a)
b) Cytotrophoblast
c) Fetal blood cells
d) Both A and B
e) All of the above
8. Which of the following is not a function of the yolk sac in humans?
a) Site of origin of primodial germ cells
b) Site of origin of fetal blood cells
Provides nourishment/metabolic reserves for the embryo c)
d) Site of origin of epithelium of the primitive gut
e) Facilitates transfer of nutrients into the early embryo
9. At the time of ovulation the endometrium is in the:
a) Menstral phase
b) Early proliferative phase
Late proliferative phase c)
d) Early secretory phase
e) Late secretory phase
10. Lines in the chorionic after the third developmental week are:
a) Cytotrophoblast
b) Syncytiotrophopblast
c) Both A and B
Neither A nor B d)
11. Always normally situated between maternal and fetal blood:
a) Cytotrophoblast
Syncytiotrophoblast b)
c) Both A and B
d) Neither A nor B
day of development:
th
. Bleeding may occur near the 1312
a) May be confused with normal menstral bleeding
b) Is caused by increased blood flow into lacunar spaces
Both A and B c)
d) Neither A nor B
13. The extraembryonic membrane which contributes the most tissue to the
formation of the placenta is the:
a) Amnion
b) Chorion
c) Yolk sac
Connecting (body) stalk d)
e) Decidua
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14. The extraembryonic epiblast gives rise to or contributes cells to which of the
following germ layers?
a) Ectoderm
b) Mesoderm
c) Endoderm
d) Both A and B
All of the above e)
15. The primitive streak:
a) Is derived from the outer cells of the morula
b) Is formed during the second week in development
c) Persists as the cloacal membrane
Is the site of involution of epiblast cells to form mesoderm d)
16. The bilaminar germ disc:
Consists of hypoblast and epiblast a)
b) Is derived from trophoblast cells
c) Both A and B
d) Neither A nor B
17. Meiosis is completed within the gonads during gametogenesis in which sex?
a) Gametogenesis in human female
Gametogenesis in human male )b
c) Both A and B
d) Neither A nor B
18. Female pronucleus are fully formed:
a) Before fertilization
b) After fertilization
c) Both A and B
Neither A nor B d)
19. The conceptus is the:
a) Embryo/fetus
b) Amnion and Chorion
c) Deciduas
Both A and B d)
e) All of the above
20. Functions of the placenta include all the following except:
Exchange of maternal and fetal blood a)
b) Exchange of nutrients and electrolytes
c) Hormone production
d) Gas exchange
e) Transmission of maternal antibodies
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21. The secondary oocyte undergoes completion of the second maturation
division:
a) Before ovulation
At fertilization b)
c) After ovulation
d) Prenatally
e) At puberty
22. The ovarian follicular cells release:
a) Follicle stimulating hormone
b) Chorionic Gonadotrophin
Estrogen c)
d) Both A and B
e) All of the above
23. The most common site for implantation in ectopic pregnancy is the::
a) Internal os of the uterus
b) Mesentary
c) Ovary
Oviduct d)
e) None of the above
24. At the time of initiation of implantation:
a) The endometrium is in the proliferative phase
The predominant ovarian hormone is progesterone b)
c) The conceptus is approximately one day "old" (postfertilization)
d) Both A and B
e) All of the above
25. All is true about primary oocytes except:
a) Are arrested in prophase of the first meiotic division
Continue to form after birth b)
c) Together, with surrounding epithelial cells, for a primordial follicle
d) Suffer from atretion until only approximately 40, 000 are left at puberty
26. Trophoblast and inner cell mass portions are evident in the:
a) Conceptus before implantation has started
b) Conceptus after implantation has started
Both A and B c)
d) Neither A nor B
27. At fertilization:
meiotic division
nd
pletes the 2The ovum coma)
b) Cleavage is initiated
c) The sex of the individual is determined
d) The diploid number of chromosomes is restored
All of the above e)
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28. All the following are derivatives of mesoderm except:
a) Dermatomes
b) Myotomes
c) Sclerotomes
d) Endothelium
Yolk sac e)
29. The prechordal plate:
a) Is a patent inducer region for future head structures
b) Becomes a portion of the oropharyngeal membrane
c) Is formed within the embryonic epiblast
Both A and B d)
e) All of the above
30. At the time of fertilization, the endometrium is in the:
Proliferative phase a)
