Question 1

Although the early digestive system maintains contact with the embryonic yolk sac,it does not gain any nourishment from the sac.Instead,the yolk sac is involved with the formation of

Accepted Answer

A)  the heart and lungs.
B)  the reproductive organs.
C)  blood vessels and blood cells.
D)  bones.
E)  skeletal muscle tissue.F) A) and B)
G) B) and E)

Question 2

The axial skeleton,most muscle,cartilage,dermis,and connective tissues are derived from blocklike embryonic structures called

Accepted Answer

A)  teratogens.
B)  dermatomes.
C)  notochords.
D)  lateral plates.
E)  somites.F) C) and E)
G) B) and E)

Question 3

Neural crest cells give rise to

Accepted Answer

A)  melanocytes.
B)  the adrenal medulla.
C)  spinal ganglia
D)  skeletal and muscular components of the head.
E)  All of the choices are correct.F) A) and D)
G) B) and C)

Question 4

The function of the chorion (one of the extraembryonic membranes) is to

Accepted Answer

A)  prevent desiccation of the embryo.
B)  assist in the formation of the circulatory system.
C)  form red blood cells.
D)  aid in the formation of the placenta.
E)  cover the embryo in a protective layer of mucus.F) D) and E)
G) A) and B)

Question 5

The blastodisc (bilaminar germinal disc) of the early embryo consists of the

Accepted Answer

A)  hypoblast and the epiblast.
B)  hypoblast and the trophoblast.
C)  epiblast and the trophoblast.
D)  hypoblast and the cytotrophoblast.
E)  cytotrophoblast and the epiblast.F) B) and D)
G) A) and D)

Question 6

From which primary germ layer is the dermis of the skin derived?

Accepted Answer

A)  Ectoderm
B)  Mesoderm
C)  EndodermD) A) and B)
E) A) and C)

Question 7

What would be the result if the notochord failed to develop?

Accepted Answer

A)  The digestive system could not develop properly.
B)  The circulatory system could not develop properly.
C)  The skeletal system could not develop properly.
D)  The nervous system could not develop properly.
E)  The reproductive system could not develop properly.F) B) and C)
G) A) and E)

Question 8

The event called "crossing over" in meiosis results in

Accepted Answer

A)  greater genetic variety in sex cells and thus in embryos.
B)  less genetic variety in sex cells.
C)  greater vitality of sex cells making them more active.
D)  a change in the gender (sex) of the embryo.
E)  irreversible mutations.F) C) and D)
G) None of the above

Question 9

Some estimates claim that approximately ______ percent of all pregnancies result in spontaneous abortion,many due to chromosomal abnormalities.

Accepted Answer

A)  10
B)  20
C)  30
D)  40
E)  50F) A) and B)
G) B) and D)

Question 10

At its formation,a morula consists of ______ cells.

Accepted Answer

A)  4
B)  8
C)  16
D)  32
E)  64F) All of the above
G) A) and B)

Question 11

-This figure depicts cleavage.Number 1 indicates a pre-embryo in the _________ stage of development.

Accepted Answer

A)  2-cell
B)  4-cell
C)  8-cell
D)  morula
E)  blastocystF) A) and E)
G) A) and D)

Question 12

Which is not correct concerning cephalocaudal folding of the embryonic disc?

Accepted Answer

A)  It occurs before the primary germ layers have formed.
B)  It occurs in the cephalic and caudal regions of the embryo.
C)  It occurs because of differential growth in different regions of the embryonic disc.
D)  It occurs during the late third and fourth weeks of development.
E)  It helps create the future head and buttocks regions of the embryo.F) B) and E)
G) A) and C)

Question 13

The secondary oocyte enters into an arrested state during its development.In what stage of development does this occur?

Accepted Answer

A)  During metaphase I
B)  During telophase I
C)  During prophase II
D)  During metaphase II
E)  During telophase IIF) B) and C)
G) A) and D)

Question 14

What would happen if more than one sperm penetrated a secondary oocyte,an event termed polyspermy?

