Embryology Test 1

Question 1

During spermatozoa maturation protamines replace histones to facilitate chromatin condensation. When or where are sperm DNA protamines removed and replaced by histones?

Answer 1

In the oocyte after fertilization

Question 2

When does the zona pellucida “hatching” occur?

Answer 2

Blastocyst stage

Question 3

The amniotic cavity is formed when?

Answer 3

A cavity forms in the epiblast

Question 4

The chorionic cavity or extraembryonic coelom forms between which two layers?

Answer 4

Splanchnic extraembryonic mesoderm and somatic extraembryonic mesoderm.

Question 5

Where does the intraembryonic coelom form during the week 3 of embryonic development?

Answer 5

Lateral plate mesoderm

Question 6

When does tetras formation and crossing over occur?

Answer 6

Prophase 1 of meiosis 1

Question 7

How many chromosomes and how many copies of the DNA (n) would be present in a human primary oocyte?

Answer 7

46 and 4N

Question 8

How many chromosomes and how many copies of DNA (n) would be present in a human secondary oocyte?

Answer 8

23 and 2N

Question 9

How long does the embryonic period last?

Answer 9

8 weeks

Question 10

Which sequence best reflects the sperm pathway through the male reproductive system?

Answer 10

Seminiferous tubules, rete testis, efferent ductules, epididymis, ductus deferens, ejaculatory duct, prostatic urethra, membranous urethra, penile urethra

Question 11

Approximately 60% of seminal fluid derives from a yellowish, alkaline, viscous fluid produced by which source?

Answer 11

Seminal vesicles

Question 12

Which structure would not be included in or related to the female vestibule?

Answer 12

Mons pubis

Question 13

When during the cell cycle does centriole replication occur?

Answer 13

S phase

Question 14

Sister chromatid separation due to kinetochore microtubule shortening occurs during which phase of mitosis?

Answer 14

Anaphase

Question 15

Meiosis occurs during which phase of spermatogenesis?

Answer 15

Spermatocyte phase

Question 16

During spermiogenesis the spermatid actually reorients so the flagellum will extend into the seminiferous tubule lumen. What event initiates this reorientation?

Answer 16

Acrosomal sac formation

Question 17

The lining of the body of the uterus is referred to as the?

Answer 17

Endometrium

Question 18

Which area of the female reproductive tract is characterized by by large glands that shift their secretion around the time of ovulation?

Answer 18

Endocervical canal

Question 19

Which area of the female reproductive tract has a lining epithelium described as a nonkeratinized stratified squamous epithelium and there are no glands?

Answer 19

Vagina

Question 20

How would you classify an ovarian follicle made up of multiple layers of Granulosa cells with several small fluid filled spaces?

Answer 20

Secondary follicle

Question 21

When does zona pellucida formation begin?

Answer 21

Early primary follicle

Question 22

Identify this collection of cells. (Large oocyte surrounded by one layer of follicle cells, with a small zona pellucida in between, and surrounded by stroma cells

Answer 22

Early primary follicle

Question 23

Which cells or structures would not be present in a mature Graafian immediately prior to ovulation?

Answer 23

Primary oocyte

Question 24

Circulating levels of which hormone produced by the ovary will reach their peak level during the follicular stage?

Answer 24

Estrogen

Question 25

The circulating levels of which hormone produced by the anterior pituitary will be highest immediately prior to ovulation?

Answer 25

Lutenizing hormone (LH)

Question 26

The circulating levels of which hormone produced by the ovary will reach their peak levels during the lute all phase?

Answer 26

Progesterone

Question 27

Which hormone is essential to final thickening of the functional endometrium during the secretory phase?

Answer 27

Progesterone

Question 28

Where does capacitation occur?

Answer 28

Oviduct isthmus

Question 29

Which major organelle is contributed to the zygote by the sperm during cell fertilization?

Answer 29

Centrioles

Question 30

Sperm cell binding to the oocyte membrane initiates the "cortical reaction". What does that mean?

Answer 30

Cortical granule enzyme release "hardens" the zona pellucida

Question 31

What is amphimixis?

Answer 31

Male/female nuclear fusion

Question 32

Correct sequence of structures would be:

Answer 32

Zygote, morula, blastocysts, gastrula, neurula

Question 33

Why is compaction important?

Answer 33

Cells segregate into inner cell mass (embryoblast) and outer cell mass (trophoblast)

Question 34

Why is the zona pellucida important?