b) Secretory phase
c) Menstral phase
d) Both B and C
31. Which of the following contains abundant nutrient reserves?
a) Female gametes
b) Male gametes
c) Both A and B
Neither A nor B d)
32. Which of the following determines the genetic sex of the zygote?
a) Female gametes
Male gametes b)
c) Both A and B
d) Neither A nor B
33. Which of the following is found in the early placenta?
a) Cytotrophoblast
b) Syncytiotrophoblast
Both A and B c)
d) Neither A nor B
34. The space between the somatopleuric and splanchnopleuric extraembryonic
mesoderm is known as:
a) The primitive yolk sac
b) The secondary yolk sac
c) The blastocele
d) The amniotic cavity
The extraembryonic coelom )e
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35. As a result of fertilization:
a) Sex of the offspring is determined
b) The diploid number of chromosomes is restored
c) Cleavage divisions are initiated
d) Genetic heterogeneity is maintained
above All of the e)
36. At the time of the first missing menstrual period, the conceptus is:
a) 3 days old
b) 5 days old
3 weeks old c)
d) 5 weeks old
37. Primary oocytes have developed by the time of birth. From puberty to
menopause, these germ cells remain suspended in the meiotic prophase. The
oocyte of a mature follicle is induced to undergo the first meiotic division just
prior to ovulation as a result of which of the following hormonal stimuli:
a) The cessation of progesterone secretion
b) The gradual elevation of FSH titers
c) The low estrogen titers associated with the maturing follicle
d) The slow elevation of progesterone produced by luteal cells
e surge of luteinizing hormone initiated by high estrogen titersTh e)
day of development, fluid accumulation by the morula results is
th
38. By the 4
separation of the cells into trophoblasts and embryoblasts, or inner cell mass.
pment, the role of trophoblasts includes all of the day of develo
th
12-
th
From the 8
following except:
Enclosure of inner cell mass and blastocyst cavity a)
b) Formation of embryo proper
c) Invasion of endometrial epithelium
d) Production of hormones
e) Production of 2 distinct cell populations by differentiation
for 3 days. Since
o
39. A 26 year old man had viral influenza with fever 39.5
, he was left
o
spermatogenesis cannot occur above a scrotal temperature of 35.5
with no viable sperm on his recovery. The time required for spermatogenesis,
spermiogenesis, passage of a viable sperm to the epididymis is approximately:
a) 3 days
b) 1 week
c) 5 weeks
2 months d)
e) 4 months
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40. A 25 year old female states that she has a very regular menstrual cycle that is
24 days in length. The projected time of ovulation for this woman would be
about the:
day following start of her last menstrual period
th
14 a)
day following end of her last menstrual period
th
12 b)
day following end of her last menstrual period
th
12 c)
day following end of her last menstrual period
th
10 d)
al periodday following beginning of her last menstru
th
10 e)
41. The chorionic villi of the placenta are most numerous in the region of the:
a) Decidua capsularis
Chorionic plate b)
c) Basal plate
d) Maternal septae
e) Decidua basalis
42. The following list contains components of the "placental barrier" during the
first trimester of pregnancy. Which one component is disappearing during late
pregnancy?
a) The endothelial lining of fetal capillaries
The cytotrophoblast b)
c) The syncytiotrophoblast
d) The basement membrane of fetal capillaries
e) None of the above
43. All of the following placental transport mechanism require the expenditure of
cellular energy except:
a) Active transport
b) Pinocytosis
Simple diffusion c)
d) Facilitated diffusion
44. A full-term male infant has vomited 1 hour after suckling. There has been
failure to gait during the first 2 weeks postnatal. The vomitus is not bile-stained
and no respiratory dilation is evident. Wxamination reveals an abdomen neither
tense nor bloated. The most probable explaination is:
Congenital hypertrophic pyloric stenosis a)
b) Duodenal atresia
c) Patient ileal diverticulum
d) Imperforate anus
e) Tracheo-esophageal fistula
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45. A fistula is found that runs between the palatine tonsil fossa and the skin of
the neck immediately anterior to the sternocleidomastoid muscle. Developmetal
failure occured:
a) With a rupture of the tissue between the third branchial cleft and third
pharyngeal pouch
b) With a failure to close the first branchial cleft
With a failure to obliterate the cervical sinus c)
d) Both A and B
e) All of the above
46. Which statement about fetal blood vessels is false:
a) The ductus arteriosus carries blood from the aorta to the pulmonary trunk
b) The foramen ovale carries blood from the right atrium to the left atrium
The umbilical vein carries blood from the umbilical cord via the ductus c)
venosus to the inferior vena cave
d) Implantation is completed
e) None of the above
47. Regarding the blastocyst all the following are true except:
a) Has more cells than a morula
b) Has inner cell mass