Accepted Answer

A)  Identical twins would result.
B)  The sperm with the most advanced chromosomes would merge with the female nucleus.
C)  The extra sperm would most likely fertilize one of the polar bodies.
D)  The resulting zygote would not develop.
E)  This never happens due to genetic controls.F) A) and D)
G) A) and E)

Question 15

During this fetal stage,lanugo covers the skin and the limbs near their final proportions.

Accepted Answer

A)  Weeks 1-8
B)  Weeks 9-12
C)  Weeks 13-16
D)  Weeks 17-20
E)  Weeks 21-38F) B) and E)
G) C) and D)

Question 16

The amnion is one of the extraembryonic membranes,and its function is to

Accepted Answer

A)  prevent desiccation of the embryo.
B)  allow fluid to enter the placenta.
C)  form the plasma portion of the blood.
D)  give the embryo nourishment.
E)  permit implantation to occur.F) A) and C)
G) A) and E)

Question 17

During embryonic development,a process called transverse folding creates the

Accepted Answer

A)  digestive and respiratory tracts.
B)  pelvic girdle and lower appendages.
C)  cylindrical trunk or torso region of the embryo.
D)  primary germ layers.
E)  neural tube.F) B) and D)
G) A) and C)

Question 18

The single cell resulting from fertilization is a/an

Accepted Answer

A)  blastocyst.
B)  morula.
C)  trophoblast.
D)  embryoblast.
E)  zygote.F) All of the above
G) C) and D)

Question 19

This figure shows a superior view of the developing embryo.What structure does number 1 indicate?

Accepted Answer

A)  Yolk sac
B)  Notochord
C)  Primitive streak
D)  Epiblast
E)  HypoblastF) All of the above
G) A) and B)

Question 20

Following ovulation,how long does a secondary oocyte remain viable?

Accepted Answer

A)  For about 1-2 hours
B)  Approximately 12 hours
C)  For about 1 day
D)  Between 3-5 days
E)  For approximately 1 weekF) B) and C)
G) B) and D)

Exam 3: Embryology

At its formation,a morula consists of ______ cells.

Correct AnswerverifiedShow Answer

This figure shows a superior view of the developing embryo.What structure does number 1 indicate?

Correct AnswerverifiedShow Answer

Neural crest cells give rise to

Correct AnswerverifiedShow Answer

The secondary oocyte enters into an arrested state during its development.In what stage of development does this occur?

Correct AnswerverifiedShow Answer

Although the early digestive system maintains contact with the embryonic yolk sac,it does not gain any nourishment from the sac.Instead,the yolk sac is involved with the formation of

Correct AnswerverifiedShow Answer

Some estimates claim that approximately ______ percent of all pregnancies result in spontaneous abortion,many due to chromosomal abnormalities.

Correct AnswerverifiedShow Answer

The function of the chorion (one of the extraembryonic membranes) is to

Correct AnswerverifiedShow Answer

From which primary germ layer is the dermis of the skin derived?

Correct AnswerverifiedShow Answer

-This figure depicts cleavage.Number 1 indicates a pre-embryo in the _________ stage of development.

Correct AnswerverifiedShow Answer

What would happen if more than one sperm penetrated a secondary oocyte,an event termed polyspermy?

Correct AnswerverifiedShow Answer

During this fetal stage,lanugo covers the skin and the limbs near their final proportions.

Correct AnswerverifiedShow Answer

Which is not correct concerning cephalocaudal folding of the embryonic disc?

Correct AnswerverifiedShow Answer

What would be the result if the notochord failed to develop?

Correct AnswerverifiedShow Answer

The blastodisc (bilaminar germinal disc) of the early embryo consists of the

Correct AnswerverifiedShow Answer

The event called "crossing over" in meiosis results in

Correct AnswerverifiedShow Answer

The single cell resulting from fertilization is a/an

Correct AnswerverifiedShow Answer

The axial skeleton,most muscle,cartilage,dermis,and connective tissues are derived from blocklike embryonic structures called

Correct AnswerverifiedShow Answer

The amnion is one of the extraembryonic membranes,and its function is to

Correct AnswerverifiedShow Answer

Following ovulation,how long does a secondary oocyte remain viable?

Correct AnswerverifiedShow Answer

During embryonic development,a process called transverse folding creates the

Correct AnswerverifiedShow Answer

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