Answer 34

Prevents polyspermia, prevents premature implantation, and prevents maternal immune system from attacking the conceptus

Question 35

Which two ovarian cells are responsible for estrogen/progesterone production?

Answer 35

Theca cell and Granulosa cells

Question 36

Following compaction, the morula constists of 2 cell populations; the inner cell mass and the outer cell mass. What is the fate of the outer cell mass?

Answer 36

it forms the trophoblast

Question 37

Once implantation begins, the syncytiotrophoblast rapidly becomes the source of which critical hormone?

Answer 37

human chorionic gonadotropin

Question 38

Which structure is not present on day 7 post fertilization?

Answer 38

Heuser's (exocoelomic) membrane

Question 39

What is the decidual reaction?

Answer 39

endometrial cells accumulate glycogen and lipids

Question 40

The primitive streak marks the beginning of gastrulation. What will be the fate of the first cells to pass through the primitive streak?

Answer 40

will become intraembryonic endoderm

Question 41

The neurenteric canal provides a transient passageway btw which 2 area?

Answer 41

amnion and yolk sac

Question 42

The notochord develops from which cell population?

Answer 42

axial mesoderm

Question 43

Blood Island and thus bloood cell formation begin where?

Answer 43

extraembryonic splanchnic mesoderm

Question 44

Following primitive streak and embyonic endoderm formation, the initial mesoderm cells that migrate anteriorly along the midline become which population of cells?

Answer 44

prechordal plate

Question 45

The first somites develop from which somitomeres?

Answer 45

#8

Question 46

The somites develop from which area or layer?

Answer 46

paraxial mesoderm

Question 47

Based on amnion/chorion arrangement, which situation would most likely produce conjoined twins?

Answer 47

monochorionic, monoamnionic twins

Question 48

Splitting of the embryo at the inner cell mass stage would result is which membrane arrangment?

Answer 48

monochorionic, diamnionic twins

Question 49

Which extraembyonic membrane actually cober the umbilical cord?

Answer 49

amnion

Question 50

The placental barrier "thins" during gestation to improve exchange. How does this occur?

Answer 50

Loss of mesenchyme and cytotrophoblast within the placental villi

Question 51

The somatopleure is a membrane comprised of which two tissues?

Answer 51

ectoderm and somatic mesoderm

Question 52

What is the primary source of amnionic fluid after 12 weeks of gestation?

Answer 52

fetal urine production

Question 53

Why is the allantois important?

Answer 53

umbililcal cord blood vessel formation

Question 54

Which layer disappears during gestation?

Answer 54

decidua capsularis

Question 55

A woman has a difficult time delivering an infant because of a large bulging mass in the posterior area of the infants buttocks. After delivery, gentle rectal palpation indicated that this tissue extended up into the pelvis. Biopsy of the tissue revealed the presence of shin, cartilage, bone, nervous tissue, cardiac and skeletal muscle, and intestinal epithelium. What is the diagnosis?

Answer 55

sacrococcygeal teratoma

Question 56

List 3 ectoderm derived cell populations that result from neurulation.

Answer 56

neuroepithelial cells, neural crest cells, surface ectoderm

Question 57

List 3 components that make up the chorion.

Answer 57

syncytiotrophoblast, cytotrophoblast, and extraembryonic somatic mesoderm

Question 58

List 3 layers that make up the late gestation placental membrane.

Answer 58

syncytiotrophoblast, fused basal lamina, and fetal endothelium

Question 59

Explain why meiosis is important.

Answer 59

it reduces the number of chromosomes, enables genetic variability in conceptus through synapsis and crossing over, exchange of genes through independent assortment and crossing over

Question 60

Describe the structure of a mature Graafian follicle

Answer 60

has a secondary oocyte, zona pellucida, corona radiata, cumulus cells, cumulus oophorus, large fluid-filled antrum, granulosa cells, theca externa and theca interna

Question 61

What is the site of action (specific cells) for FSH and LH in males and females.

Answer 61

FSH: males - sertoli cells. females - granulosa cells LH: males - Leydig cells, females - theca cells

Question 62

Outline the major epiblast derivatives during human gastrulation (primitive streak).

Answer 62

Endoderm: primitive gut Messoderm: axial - prechordal plate and notochord; paraxial - somites; intermediate - genitourinary system; lateral - somatic (somatopleure) and splanchnic (splanchnopleure) Ectoderm: skin ectoderm, neural plate/fold ectroderm - neural tube neuroepithelial and neural crest cells