Has syncytotrophoblast c)
d) Has trophoblast cells
e) May have zona pellucida
48. Derivatives of the mesodermal cell layer of the embryo include all the
following except:
a) Adrenal cortex
b) Gonads
c) Peritoneal serosa
d) Spleen
Liver parenchyma e)
49. In the developing embryo, the first bone to begin ossification is the:
a) First rib
b) Humerus
c) Tibia
d) Scapula
Clavicle e)
50. Fallot's tetralogy includes all the following except:
a) Pulmonary stenosis
b) Aortic overriding
c) Ventricular septal defect
Patency of ductus arteriosus d)
e) Hypertrophy of the right ventricle
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51. The trachea develops from the:
a) Septum transversum
Fifth branchial arch b)
c) Thyroglossal canal
d) Pulmonary mesenchyme
e) Foregut
52. In the developing pancreas, the dorsal bud contributes all the following
except:
a) Body of the pancreas
b) Distal portion of the main pancreatic duct
c) Secondary pancreatic duct
Uncinate process d)
e) Upper half of the head of the pancreas
53. All of the following structures contribute in development of diaphragm
except:
a) Body wall
b) Primitive mesoesophagus
c) Septum transversum
ardial membraneperic-Pleuro d)
e) Pleuro-peritoneal membrane
54. Spina bifida is a failure of fusion between the:
a) Left and right halves of the vertebral column
b) Pedicle and centrum of the vertebra
minae of the vertebraLeft and right la c)
d) Both A and B
e) All of the above
55. A urachal fistula represents a remnant of the:
a) Cloaca
Allantois )b
c) Urogenital sinus
d) Hindgut
e) Mesonephric duct
56. What is the origin of the mucosa of the middle ear?
a) Neural ectoderm
b) Surface ectoderm
c) Mesoderm
Endoderm d)
e) None of the above
57. The left sixth aortic arch gives rise to the:
a) Hemiazygos vein
b) Coronary sinus
Ligamentum arteriosum c)
d) Ligamentum venosum
e) No remnants are found in this structure in the adult
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58. The posterior pituitary is of which origin:
a) Endoderm
b) Mesoderm
c) Ectoderm
Endoderm and mesoderm d)
e) Endoderm and ectoderm
59. The parathyroid glands:
a) They are 3 in number
b) They secrete Calcitonia
pharyngeal arch
nd
They develop from the 2c)
d) They normally lie anterior to the thyroid gland
pharyngeal arches (pouches)
th
and 4
rd
They develop from the 3 e)
60. Unilateral upper lip cleft is due to failure of fusion of:
a) Medial nasal processes
b) Maxillary and lateral nasal processes
Maxillary and medial nasal processes on one side c)
d) Maxillary and mandibular processes
e) Medial and lateral nasal processes unilaterally
61. In which of the following is precursor cell mitosis evident after puberty:
a) Female gametes
Male gametes b)
c) Both A and B
d) Neither A nor B
62. What is the origin of the mucosa of the oral pharynx?
a) Branchial arch I
b) Branchial arch II
Branchial arch III c)
d) Branchial arch IV
e) Not of branchial arch origin
63. Which of the following is formed from portions of one sclerotome:
a) Vertebral centrum
Intervertebral disc (annulus fibrosus) b)
c) Both A and B
d) Neither A nor B
64. The clavicle is:
a) The first bone to begin ossification
The first bone to complete ossification b)
c) Intramembranous in origin
d) Both A and C
e) All of the above
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65. Limb musculature:
a) Relies on spinal nerve to aid the differentiation process
b) Begins as mesenchymal condensation
c) Is derived from somatic mesoderm
d) Splits into flexor and extensor compartments
All of the above e)
66. Cervical sinus develop from:
a) Pharyngeal pouch 1
b) Pharyngeal pouch 2
c) Pharyngeal pouch 3
d) Pharyngeal pouch 4
This structure is not derived from pharyngeal pouch e)
67. Parafollicular cells of the thyroid gland develop from:
a) Pharyngeal pouch 1
b) Pharyngeal pouch 2
c) Pharyngeal pouch 3
Pharyngeal pouch 4 d)
e) This structure is not derived from pharyngeal pouch
68. During the third to sixth months of pregnancy, the structure primarily
responsible for erythropoiesis is the:
a) Bone marrow
Liver b)
c) Spleen
d) Thymus
e) Yolk sac
69. Structures derived from the hind gut in the male include all the following
except the:
Allantois a)
b) Descending colon
c) Inferior portion of the anal canal
d) Prostatic urethtra
e) Urinary bladder
70. With regard to the formation of the placenta all of the following are false
except:
Tertiary chorionic villi differ from primary chorionic villi by the presence a)
of blood vessels
b) Primary chorionic villi contain only syncytiotrophoblast
c) The intervillous space contains fetal blood
d) The deciduas basalis and the chorion leave constitute the placenta
e) The umbilical cord contains a loose connective tissue called Wharton's jelly
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71. The endocardial cushions are involved in the formation of all of the following
except:
Right and left atrioventricular canals a)
b) Pectinate muscles
c) Atrioventricular valves
d) Membranous part of the interventricular septum
72. Which of the following is the most common type of congenital heart
malformation?
