Exam 1 Practice Quiz

Question 1

Mesoderm is formed from:
A. hypoblast
B. amnioblasts
C. extraembryonic ectoderm
D. epiblast
E. notochordal cells

Answer 1

D. epiblast

Question 2

All of the following structures are necessary for blastocyst implantation EXCEPT:
A. embryoblast in progestational phase
B. cytotrophoblast
C. zona pellucida
D. synciotrophoblast
E. functional layer of endometrium

Answer 2

C. zona pellucida

Question 3

Between which two layers is extraembryonic mesoderm located?
A. exocoelomic membrane and cytotrophoblast
B. exocoelomic membrane and synciotrophoblast
C. epiblast and hypoblast
D. synciotrophoblast and cytotrophoblast
E. synciotrophoblast and endometrium

Answer 3

A. exocoelomic membrane and cytotrophoblast

Question 4

Which of the following statements regarding the epiblast is CORRECT?
A. it is composed of small cuboidal cells
B. it forms the primitive streak
C. it forms the roof of the blastocyst cavity
D. notochordal cells intercalate into it

Answer 4

B. it forms the primitive streak

Question 5

The process of gastrulation is first indicated by the formation of the
A. prechordal plate
B. somites
C. neural tube
D. primitive streak
E. cloacal membrane

Answer 5

D. primitive streak

Question 6

Why are you not surprised? A newborn infant presents with craniofacial abnormalities and a cardiac defect involving the outflow tract of the heart.
A. the mother took fertility drugs
B. body folding is important for both areas and may produce combined effects
C. neural crest cells contribute greatly to the development of both regions
D. paraxial mesoderm contributes to the formation of both areas

Answer 6

C. neural crest cells contribute greatly to the development of both regions

Question 7

Which of the following is not derived from ECTODERM?
A. forebrain
B. epidermis
C. enamel of the tooth
D. mammary gland
E. dermis of the skin

Answer 7

E. dermis of the skin

Question 8

If an embryo failed to form the mesoderm germ layer, which of the following would not develop?
A. intestinal epithelia
B. hindbrain
C. aorta
D. Schwann cells
E. nails

Answer 8

C. aorta

Question 9

Where are melanocytes derived from?
A. neural crest
B. mesenchyme
C. endoderm
D. dermis
E. mesoderm

Answer 9

A. neural crest

Question 10

The amnionic cavity appears on the 8th day as a slit like space between the trophoblast and the
A. chorion
B. embryoblast
C. extraembryonic mesoderm
D. exocoelomic membrane
E. connecting stalk

Answer 10

B. embryoblast

Question 11

All of the following structures are necessary for blastocyst implantation EXCEPT?
A. trophoblast layer
B. functional layer of endometrium
C. zona pellucida

Answer 11

C. zona pellucida

Question 12

Which of the following layers of the embryo is recognizable at the end of the first week?
A. ectoderm
B. hypoblast
C. mesoderm
D. epiblast

Answer 12

B. hypoblast

Question 13

Of the 200-600 million sperm that are contained in a normal ejaculate, approximately how many will reach the site of fertilization?
A. 50-100 thousand
B. 200-500
C. 10-20 million
D. 50-100 million
E. 5-15 thousand

Answer 13

B. 200-500

Question 14

After the first cleavage division, the 8 to 32 cell stage is referred to as the:
A. morula
B. blastocyst
C. gastrula
D. zygote

Answer 14

A. morula

Question 15

The secondary oocyte completes the second meiotic division
A. before ovulation
B. at fertilization
C. during ovulation
D. before birth

Answer 15

B. at fertilization

Question 16

The notochordal process lengthens by migration of cells from the
A. prochordal plate
B. primitive streak
C. neural plate
D. primitive node

Answer 16

D. primitive node

Question 17

All of the following regarding the 3rd week of development are correct EXCEPT one. Which one is the EXCEPTION?
A. lower limb buds are visible
B. somites begin to form
C. the notochord induces the formation of the neural tube
D. heart tubes begin to fuse

Answer 17

A. lower limb buds are visible

Question 18

All of the following statements regarding the THIRD week of development are correct EXCEPT one. Which one is the EXCEPTION?
A. neural plate formation begins
B. pharyngeal arches begin to form
C. the primitive knot is rostral to the primitive streak
D. all 3 definitive germ layers appear
E. the prechordal plate is still present

Answer 18

B. B. pharyngeal arches begin to form

Question 19

The appearance of what structure is the hallmark for the beginning of gastrulation?
A. formation of the amnion
B. formation of the secondary yolk sac
C. elaboration of the extraembryonic mesoderm
D. formation of the primitive streak

Answer 19

D. formation of the primitive streak

Question 20

Fertilization accomplishes all of the following EXCEPT one. Which one is the EXCEPTION?
A. results in species variation
B. restores the normal diploid number
C. determines the sex of the new individual
D. stimulates the secondary oocyte to complete the first meiotic division
E. initiates cleavage

Answer 20

D. stimulates the secondary oocyte to complete the first meiotic division

Question 21

The definitive fate of the primitive pit is which of the following?
A. it becomes the notochord
B. it becomes the septum transversum
C. it differentiates into the neural plate
D. no answer text provided
E. nothing

Answer 21

E. nothing