a) Dextrocardia
Atrial septal defect b)
c) Ectopic cordis
d) Ventricular septal defect
e) Transposition of the great vessels
73. The adult left atrium is derived embryologically primarily from the:
a) Right horn of the sinus venosus
Primitive pulmonary vein )b
c) Sinus venarum
d) Bulbus cordis
e) Ledt horn of the sinus venosus
74. The primitive aortic arch pattern is transformed into an adult arterial
arrangement. Which pair of arteries (embryonic/adult) is incorrect:
arch/ pulmonary artery
th
6 a)
arch/ right subclavian
th
4Right b)
arch/ left subclavian
th
Left 4 c)
arch/ stapedial artery
nd
2 d)
arch/ common and internal carotid
rd
3 e)
75. Azygos vein is derived from the:
a) Right vitelline vein
b) Right subcardinal vein
c) Right anterior cardinal
Right supracardinal vein d)
e) All of the above
76. All of the following are true concerning development of the bronchi except:
a) Lung buds first form at the caudal end of the laryngotracheal tube
week of development, the lung bud grows laterally into the
th
During the 5 b)
primitive pleural cavities (pericardioperitoneal canals)
c) Third generation bronchi supply bronchopulmonary segments
The pulmonary cartilage, smooth muscle, and connective tissue are derived d)
from the lung bud endoderm
e) By 24 weeks of development, respiratory bronchioles are present
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77. Tracheoesophageal fistula with blind ending esophagus results in:
a) Polyhydraminos (more than usual amount of amniontic fluid)
Oligohydraminos (less than usual amount of amniotic fluid) b)
c) Both A and B
d) Neither A nor B
78. The definitive diaphragm is formed by fusions of all except one of the
following:
a) Mesoesophagus
b) Septum transversum
c) Pleuroperitoneal membranes
esentery of duct of CavierM d)
e) Mesoderm of the body wall
79. Paraxial (somite) mesoderm gives rise to:
a) Muscles of mastication
b) Muscles in the stomach
c) Both A and B
Neither A nor B d)
80. The embryonic epiblast gives rise to or contributes cells to which of the
following germ layers?
a) Ectoderm
b) Mesoderm
c) Endoderm
d) Both A and B
All of the above e)
81. Gonia cells produced during gametogenesis are usually present in 65-year old
individuals of which sex:
a) Gametogenesis in human female
Gametogenesis in human male b)
c) Both A and B
d) Neither A nor B
82. All of the following are true of amniotic fluid except:
a) It is derived from maternal blood
month
th
b) It is swallowed by the fetus from the beginning of the 5
It restricts fetal movement within the amniotic cavity c)
d) It absorbs jolts to the fetus
83. Epithelium of the tongue posterior to the sulcus terminals is derived from
the:
a) First branchial arch
b) Second branchial arch
Third branchial arch c)
d) Fourth branchial arch
e) Not of branchial arch origin
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84. What is the origin of the superior parathyroid glands?
a) Pharyngeal pouch I
b) Pharyngeal pouch II
c) Pharyngeal pouch III
ch IVPharyngeal pou d)
e) Not of pharyngeal pouch origin
85. What is the origin of the mandible?
Branchial arch I a)
b) Branchial arch II
c) Branchial arch III
d) Branchial arch IV
e) Not of the branchial arch origin
86. The thyroid gland:
a) Originates from an endodermal outgrowth at the base of the primordial
tongue
b) Is usually detached from the Thyroglossal duct in the adult
Both A and B c)
d) Neither A nor B

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EMBRYOLOGY 1. Which of the following synthesize progesterone? a) Cytotrophoblast b) Syncytiotrophoblast c) Both A and B d) Neither A or B 2. All occur during the morula stage except: a) Attachment to the uterine epithelium takes place b) The location of the cells dictates their fate c) The outer cells pump fluid creating a fluid-filled blastocele d) Tight junctions appear between cells at the periphery, isolating the inner Cells from the uterine fluid 3. During the first week of human development: a) The zona pellicoda is formed b) The cells of the embryo increase in number but become smaller c) The cells of the embryo increase in size d) Implantation is completed e) None of the above 4. During the second week of human development: a) The trophoblast differentiates into cytotrophoblast & syncytiotrophoblast b) The utero-placental circulation begins c) The inner cell mass differentiation into hypoblast and epiblast d) Primary stem villi appear e) All of the above 5. As a result of transverse and longitudinal folding of the embryo: a) The prochordal membrane is moved ventrally and caudally b) Position of yolk sac becomes incorporated into embryonic body c) The primitive groove is moved cranially & dorsally d) Both A and B e) All of the above 6. Which of the following is/are normally always interposed between fetal and maternal blood: a) Extraembronic mesoderm b) Maternal endothelial cells c) Syncytiotrophoblast d) Both A and B e) All of the above 7. Maternal blood normally comes into contact with: a) Syncytiotrophoblast b) Cytotrophoblast c) Fetal blood cells d) Both A and B e) All of the above 8. Which of the following is not a function of the yolk sac in humans? a) Site of origin of primodial germ cells b) Site of origin of fetal blood cells c) Provides nourishment/metabolic reserves for the embryo d) Site of origin of epithelium of the primitive gut e) Facilitates transfer of nutrients into the early embryo 9. At the time of ovulation the endometrium is in the: a) Menstral phase b) Early proliferative phase c) Late proliferative phase d) Early secretory phase e) Late secretory phase 10. Lines in the chorionic after the third developmental week are: a) Cytotrophoblast b) Syncytiotrophopblast c) Both A and B d) Neither A nor B 11. Always normally situated between maternal and fetal blood: a) Cytotrophoblast b) Syncytiotrophoblast c) Both A and B d) Neither A nor B 12. Bleeding may occur near the 13th day of development: a) May be confused with normal menstral bleeding b) Is caused by increased blood flow into lacunar spaces c) Both A and B d) Neither A nor B 13. The extraembryonic membrane which contributes the most tissue to the formation of the placenta is the: a) Amnion b) Chorion c) Yolk sac d) Connecting (body) stalk e) Decidua 14. The extraembryonic epiblast gives rise to or contributes cells to which of the following germ layers? a) Ectoderm b) Mesoderm c) Endoderm d) Both A and B e) All of the above 15. The primitive streak: a) Is derived from the outer cells of the morula b) Is formed during the second week in development c) Persists as the cloacal membrane d) Is the site of involution of epiblast cells to form mesoderm 16. The bilaminar germ disc: a) Consists of hypoblast and epiblast b) Is derived from trophoblast cells c) Both A and B d) Neither A nor B 17. Meiosis is completed within the gonads during gametogenesis in which sex? a) Gametogenesis in human female b) Gametogenesis in human male c) Both A and B d) Neither A nor B 18. Female pronucleus are fully formed: a) Before fertilization b) After fertilization c) Both A and B d) Neither A nor B 19. The conceptus is the: a) Embryo/fetus b) Amnion and Chorion c) Deciduas d) Both A and B e) All of the above 20. Functions of the placenta include all the following except: a) Exchange of maternal and fetal blood b) Exchange of nutrients and electrolytes c) Hormone production d) Gas exchange e) Transmission of maternal antibodies 21. The secondary oocyte undergoes completion of the second maturation division: a) Before ovulation b) At fertilization c) After ovulation d) Prenatally e) At puberty 22. The ovarian follicular cells release: a) Follicle stimulating hormone b) Chorionic Gonadotrophin c) Estrogen d) Both A and B e) All of the above 23. The most common site for implantation in ectopic pregnancy is the:: a) Internal os of the uterus b) Mesentary c) Ovary d) Oviduct e) None of the above 24. At the time of initiation of implantation: a) The endometrium is in the proliferative phase b) The predominant ovarian hormone is progesterone c) The conceptus is approximately one day "old" (postfertilization) d) Both A and B e) All of the above 25. All is true about primary oocytes except: a) Are arrested in prophase of the first meiotic division b) Continue to form after birth c) Together, with surrounding epithelial cells, for a primordial follicle d) Suffer from atretion until only approximately 40, 000 are left at puberty 26. Trophoblast and inner cell mass portions are evident in the: a) Conceptus before implantation has started b) Conceptus after implantation has started c) Both A and B d) Neither A nor B 27. At fertilization: a) The ovum completes the 2nd meiotic division b) Cleavage is initiated c) The sex of the individual is determined d) The diploid number of chromosomes is restored e) All of the above 28. All the following are derivatives of mesoderm except: a) Dermatomes b) Myotomes c) Sclerotomes d) Endothelium e) Yolk sac 29. The prechordal plate: a) Is a patent inducer region for future head structures b) Becomes a portion of the oropharyngeal membrane c) Is formed within the embryonic epiblast d) Both A and B e) All of the above 30. At the time of fertilization, the endometrium is in the: a) Proliferative phase b) Secretory phase c) Menstral phase d) Both B and C 31. Which of the following contains abundant nutrient reserves? a) Female gametes b) Male gametes c) Both A and B d) Neither A nor B 32. Which of the following determines the genetic sex of the zygote? a) Female gametes b) Male gametes c) Both A and B d) Neither A nor B 33. Which of the following is found in the early placenta? a) Cytotrophoblast b) Syncytiotrophoblast c) Both A and B d) Neither A nor B 34. The space between the somatopleuric and splanchnopleuric extraembryonic mesoderm is known as: a) The primitive yolk sac b) The secondary yolk sac c) The blastocele d) The amniotic cavity e) The extraembryonic coelom 35. As a result of fertilization: a) Sex of the offspring is determined b) The diploid number of chromosomes is restored c) Cleavage divisions are initiated d) Genetic heterogeneity is maintained e) All of the above 36. At the time of the first missing menstrual period, the conceptus is: a) 3 days old b) 5 days old c) 3 weeks old d) 5 weeks old 37. Primary oocytes have developed by the time of birth. From puberty to menopause, these germ cells remain suspended in the meiotic prophase. The oocyte of a mature follicle is induced to undergo the first meiotic division just prior to ovulation as a result of which of the following hormonal stimuli: a) The cessation of progesterone secretion b) The gradual elevation of FSH titers c) The low estrogen titers associated with the maturing follicle d) The slow elevation of progesterone produced by luteal cells e) The surge of luteinizing hormone initiated by high estrogen titers 38. By the 4th day of development, fluid accumulation by the morula results is separation of the cells into trophoblasts and embryoblasts, or inner cell mass. From the 8th-12th day of development, the role of trophoblasts includes all of the following except: a) Enclosure of inner cell mass and blastocyst cavity b) Formation of embryo proper c) Invasion of endometrial epithelium d) Production of hormones e) Production of 2 distinct cell populations by differentiation 39. A 26 year old man had viral influenza with fever 39.5o for 3 days. Since spermatogenesis cannot occur above a scrotal temperature of 35.5 o, he was left with no viable sperm on his recovery. The time required for spermatogenesis, spermiogenesis, passage of a viable sperm to the epididymis is approximately: a) 3 days b) 1 week c) 5 weeks d) 2 months e) 4 months 40. A 25 year old female states that she has a very regular menstrual cycle that is 24 days in length. The projected time of ovulation for this woman would be about the: a) 14th day following start of her last menstrual period b) 12th day following end of her last menstrual period c) 12th day following end of her last menstrual period d) 10th day following end of her last menstrual period e) 10th day following beginning of her last menstrual period 41. The chorionic villi of the placenta are most numerous in the region of the: a) Decidua capsularis b) Chorionic plate c) Basal plate d) Maternal septae e) Decidua basalis 42. The following list contains components of the "placental barrier" during the first trimester of pregnancy. Which one component is disappearing during late pregnancy? a) The endothelial lining of fetal capillaries b) The cytotrophoblast c) The syncytiotrophoblast d) The basement membrane of fetal capillaries e) None of the above 43. All of the following placental transport mechanism require the expenditure of cellular energy except: a) Active transport b) Pinocytosis c) Simple diffusion d) Facilitated diffusion 44. A full-term male infant has vomited 1 hour after suckling. There has been failure to gait during the first 2 weeks postnatal. The vomitus is not bile-stained and no respiratory dilation is evident. Wxamination reveals an abdomen neither tense nor bloated. The most probable explaination is: a) Congenital hypertrophic pyloric stenosis b) Duodenal atresia c) Patient ileal diverticulum d) Imperforate anus e) Tracheo-esophageal fistula 45. A fistula is found that runs between the palatine tonsil fossa and the skin of the neck immediately anterior to the sternocleidomastoid muscle. Developmetal failure occured: a) With a rupture of the tissue between the third branchial cleft and third pharyngeal pouch b) With a failure to close the first branchial cleft c) With a failure to obliterate the cervical sinus d) Both A and B e) All of the above 46. Which statement about fetal blood vessels is false: a) The ductus arteriosus carries blood from the aorta to the pulmonary trunk b) The foramen ovale carries blood from the right atrium to the left atrium c) The umbilical vein carries blood from the umbilical cord via the ductus venosus to the inferior vena cave d) Implantation is completed e) None of the above 47. Regarding the blastocyst all the following are true except: a) Has more cells than a morula b) Has inner cell mass c) Has syncytotrophoblast d) Has trophoblast cells e) May have zona pellucida 48. Derivatives of the mesodermal cell layer of the embryo include all the following except: a) Adrenal cortex b) Gonads c) Peritoneal serosa d) Spleen e) Liver parenchyma 49. In the developing embryo, the first bone to begin ossification is the: a) First rib b) Humerus c) Tibia d) Scapula e) Clavicle 50. Fallot's tetralogy includes all the following except: a) Pulmonary stenosis b) Aortic overriding c) Ventricular septal defect d) Patency of ductus arteriosus e) Hypertrophy of the right ventricle 51. The trachea develops from the: a) Septum transversum b) Fifth branchial arch c) Thyroglossal canal d) Pulmonary mesenchyme e) Foregut 52. In the developing pancreas, the dorsal bud contributes all the following except: a) Body of the pancreas b) Distal portion of the main pancreatic duct c) Secondary pancreatic duct d) Uncinate process e) Upper half of the head of the pancreas 53. All of the following structures contribute in development of diaphragm except: a) Body wall b) Primitive mesoesophagus c) Septum transversum d) Pleuro-pericardial membrane e) Pleuro-peritoneal membrane 54. Spina bifida is a failure of fusion between the: a) Left and right halves of the vertebral column b) Pedicle and centrum of the vertebra c) Left and right laminae of the vertebra d) Both A and B e) All of the above 55. A urachal fistula represents a remnant of the: a) Cloaca b) Allantois c) Urogenital sinus d) Hindgut e) Mesonephric duct 56. What is the origin of the mucosa of the middle ear? a) Neural ectoderm b) Surface ectoderm c) Mesoderm d) Endoderm e) None of the above 57. The left sixth aortic arch gives rise to the: a) Hemiazygos vein b) Coronary sinus c) Ligamentum arteriosum d) Ligamentum venosum e) No remnants are found in this structure in the adult 58. The posterior pituitary is of which origin: a) Endoderm b) Mesoderm c) Ectoderm d) Endoderm and mesoderm e) Endoderm and ectoderm 59. The parathyroid glands: a) They are 3 in number b) They secrete Calcitonia c) They develop from the 2nd pharyngeal arch d) They normally lie anterior to the thyroid gland e) They develop from the 3rd and 4th pharyngeal arches (pouches) 60. Unilateral upper lip cleft is due to failure of fusion of: a) Medial nasal processes b) Maxillary and lateral nasal processes c) Maxillary and medial nasal processes on one side d) Maxillary and mandibular processes e) Medial and lateral nasal processes unilaterally 61. In which of the following is precursor cell mitosis evident after puberty: a) Female gametes b) Male gametes c) Both A and B d) Neither A nor B 62. What is the origin of the mucosa of the oral pharynx? a) Branchial arch I b) Branchial arch II c) Branchial arch III d) Branchial arch IV e) Not of branchial arch origin 63. Which of the following is formed from portions of one sclerotome: a) Vertebral centrum b) Intervertebral disc (annulus fibrosus) c) Both A and B d) Neither A nor B 64. The clavicle is: a) The first bone to begin ossification b) The first bone to complete ossification c) Intramembranous in origin d) Both A and C e) All of the above 65. Limb musculature: a) Relies on spinal nerve to aid the differentiation process b) Begins as mesenchymal condensation c) Is derived from somatic mesoderm d) Splits into flexor and extensor compartments e) All of the above 66. Cervical sinus develop from: a) Pharyngeal pouch 1 b) Pharyngeal pouch 2 c) Pharyngeal pouch 3 d) Pharyngeal pouch 4 e) This structure is not derived from pharyngeal pouch 67. Parafollicular cells of the thyroid gland develop from: a) Pharyngeal pouch 1 b) Pharyngeal pouch 2 c) Pharyngeal pouch 3 d) Pharyngeal pouch 4 e) This structure is not derived from pharyngeal pouch 68. During the third to sixth months of pregnancy, the structure primarily responsible for erythropoiesis is the: a) Bone marrow b) Liver c) Spleen d) Thymus e) Yolk sac 69. Structures derived from the hind gut in the male include all the following except the: a) Allantois b) Descending colon c) Inferior portion of the anal canal d) Prostatic urethtra e) Urinary bladder 70. With regard to the formation of the placenta all of the following are false except: a) Tertiary chorionic villi differ from primary chorionic villi by the presence of blood vessels b) Primary chorionic villi contain only syncytiotrophoblast c) The intervillous space contains fetal blood d) The deciduas basalis and the chorion leave constitute the placenta e) The umbilical cord contains a loose connective tissue called Wharton's jelly 71. The endocardial cushions are involved in the formation of all of the following except: a) Right and left atrioventricular canals b) Pectinate muscles c) Atrioventricular valves d) Membranous part of the interventricular septum 72. Which of the following is the most common type of congenital heart malformation? a) Dextrocardia b) Atrial septal defect c) Ectopic cordis d) Ventricular septal defect e) Transposition of the great vessels 73. The adult left atrium is derived embryologically primarily from the: a) Right horn of the sinus venosus b) Primitive pulmonary vein c) Sinus venarum d) Bulbus cordis e) Ledt horn of the sinus venosus 74. The primitive aortic arch pattern is transformed into an adult arterial arrangement. Which pair of arteries (embryonic/adult) is incorrect: a) 6th arch/ pulmonary artery b) Right 4th arch/ right subclavian c) Left 4th arch/ left subclavian d) 2nd arch/ stapedial artery e) 3rd arch/ common and internal carotid 75. Azygos vein is derived from the: a) Right vitelline vein b) Right subcardinal vein c) Right anterior cardinal d) Right supracardinal vein e) All of the above 76. All of the following are true concerning development of the bronchi except: a) Lung buds first form at the caudal end of the laryngotracheal tube b) During the 5th week of development, the lung bud grows laterally into the primitive pleural cavities (pericardioperitoneal canals) c) Third generation bronchi supply bronchopulmonary segments d) The pulmonary cartilage, smooth muscle, and connective tissue are derived from the lung bud endoderm e) By 24 weeks of development, respiratory bronchioles are present 77. Tracheoesophageal fistula with blind ending esophagus results in: a) Polyhydraminos (more than usual amount of amniontic fluid) b) Oligohydraminos (less than usual amount of amniotic fluid) c) Both A and B d) Neither A nor B 78. The definitive diaphragm is formed by fusions of all except one of the following: a) Mesoesophagus b) Septum transversum c) Pleuroperitoneal membranes d) Mesentery of duct of Cavier e) Mesoderm of the body wall 79. Paraxial (somite) mesoderm gives rise to: a) Muscles of mastication b) Muscles in the stomach c) Both A and B d) Neither A nor B 80. The embryonic epiblast gives rise to or contributes cells to which of the following germ layers? a) Ectoderm b) Mesoderm c) Endoderm d) Both A and B e) All of the above 81. Gonia cells produced during gametogenesis are usually present in 65-year old individuals of which sex: a) Gametogenesis in human female b) Gametogenesis in human male c) Both A and B d) Neither A nor B 82. All of the following are true of amniotic fluid except: a) It is derived from maternal blood b) It is swallowed by the fetus from the beginning of the 5th month c) It restricts fetal movement within the amniotic cavity d) It absorbs jolts to the fetus 83. Epithelium of the tongue posterior to the sulcus terminals is derived from the: a) First branchial arch b) Second branchial arch c) Third branchial arch d) Fourth branchial arch e) Not of branchial arch origin 84. What is the origin of the superior parathyroid glands? a) Pharyngeal pouch I b) Pharyngeal pouch II c) Pharyngeal pouch III d) Pharyngeal pouch IV e) Not of pharyngeal pouch origin 85. What is the origin of the mandible? a) Branchial arch I b) Branchial arch II c) Branchial arch III d) Branchial arch IV e) Not of the branchial arch origin 86. The thyroid gland: a) Originates from an endodermal outgrowth at the base of the primordial tongue b) Is usually detached from the Thyroglossal duct in the adult c) Both A and B d) Neither A nor B Name: Description: ...
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